chore(release): 0.0.11

- Bump `@opencode-ai/plugin` dependency from 1.2.27 to 1.3.0.
- Introduce `cleanup` command in CLI with force and remote options.
- Export `cleanupMultiModel` from core index.
- Register `multi-model-cleanup` tool in plugin and update exports.
- Add `CleanupOptions` and `CleanupResult` types to define cleanup behavior and results.

.githooks/post-checkout

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# Post-checkout hook to run bun install when switching branches or checking out files
+# This ensures dependencies are always up to date
+
+# Only run if package.json or bun.lock exist (indicating a Node/Bun project)
+if [ -f "package.json" ] || [ -f "bun.lock" ]; then
+  echo "Running bun install..."
+  bun install
+fi

.opencode/package-lock.json

@@ -1,52 +0,0 @@
-{
-  "name": "opencode-multi-model-tools",
-  "lockfileVersion": 3,
-  "requires": true,
-  "packages": {
-    "": {
-      "name": "opencode-multi-model-tools",
-      "dependencies": {
-        "@opencode-ai/plugin": "1.2.24"
-      },
-      "devDependencies": {
-        "@types/node": "^25.5.0"
-      }
-    },
-    "node_modules/@opencode-ai/plugin": {
-      "version": "1.2.24",
-      "license": "MIT",
-      "dependencies": {
-        "@opencode-ai/sdk": "1.2.24",
-        "zod": "4.1.8"
-      }
-    },
-    "node_modules/@opencode-ai/sdk": {
-      "version": "1.2.24",
-      "license": "MIT"
-    },
-    "node_modules/@types/node": {
-      "version": "25.5.0",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-25.5.0.tgz",
-      "integrity": "sha512-jp2P3tQMSxWugkCUKLRPVUpGaL5MVFwF8RDuSRztfwgN1wmqJeMSbKlnEtQqU8UrhTmzEmZdu2I6v2dpp7XIxw==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "undici-types": "~7.18.0"
-      }
-    },
-    "node_modules/undici-types": {
-      "version": "7.18.2",
-      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-7.18.2.tgz",
-      "integrity": "sha512-AsuCzffGHJybSaRrmr5eHr81mwJU3kjw6M+uprWvCXiNeN9SOGwQ3Jn8jb8m3Z6izVgknn1R0FTCEAP2QrLY/w==",
-      "dev": true,
-      "license": "MIT"
-    },
-    "node_modules/zod": {
-      "version": "4.1.8",
-      "license": "MIT",
-      "funding": {
-        "url": "https://github.com/sponsors/colinhacks"
-      }
-    }
-  }
-}

.opencode/package.json

@@ -6,7 +6,7 @@
     "test": "bun test"
   },
   "dependencies": {
-    "@opencode-ai/plugin": "1.2.27"
+    "@opencode-ai/plugin": "1.3.0"
   },
   "devDependencies": {
     "@types/bun": "^1.3.10",

.opencode/plans/archive/1774116737450-clever-canyon.md

@@ -0,0 +1,475 @@
+---
+model: opencode-go/glm-5
+---
+
+# Plan: Add `opencode-multi-model cleanup` Command
+
+## Overview
+
+Add a new`cleanup` command that deletes all archive tags (format: `archive/*`) from localand remote git repositories. Archive tags are created by the `close` command to preserve branch state before deletion.
+
+## User Requirements
+
+1. **Scope**: Only archive tags (not orphaned worktrees/branches)
+2. **Confirmation**: Prompt by default, `--force` to skip
+3. **Remote handling**: Delete from both local and remote by default
+4. **Preview**: Show count of tags, not full list
+5. **Remote discovery**: Check `git remote -v` for available remotes
+6. **Error handling**: Continue with local cleanup if remote deletion fails
+
+## Files to Modify/Create
+
+| File | Action | Description |
+|------|--------|-------------|
+| `src/types.ts` | MODIFY | Add `CleanupOptions` and `CleanupResult` interfaces |
+| `src/core/cleanup.ts` | CREATE | Core cleanup implementation |
+| `src/tools/cleanup.ts` | CREATE | Tool definition for plugin mode |
+| `src/cli.ts` | MODIFY | Add cleanup command registration |
+| `src/index.ts` | MODIFY | Export cleanup tool |
+| `tests/cleanup.test.ts` | CREATE | Unit tests |
+
+---
+
+## Implementation Details
+
+### 1. TypeScript Interfaces(`src/types.ts`)
+
+Add after `WorktreeInfo` interface (around line 98):
+
+```typescript
+/**
+ * Options for cleaning up archive tags.
+ */
+export interface CleanupOptions {
+  /** Skip confirmation prompts. */
+  force?: boolean;
+  /** 
+   * Remote name to push deletions to.
+   * - If string: use specified remote (error if doesn't exist)
+   * - If undefined: use first available remote from git remote -v
+   * - If false: only local cleanup (--no-remote flag)
+   */
+  remote?: string | false;
+}
+
+/**
+ * Result returned after attempting to cleanup archive tags.
+ */
+export interface CleanupResult {
+  /** Whether the cleanup succeeded. */
+  success: boolean;
+  /** Error message if the cleanup failed. */
+  error?: string;
+  /** Summary message for the user. */
+  instructions?: string;
+  /** Number of local tags deleted. */
+  localTagsDeleted: number;
+  /** Number of remote tags deleted. */
+  remoteTagsDeleted: number;
+  /** Names of tags that were deleted locally. */
+  localTagNames: string[];
+  /** Names of tags deleted from remote. */
+  remoteTagNames: string[];
+  /** Tags that failed remote deletion. */
+  remoteTagErrors: Array<{ tag: string; error: string }>;
+  /** Available remotes discovered. */
+  availableRemotes: string[];
+}
+```
+
+---
+
+### 2. Core Implementation (`src/core/cleanup.ts`)
+
+Create new file with the following functions:
+
+#### Helper Functions
+
+```typescript
+import * as readline from "node:readline";
+import chalk from 'chalk';
+import type { CleanupOptions, CleanupResult } from "../types";
+import { runCommand } from "./utils";
+
+/**
+ * Prompts the user for confirmation on the terminal.
+ */
+async function promptUser(question: string): Promise<string> {
+  const rl = readline.createInterface({
+    input: process.stdin,
+    output: process.stdout,
+  });
+  return new Promise((resolve) => {
+    rl.question(question, (answer) => {
+      rl.close();
+      resolve(answer);
+    });
+  });
+}
+
+/**
+ * Lists all archive tags matching the pattern archive/*.
+ */
+export async function listArchiveTags(): Promise<string[]> {
+  const { stdout } = await runCommand(["git", "tag", "-l", "archive/*"]);
+  return stdout.split("\n").filter(Boolean);
+}
+
+/**
+ * Gets the list of available git remotes.
+ */
+export async function getAvailableRemotes(): Promise<string[]> {
+  const { stdout } = await runCommand(["git", "remote"]);
+  return stdout.split("\n").filter(Boolean);
+}
+
+/**
+ * Deletes a local git tag.
+ */
+async function deleteLocalTag(tagName: string): Promise<boolean> {
+  const result = await runCommand(["git", "tag", "-d", tagName]);
+  return result.ok;
+}
+
+/**
+ * Deletes a tag from a remote repository.
+ */
+async function deleteRemoteTag(tagName: string, remoteName: string): Promise<{ ok: boolean; error: string }> {
+  const result = await runCommand(["git", "push", remoteName, "--delete", tagName]);
+  return {
+    ok: result.ok,
+    error: result.ok ? "" : result.stderr,
+  };
+}
+```
+
+#### Main Function
+
+```typescript
+/**
+ * Cleans up archive tags from local and optionally remote repositories.
+ *
+ * Archive tags have the format: archive/<branch-name>-<timestamp>
+ * These are created by the close command to preserve branch state before deletion.
+ *
+ * @param options Cleanup configuration including force mode and remote settings.
+ * @returns Result with counts and details of deleted tags.
+ */
+export async function cleanupArchiveTags(options: CleanupOptions = {}): Promise<CleanupResult> {
+  const { force = false, remote } = options;
+
+  // Get available remotes and archive tags first
+  const availableRemotes = await getAvailableRemotes();
+  const archiveTags = await listArchiveTags();
+
+  // Determine whether to push to remote and which remote to use:
+  // - remote === false: --no-remote flag, local-only mode
+  // - remote === string: use specified remote (error if doesn't exist)
+  // - remote === undefined: use first available remote
+  const shouldPushToRemote = remote !== false;
+
+  let remoteToDeleteFrom: string | undefined;
+
+  if (shouldPushToRemote) {
+    if (typeof remote === "string") {
+      // User specified a remote - validate it exists
+      if (!availableRemotes.includes(remote)) {
+        return {
+          success: false,
+          error: `Error: Remote '${remote}' not found. Available remotes: ${availableRemotes.join(", ") || "none"}`,
+          localTagsDeleted: 0,
+          remoteTagsDeleted: 0,
+          localTagNames: [],
+          remoteTagNames: [],
+          remoteTagErrors: [],
+          availableRemotes,
+        };
+      }
+      remoteToDeleteFrom = remote;
+    } else {
+      // remote === undefined, use first available
+      remoteToDeleteFrom = availableRemotes[0];
+    }
+  }
+
+  if (archiveTags.length === 0) {
+    return {
+      success: true,
+      instructions: chalk.dim("No archive tags found."),
+      localTagsDeleted: 0,
+      remoteTagsDeleted: 0,
+      localTagNames: [],
+      remoteTagNames: [],
+      remoteTagErrors: [],
+      availableRemotes,
+    };
+  }
+
+  // Confirmation prompt (unless --force)
+  if (!force) {
+    const tagCount = archiveTags.length;
+    const tagWord = tagCount === 1 ? "tag" : "tags";
+    console.log(chalk.yellow(`Found ${tagCount} archive ${tagWord}.`));
+
+    if (shouldPushToRemote && remoteToDeleteFrom) {
+      console.log(chalk.dim(`Remote deletions will use: ${remoteToDeleteFrom}`));
+    } else if (shouldPushToRemote && !remoteToDeleteFrom) {
+      console.log(chalk.dim("No remotes configured. Only local cleanup will be performed."));
+    }
+
+    const answer = await promptUser(chalk.bold("\nProceed with cleanup? (y/N): "));
+    if (answer.toLowerCase() !== "y" && answer.toLowerCase() !== "yes") {
+      return {
+        success: false,
+        error: "Cleanup cancelled by user",
+        localTagsDeleted: 0,
+        remoteTagsDeleted: 0,
+        localTagNames: [],
+        remoteTagNames: [],
+        remoteTagErrors: [],
+        availableRemotes,
+      };
+    }
+  }
+
+  const localTagNames: string[] = [];
+  const remoteTagNames: string[] = [];
+  const remoteTagErrors: Array<{ tag: string; error: string }> = [];
+
+  // Delete local tags
+  for (const tag of archiveTags) {
+    const deleted = await deleteLocalTag(tag);
+    if (deleted) {
+      localTagNames.push(tag);
+    }
+  }
+
+  // Delete from remote (if remote is specified and exists)
+  if (shouldPushToRemote && remoteToDeleteFrom) {
+    for (const tag of localTagNames) {
+      const result = await deleteRemoteTag(tag, remoteToDeleteFrom);
+      if (result.ok) {
+        remoteTagNames.push(tag);
+      } else {
+        // Continue with local cleanup even if remote fails
+        remoteTagErrors.push({ tag, error: result.error });
+      }
+    }
+  }
+
+  // Build instructions message
+  const instructionsArr: string[] = [];
+  if (localTagNames.length > 0) {
+    const word = localTagNames.length === 1 ? "tag" : "tags";
+    instructionsArr.push(chalk.green(`Deleted ${localTagNames.length} local archive ${word}.`));
+  }
+  if (remoteTagNames.length > 0) {
+    const word = remoteTagNames.length === 1 ? "tag" : "tags";
+    instructionsArr.push(chalk.green(`Deleted ${remoteTagNames.length} remote archive ${word}.`));
+  }
+  if (remoteTagErrors.length > 0) {
+    const word = remoteTagErrors.length === 1 ? "tag" : "tags";
+    instructionsArr.push(chalk.yellow(`Failed to delete ${remoteTagErrors.length} remote ${word} (local cleanup continued).`));
+  }
+
+  return {
+    success: true,
+    instructions: instructionsArr.join("\n"),
+    localTagsDeleted: localTagNames.length,
+    remoteTagsDeleted: remoteTagNames.length,
+    localTagNames,
+    remoteTagNames,
+    remoteTagErrors,
+    availableRemotes,
+  };
+}
+```
+
+---
+
+### 3. Tool Definition (`src/tools/cleanup.ts`)
+
+Create new file:
+
+```typescript
+import { tool } from "@opencode-ai/plugin";
+import { cleanupArchiveTags } from "../core/cleanup";
+
+/**
+ * OpenCode tool definition for cleaning up archive tags.
+ *
+ * Deletes archive tags (format: archive/*) from local and remote repositories.
+ * Used to clean up recovery tags created by the close command.
+ */
+export const cleanupTool = tool({
+  description: "Delete all archive tags from local and optionally remote repository",
+  args: {
+    remote: tool.schema.union([
+      tool.schema.string().describe("Remote name to push deletions to. Error if doesn't exist."),
+      tool.schema.literal(false).describe("Only delete local tags, don't push to remote."),
+    ]).optional().describe("Remote handling: string=specific remote, false=local-only, undefined=first available remote"),
+  },
+  async execute(args, context) {
+    // In plugin mode, we skip confirmation (force=true)
+    const result = await cleanupArchiveTags({
+      force: true,
+      remote: args.remote,
+    });
+
+    if (!result.success) {
+      return result.error!;
+    }
+
+    return result.instructions ?? `Deleted ${result.localTagsDeleted} local tags.`;
+  },
+});
+```
+
+---
+
+### 4. CLI Command (`src/cli.ts`)
+
+Add import after line 5:
+
+```typescript
+import { cleanupArchiveTags } from "./core/cleanup";
+```
+
+Add command after line 69 (after close command):
+
+```typescript
+program
+  .command("cleanup")
+  .description("Delete all archive tags from local and remote")
+  .option("-f, --force", "Skip confirmation prompts", false)
+  .option("-r, --remote <remote>", "Remote name to push deletions to (default: first remote from git remote -v)")
+  .option("--no-remote", "Only delete local tags, skip remote")
+  .action(async (options: { force: boolean; remote?: string|boolean }) => {
+    try {
+      const result = await cleanupArchiveTags({
+        force: options.force,
+        remote: options.remote,
+      });
+
+      if (result.success) {
+        console.log(result.instructions);
+      } else {
+        console.error(`Failed: ${result.error}`);
+        process.exit(1);
+      }
+    } catch (error) {
+      console.error(`Error: ${error}`);
+      process.exit(1);
+    }
+  });
+```
+
+---
+
+### 5. Index Export (`src/index.ts`)
+
+Add import after line 3:
+
+```typescript
+import { cleanupTool } from "./tools/cleanup";
+```
+
+Update return object (line 22-25):
+
+```typescript
+    tool: {
+      "multi-model-open": openTool,
+      "multi-model-close": closeTool,
+      "multi-model-cleanup": cleanupTool,
+    },
+```
+
+Update exports (line30):
+
+```typescript
+export { openTool, closeTool, cleanupTool };
+```
+
+---
+
+## Usage Examples
+
+### CLI Usage
+
+```bash
+# Interactive (shows confirmation prompt, uses first remote from git remote -v)
+opencode-multi-model cleanup
+
+# Skip confirmation
+opencode-multi-model cleanup --force
+
+# Use specific remote
+opencode-multi-model cleanup --remote upstream
+
+# Only local cleanup (don't push to remote)
+opencode-multi-model cleanup --no-remote
+
+# Combined options
+opencode-multi-model cleanup -f --remote upstream
+```
+
+### Tool Usage (OpenCode Plugin)
+
+```typescript
+// Local-only cleanup (don't push to remote)
+await multi-model-cleanup({ remote: false });
+
+// Use first available remote (default behavior)
+await multi-model-cleanup({ remote: undefined });
+
+// Specify a remote
+await multi-model-cleanup({ remote: "upstream" });
+```
+
+---
+
+## Git Commands Used
+
+| Command | Purpose |
+|---------|---------|
+| `git tag -l "archive/*"` | List all archive tags |
+| `git remote` | Get available remotes |
+| `git tag -d <name>` | Delete local tag |
+| `git push <remote> --delete <tag>` | Delete remote tag |
+
+---
+
+## Verification
+
+After implementation, verify with:
+
+1. **Build**: `bun run build` or `bun run typecheck`
+2. **Unit tests**: `bun test tests/cleanup.test.ts`
+3. **Manual test**:
+   ```bash
+   # Create some archive tags for testing
+   git tag archive/test-branch-1-2024-01-01T00-00-00-000Z
+   git tag archive/test-branch-2-2024-01-02T00-00-00-000Z
+   
+   # Run cleanup
+   bun run src/cli.ts cleanup
+   
+   # Verify tags are deleted
+   git tag -l "archive/*"
+   ```
+
+---
+
+## Test Cases
+
+Create `tests/cleanup.test.ts` with:
+
+1. No archive tags found - returns success with message
+2. User cancels confirmation - returns success=false
+3. Force mode skips confirmation
+4. **--no-remote flag (remote=false) - only local cleanup, no remote push**
+5. Remote deletion failure continues local cleanup
+6. **Dynamic remote detection - remote=undefined uses first available remote**
+7. **Remote name validation - uses specified remote if it exists**
+8. **Remote error - returns error if specified remote doesn't exist**
+9. No remotes configured - only local cleanup

.opencode/tools/multi-model.ts

@@ -1,6 +1,7 @@
 // Re-export open and close tools for project-level use via relative paths.
 // For published package usage, change imports to "@username/opencode-multi-model".
-import { openTool } from "../../src/tools/open";
-import { closeTool } from "../../src/tools/close";
 
-export { openTool as open, closeTool as close };
+import { closeTool } from "../../src/tools/close";
+import { openTool } from "../../src/tools/open";
+
+export { closeTool as close, openTool as open };

.opencode/tsconfig.json

@@ -18,9 +18,7 @@
     "noUncheckedIndexedAccess": true,
     "noImplicitOverride": true,
 
-    "types": [
-      "bun-types"
-    ]
+    "types": ["bun-types"]
   },
   "include": ["**/*.ts", "**/*.tsx"]
-}
+}

.vscode/launch.json

@@ -0,0 +1,25 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "type": "node",
+      "request": "launch",
+      "name": "Open Multi-Model Session",
+      "runtimeExecutable": "bun",
+      "program": "${workspaceFolder}/src/cli.ts",
+      "args": ["open", "test/session1", "--models", "openai/gpt-5.2"],
+      "cwd": "${workspaceFolder}",
+      "console": "integratedTerminal"
+    },
+    {
+      "type": "node",
+      "request": "launch",
+      "name": "Close Multi-Model Session",
+      "runtimeExecutable": "bun",
+      "program": "${workspaceFolder}/src/cli.ts",
+      "args": ["close", "test/session1"],
+      "cwd": "${workspaceFolder}",
+      "console": "integratedTerminal"
+    }
+  ]
+}

.vscode/settings.json

@@ -0,0 +1,16 @@
+{
+  // The path to the `bun` executable.
+  "bun.runtime": "/path/to/bun",
+
+  // If support for Bun should be added to the default "JavaScript Debug Terminal".
+  "bun.debugTerminal.enabled": true,
+
+  // If the debugger should stop on the first line of the program.
+  "bun.debugTerminal.stopOnEntry": false,
+
+  // Glob pattern to find test files. Defaults to the value shown below.
+  "bun.test.filePattern": "**/*{.test.,.spec.,_test_,_spec_}{js,ts,tsx,jsx,mts,cts,cjs,mjs}",
+
+  // The custom script to call for testing instead of `bun test`
+  "bun.test.customScript": "bun test"
+}

README.md

@@ -13,7 +13,7 @@ Add to your OpenCode config (`opencode.json`):
 
 ```json
 {
-  "plugin": ["@bendtherules/opencode-multi-model"]
+  "plugin": ["opencode-multi-model"]
 }
 ```
 
@@ -21,10 +21,10 @@ Add to your OpenCode config (`opencode.json`):
 
 ```bash
 # Using bunx (no install)
-bunx @bendtherules/opencode-multi-model open my-session -m openai/gpt-5.2 anthropic/claude-3-5-sonnet
+bunx opencode-multi-model open my-session -m openai/gpt-5.2 anthropic/claude-3-5-sonnet
 
 # Or install globally
-bun install -g @bendtherules/opencode-multi-model
+bun install -g opencode-multi-model
 opencode-multi-model open my-session -m openai/gpt-5.2
 ```
 
@@ -34,7 +34,7 @@ If you installed it via bun and want to use it as a project tool, import it from
 
 ```typescript
 // .opencode/tools/multi-model.ts
-import { openTool as open, closeTool as close } from "@bendtherules/opencode-multi-model"
+import { openTool as open, closeTool as close } from "opencode-multi-model"
 export { open, close }
 ```
 
@@ -118,6 +118,79 @@ opencode-multi-model open my-session -m openai/gpt-5.2 -b kilo
 
 Priority: CLI flag > Environment variable > Default ("opencode")
 
+## CLI Reference
+
+### `open` - Create a new multi-model tmux session
+
+```bash
+opencode-multi-model open <session-name> [options]
+```
+
+**Arguments:**
+- `<session-name>` - Name for the tmux session (required)
+
+**Options:**
+| Option | Description |
+|--------|-------------|
+| `-m, --models <models...>` | Model IDs to launch (space-separated) |
+| `-b, --binary <binary>` | Binary to use (opencode or kilo). Defaults to env var `OPENCODE_MULTI_MODEL_BINARY` or 'opencode' |
+
+### `close` - Close a multi-model tmux session
+
+```bash
+opencode-multi-model close <session-name> [options]
+```
+
+**Arguments:**
+- `<session-name>` - Name of the tmux session to close (required)
+
+**Options:**
+| Option | Description |
+|--------|-------------|
+| `--keep-worktrees` | Do not remove worktrees and delete branches |
+| `--no-tags` | Do not create archive tags before deleting branches |
+| `-f, --force` | Skip confirmation prompts |
+
+### Global Options
+
+| Option | Description |
+|--------|-------------|
+| `-h, --help` | Display help information |
+| `-V, --version` | Display version number |
+
+## How it works
+
+### `open` command
+
+The `open` command performs the following steps:
+
+1. **Validation**: Checks that session name andmodels are provided, no duplicate models exist, and verifies git repo, tmux, and binary are available
+
+2. **Model verification**: Validates models against `opencode models` output to ensure only valid model IDs are used
+
+3. **Git worktree creation**: For each model, creates:
+   - A git worktree at `~/.local/share/opencode/multi-model/<session>/<model>/`
+   - A branch named `opencode/<session>/<model>`
+
+4. **Tmux session**: Creates a tmux session with one window per model, each window's working directory set to its corresponding worktree
+
+5. **Launch**: Sends the launch command to each window to start the binary with the specified model
+
+### `close` command
+
+The `close` command performs the following steps:
+
+1. **Kill tmux session**: Terminates the tmux session if it exists
+
+2. **Worktree discovery**: Finds all worktrees under `~/.local/share/opencode/multi-model/<session>/`
+
+3. **Worktree cleanup** (unless `--keep-worktrees`):
+   - Removes each gitworktree
+   - Creates an archive tag (unless `--no-tags`): `archive/<branch>-<timestamp>` for recovery
+   - Deletes the associated branches
+
+4. **Directory cleanup**: Removes the base session directory
+
 ## Requirements
 
 - tmux
@@ -133,6 +206,9 @@ For local development and testing without publishing:
 # Install dependencies
 bun install
 
+# Setup git hooks
+bun run setup
+
 # Build
 bun run build
 
@@ -153,7 +229,7 @@ bun dist/cli.js close test-session
 │   ├── types.ts               # Shared TypeScript types
 │   ├── core/
 │   │   ├── index.ts           # Core exports
-│   │   ├── launch.ts          # Launch session logic
+│   │   ├── open.ts            # Launch session logic
 │   │   ├── close.ts           # Close session logic
 │   │   └── utils.ts           # Helper functions
 │   └── tools/
@@ -166,6 +242,19 @@ bun dist/cli.js close test-session
 └── README.md
 ```
 
+## Local code coverage
+
+The test suite can generate a coverage report locally.
+
+```bash
+# Run tests with coverage (HTML report generated in ./coverage)
+  npm run coverage   # or: bun run coverage
+# Open the HTML report
+ open coverage/index.html   # macOS
+```
+
+The `coverage` directory is ignored by Git but can be inspected to see which lines are exercised.
+
 ## License
 
 MIT

biome.json

@@ -0,0 +1,50 @@
+{
+  "$schema": "https://biomejs.dev/schemas/2.4.8/schema.json",
+  "vcs": {
+    "enabled": true,
+    "clientKind": "git",
+    "useIgnoreFile": true
+  },
+  "files": {
+    "includes": ["**", "!!**/dist"]
+  },
+  "formatter": {
+    "enabled": true,
+    "indentStyle": "space",
+    "indentWidth": 2
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true,
+      "style": {
+        "noNonNullAssertion": "off"
+      },
+      "suspicious": {
+        "noExplicitAny": "off"
+      },
+      "correctness": {
+        "noUnusedImports": "warn",
+        "noUnusedFunctionParameters": "warn",
+        "noUnusedVariables": "warn",
+        "noConstructorReturn": "warn"
+      },
+      "complexity": {
+        "useLiteralKeys": "warn"
+      }
+    }
+  },
+  "javascript": {
+    "formatter": {
+      "quoteStyle": "double"
+    }
+  },
+  "assist": {
+    "enabled": true,
+    "actions": {
+      "source": {
+        "organizeImports": "on"
+      }
+    }
+  }
+}

bun.lock

@@ -6,15 +6,36 @@
       "name": "@username/opencode-multi-model",
       "dependencies": {
         "@opencode-ai/plugin": "^1.2.27",
+        "chalk": "^5.3.0",
         "commander": "^12.0.0",
       },
       "devDependencies": {
+        "@biomejs/biome": "^2.4.8",
         "@types/bun": "^1.3.10",
         "@types/node": "^25.5.0",
+        "typescript": "^5.9.3",
       },
     },
   },
   "packages": {
+    "@biomejs/biome": ["@biomejs/biome@2.4.8", "", { "optionalDependencies": { "@biomejs/cli-darwin-arm64": "2.4.8", "@biomejs/cli-darwin-x64": "2.4.8", "@biomejs/cli-linux-arm64": "2.4.8", "@biomejs/cli-linux-arm64-musl": "2.4.8", "@biomejs/cli-linux-x64": "2.4.8", "@biomejs/cli-linux-x64-musl": "2.4.8", "@biomejs/cli-win32-arm64": "2.4.8", "@biomejs/cli-win32-x64": "2.4.8" }, "bin": { "biome": "bin/biome" } }, "sha512-ponn0oKOky1oRXBV+rlSaUlixUxf1aZvWC19Z41zBfUOUesthrQqL3OtiAlSB1EjFjyWpn98Q64DHelhA6jNlA=="],
+
+    "@biomejs/cli-darwin-arm64": ["@biomejs/cli-darwin-arm64@2.4.8", "", { "os": "darwin", "cpu": "arm64" }, "sha512-ARx0tECE8I7S2C2yjnWYLNbBdDoPdq3oyNLhMglmuctThwUsuzFWRKrHmIGwIRWKz0Mat9DuzLEDp52hGnrxGQ=="],
+
+    "@biomejs/cli-darwin-x64": ["@biomejs/cli-darwin-x64@2.4.8", "", { "os": "darwin", "cpu": "x64" }, "sha512-Jg9/PsB9vDCJlANE8uhG7qDhb5w0Ix69D7XIIc8IfZPUoiPrbLm33k2Ig3NOJ/7nb3UbesFz3D1aDKm9DvzjhQ=="],
+
+    "@biomejs/cli-linux-arm64": ["@biomejs/cli-linux-arm64@2.4.8", "", { "os": "linux", "cpu": "arm64" }, "sha512-5CdrsJct76XG2hpKFwXnEtlT1p+4g4yV+XvvwBpzKsTNLO9c6iLlAxwcae2BJ7ekPGWjNGw9j09T5KGPKKxQig=="],
+
+    "@biomejs/cli-linux-arm64-musl": ["@biomejs/cli-linux-arm64-musl@2.4.8", "", { "os": "linux", "cpu": "arm64" }, "sha512-Zo9OhBQDJ3IBGPlqHiTISloo5H0+FBIpemqIJdW/0edJ+gEcLR+MZeZozcUyz3o1nXkVA7++DdRKQT0599j9jA=="],
+
+    "@biomejs/cli-linux-x64": ["@biomejs/cli-linux-x64@2.4.8", "", { "os": "linux", "cpu": "x64" }, "sha512-PdKXspVEaMCQLjtZCn6vfSck/li4KX9KGwSDbZdgIqlrizJ2MnMcE3TvHa2tVfXNmbjMikzcfJpuPWH695yJrw=="],
+
+    "@biomejs/cli-linux-x64-musl": ["@biomejs/cli-linux-x64-musl@2.4.8", "", { "os": "linux", "cpu": "x64" }, "sha512-Gi8quv8MEuDdKaPFtS2XjEnMqODPsRg6POT6KhoP+VrkNb+T2ywunVB+TvOU0LX1jAZzfBr+3V1mIbBhzAMKvw=="],
+
+    "@biomejs/cli-win32-arm64": ["@biomejs/cli-win32-arm64@2.4.8", "", { "os": "win32", "cpu": "arm64" }, "sha512-LoFatS0tnHv6KkCVpIy3qZCih+MxUMvdYiPWLHRri7mhi2vyOOs8OrbZBcLTUEWCS+ktO72nZMy4F96oMhkOHQ=="],
+
+    "@biomejs/cli-win32-x64": ["@biomejs/cli-win32-x64@2.4.8", "", { "os": "win32", "cpu": "x64" }, "sha512-vAn7iXDoUbqFXqVocuq1sMYAd33p8+mmurqJkWl6CtIhobd/O6moe4rY5AJvzbunn/qZCdiDVcveqtkFh1e7Hg=="],
+
     "@opencode-ai/plugin": ["@opencode-ai/plugin@1.2.27", "", { "dependencies": { "@opencode-ai/sdk": "1.2.27", "zod": "4.1.8" } }, "sha512-h+8Bw9v9nghMg7T+SUCTzxlIhOrsTqXW7U0HVLGQST5DjbN7uyCUM51roZWZ8LRjGxzbzFhvPnY1bj8i+ioZyw=="],
 
     "@opencode-ai/sdk": ["@opencode-ai/sdk@1.2.27", "", {}, "sha512-Wk0o/I+Fo+wE3zgvlJDs8Fb67KlKqX0PrV8dK5adSDkANq6r4Z25zXJg2iOir+a8ntg3rAcpel1OY4FV/TwRUA=="],
@@ -25,8 +46,12 @@
 
     "bun-types": ["bun-types@1.3.11", "", { "dependencies": { "@types/node": "*" } }, "sha512-1KGPpoxQWl9f6wcZh57LvrPIInQMn2TQ7jsgxqpRzg+l0QPOFvJVH7HmvHo/AiPgwXy+/Thf6Ov3EdVn1vOabg=="],
 
+    "chalk": ["chalk@5.6.2", "", {}, "sha512-7NzBL0rN6fMUW+f7A6Io4h40qQlG+xGmtMxfbnH/K7TAtt8JQWVQK+6g0UXKMeVJoyV5EkkNsErQ8pVD3bLHbA=="],
+
     "commander": ["commander@12.1.0", "", {}, "sha512-Vw8qHK3bZM9y/P10u3Vib8o/DdkvA2OtPtZvD871QKjy74Wj1WSKFILMPRPSdUSx5RFK1arlJzEtA4PkFgnbuA=="],
 
+    "typescript": ["typescript@5.9.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw=="],
+
     "undici-types": ["undici-types@7.18.2", "", {}, "sha512-AsuCzffGHJybSaRrmr5eHr81mwJU3kjw6M+uprWvCXiNeN9SOGwQ3Jn8jb8m3Z6izVgknn1R0FTCEAP2QrLY/w=="],
 
     "zod": ["zod@4.1.8", "", {}, "sha512-5R1P+WwQqmmMIEACyzSvo4JXHY5WiAFHRMg+zBZKgKS+Q1viRa0C1hmUKtHltoIFKtIdki3pRxkmpP74jnNYHQ=="],

package.json

@@ -1,11 +1,11 @@
 {
-  "name": "@bendtherules/opencode-multi-model",
-  "version": "0.0.2",
+  "name": "opencode-multi-model",
+  "version": "0.0.11",
   "description": "Launch multiple AI models in tmux sessions - OpenCode Plugin, CLI, and Project Tool",
   "type": "module",
   "main": "./dist/index.js",
   "bin": {
-    "opencode-multi-model": "./dist/cli.js"
+    "opencode-multi-model": "dist/cli.js"
   },
   "exports": {
     ".": "./dist/index.js",
@@ -19,16 +19,25 @@
   "scripts": {
     "build": "bun build src/index.ts src/cli.ts --outdir dist --target bun --format esm",
     "test": "bun test",
+    "coverage": "bun test --coverage",
     "prepublishOnly": "bun run build",
-    "release": "bash ./scripts/release.sh"
+    "release": "bash ./scripts/release.sh",
+    "setup": "bash ./scripts/setup.sh",
+    "lint": "biome check .",
+    "lint:fix": "biome check . --fix",
+    "format": "biome format . --write",
+    "typecheck": "tsc --noEmit"
   },
   "dependencies": {
+    "chalk": "^5.3.0",
     "@opencode-ai/plugin": "^1.2.27",
     "commander": "^12.0.0"
   },
   "devDependencies": {
+    "@biomejs/biome": "^2.4.8",
     "@types/bun": "^1.3.10",
-    "@types/node": "^25.5.0"
+    "@types/node": "^25.5.0",
+    "typescript": "^5.9.3"
   },
   "keywords": [
     "opencode",

scripts/setup.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Setup script for development environment
+
+echo "Setting up git hooks..."
+git config core.hooksPath .githooks
+
+echo "Setup complete!"

src/cli.ts

@@ -1,7 +1,8 @@
 #!/usr/bin/env bun
 import { Command } from "commander";
-import { launchMultiModel } from "./core/launch";
+import { cleanupMultiModel } from "./core/cleanup";
 import { closeMultiModel } from "./core/close";
+import { openMultiModel } from "./core/open";
 import { getBinaryName } from "./core/utils";
 
 const program = new Command();
@@ -15,59 +16,100 @@ program
   .command("open")
   .description("Create a new multi-model tmux session")
   .argument("<session-name>", "Name for the tmux session")
-  .option("-m, --models <models...>", "Model IDs to launch (space-separated)", [])
-  .option("-b, --binary <binary>", "Binary to use (opencode or kilo). Defaults to env var OPENCODE_MULTI_MODEL_BINARY or 'opencode'")
-  .action(async (sessionName: string, options: { models: string[]; binary?: string }) => {
-    try {
-      const binaryName = options.binary || getBinaryName();
+  .option(
+    "-m, --models <models...>",
+    "Model IDs to launch (space-separated)",
+    [],
+  )
+  .option(
+    "-b, --binary <binary>",
+    "Binary to use (opencode or kilo). Defaults to env var OPENCODE_MULTI_MODEL_BINARY or 'opencode'",
+  )
+  .action(
+    async (
+      sessionName: string,
+      options: { models: string[]; binary?: string },
+    ) => {
+      try {
+        const binaryName = options.binary || getBinaryName();
 
-      const result = await launchMultiModel({
-        sessionName,
-        models: options.models,
-        binaryName,
-        mode: "cli",
-      });
+        const result = await openMultiModel({
+          sessionName,
+          models: options.models,
+          binaryName,
+          mode: "cli",
+        });
 
-      if (result.success) {
-        console.log(result.instructions || `Created session: ${result.sessionName}`);
-      } else {
-        console.error(`Failed: ${result.error}`);
+        if (result.success) {
+          console.log(
+            result.instructions || `Created session: ${result.sessionName}`,
+          );
+        } else {
+          console.error(`Failed: ${result.error}`);
+          process.exit(1);
+        }
+      } catch (error) {
+        console.error(`Error: ${error}`);
         process.exit(1);
       }
-    } catch (error) {
-      console.error(`Error: ${error}`);
-      process.exit(1);
-    }
-  });
+    },
+  );
 
 program
   .command("close")
   .description("Close a multi-model tmux session")
   .argument("<session-name>", "Name of the tmux session to close")
-  .option("-c, --cleanup-worktrees", "Remove worktrees and delete branches", true)
+  .option(
+    "--keep-worktrees",
+    "Do not remove worktrees and delete branches",
+    false,
+  )
+  .option("--no-tags", "Create archive tags before deleting branches")
   .option("-f, --force", "Skip confirmation prompts", false)
-  .action(async (sessionName: string, options: { cleanupWorktrees: boolean; force: boolean }) => {
+  .action(
+    async (
+      sessionName: string,
+      options: { keepWorktrees: boolean; force: boolean; tags: boolean },
+    ) => {
+      try {
+        const result = await closeMultiModel({
+          sessionName,
+          cleanupWorktrees: !options.keepWorktrees,
+          force: options.force,
+          createArchiveTags: options.tags,
+        });
+
+        if (result.success) {
+          console.log(result.instructions);
+        } else {
+          console.error(`Failed: ${result.error}`);
+          process.exit(1);
+        }
+      } catch (error) {
+        console.error(`Error: ${error}`);
+        process.exit(1);
+      }
+    },
+  );
+
+program
+  .command("cleanup")
+  .description("Delete all archive tags from local and remote")
+  .option("-f, --force", "Skip confirmation prompts", false)
+  .option(
+    "-r, --remote <remote>",
+    "Remote name to push deletions to (default: first remote from git remote -v)",
+  )
+  .option("--no-remote", "Only delete local tags, skip remote")
+  .action(async (options: { force: boolean; remote?: string | boolean }) => {
     try {
-      const result = await closeMultiModel({
-        sessionName,
-        cleanupWorktrees: options.cleanupWorktrees,
+      const result = await cleanupMultiModel({
         force: options.force,
+        remote: options.remote === true ? undefined : options.remote,
       });
 
       if (result.success) {
-        console.log(`Closed session: ${result.sessionName}`);
-        if (result.cleanupPerformed) {
-          console.log(`  Removed ${result.worktreesRemoved?.length || 0} worktrees`);
-          if (result.tagsCreated && result.tagsCreated.length > 0) {
-            console.log(`  Created backup tags: ${result.tagsCreated.join(", ")}`);
-          }
-          if (result.warnings && result.warnings.length > 0) {
-            console.log(`  Warnings: ${result.warnings.join("; ")}`);
-          }
-          if (result.branchesDeleted && result.branchesDeleted.length > 0) {
-            console.log(`  Deleted ${result.branchesDeleted.length} branches`);
-          }
-        }
+        console.log(result.instructions);
       } else {
         console.error(`Failed: ${result.error}`);
         process.exit(1);

src/core/cleanup.ts

@@ -0,0 +1,220 @@
+import * as readline from "node:readline";
+import chalk from "chalk";
+import type { CleanupOptions, CleanupResult } from "../types";
+import { runCommand } from "./utils";
+
+/**
+ * Prompts the user for confirmation on the terminal.
+ */
+async function promptUser(question: string): Promise<string> {
+  const rl = readline.createInterface({
+    input: process.stdin,
+    output: process.stdout,
+  });
+  return new Promise((resolve) => {
+    rl.question(question, (answer) => {
+      rl.close();
+      resolve(answer);
+    });
+  });
+}
+
+/**
+ * Lists all archive tags matching the pattern archive/*.
+ */
+export async function listArchiveTags(): Promise<string[]> {
+  const { stdout } = await runCommand(["git", "tag", "-l", "archive/*"]);
+  return stdout.split("\n").filter(Boolean);
+}
+
+/**
+ * Gets the list of available git remotes.
+ */
+export async function getAvailableRemotes(): Promise<string[]> {
+  const { stdout } = await runCommand(["git", "remote"]);
+  return stdout.split("\n").filter(Boolean);
+}
+
+/**
+ * Deletes a local git tag.
+ */
+async function deleteLocalTag(tagName: string): Promise<boolean> {
+  const result = await runCommand(["git", "tag", "-d", tagName]);
+  return result.ok;
+}
+
+/**
+ * Deletes a tag from a remote repository.
+ */
+async function deleteRemoteTag(
+  tagName: string,
+  remoteName: string,
+): Promise<{ ok: boolean; error: string }> {
+  const result = await runCommand([
+    "git",
+    "push",
+    remoteName,
+    "--delete",
+    tagName,
+  ]);
+  return {
+    ok: result.ok,
+    error: result.ok ? "" : result.stderr,
+  };
+}
+
+/**
+ * Cleans up archive tags from local and optionally remote repositories.
+ *
+ * Archive tags have the format: archive/<branch-name>-<timestamp>
+ * These are created by the close command to preserve branch state before deletion.
+ *
+ * @param options Cleanup configuration including force mode and remote settings.
+ * @returns Result with counts and details of deleted tags.
+ */
+export async function cleanupMultiModel(
+  options: CleanupOptions = {},
+): Promise<CleanupResult> {
+  const { force = false, remote } = options;
+
+  // Get available remotes and archive tags first
+  const availableRemotes = await getAvailableRemotes();
+  const archiveTags = await listArchiveTags();
+
+  // Determine whether to push to remote and which remote to use:
+  // - remote === false: --no-remote flag, local-only mode
+  // - remote === string: use specified remote (error if doesn't exist)
+  // - remote === undefined: use first available remote
+  const shouldPushToRemote = remote !== false;
+
+  let remoteToDeleteFrom: string | undefined;
+
+  if (shouldPushToRemote) {
+    if (typeof remote === "string") {
+      // User specified a remote - validate it exists
+      if (!availableRemotes.includes(remote)) {
+        return {
+          success: false,
+          error: `Error: Remote '${remote}' not found. Available remotes: ${availableRemotes.join(", ") || "none"}`,
+          localTagsDeleted: 0,
+          remoteTagsDeleted: 0,
+          localTagNames: [],
+          remoteTagNames: [],
+          remoteTagErrors: [],
+          availableRemotes,
+        };
+      }
+      remoteToDeleteFrom = remote;
+    } else {
+      // remote === undefined, use first available
+      remoteToDeleteFrom = availableRemotes[0];
+    }
+  }
+
+  if (archiveTags.length === 0) {
+    return {
+      success: true,
+      instructions: chalk.dim("No archive tags found."),
+      localTagsDeleted: 0,
+      remoteTagsDeleted: 0,
+      localTagNames: [],
+      remoteTagNames: [],
+      remoteTagErrors: [],
+      availableRemotes,
+    };
+  }
+
+  // Confirmation prompt (unless --force)
+  if (!force) {
+    const tagCount = archiveTags.length;
+    const tagWord = tagCount === 1 ? "tag" : "tags";
+    console.log(chalk.yellow(`Found ${tagCount} archive ${tagWord}.`));
+
+    if (shouldPushToRemote && remoteToDeleteFrom) {
+      console.log(
+        chalk.dim(`Remote deletions will use: ${remoteToDeleteFrom}`),
+      );
+    } else if (shouldPushToRemote && !remoteToDeleteFrom) {
+      console.log(
+        chalk.dim(
+          "No remotes configured. Only local cleanup will be performed.",
+        ),
+      );
+    }
+
+    const answer = await promptUser(
+      chalk.bold("\nProceed with cleanup? (y/N): "),
+    );
+    if (answer.toLowerCase() !== "y" && answer.toLowerCase() !== "yes") {
+      return {
+        success: false,
+        error: "Cleanup cancelled by user",
+        localTagsDeleted: 0,
+        remoteTagsDeleted: 0,
+        localTagNames: [],
+        remoteTagNames: [],
+        remoteTagErrors: [],
+        availableRemotes,
+      };
+    }
+  }
+
+  const localTagNames: string[] = [];
+  const remoteTagNames: string[] = [];
+  const remoteTagErrors: Array<{ tag: string; error: string }> = [];
+
+  // Delete local tags
+  for (const tag of archiveTags) {
+    const deleted = await deleteLocalTag(tag);
+    if (deleted) {
+      localTagNames.push(tag);
+    }
+  }
+
+  // Delete from remote (if remote is specified and exists)
+  if (shouldPushToRemote && remoteToDeleteFrom) {
+    for (const tag of localTagNames) {
+      const result = await deleteRemoteTag(tag, remoteToDeleteFrom);
+      if (result.ok) {
+        remoteTagNames.push(tag);
+      } else {
+        // Continue with local cleanup even if remote fails
+        remoteTagErrors.push({ tag, error: result.error });
+      }
+    }
+  }
+
+  // Build instructions message
+  const instructionsArr: string[] = [];
+  if (localTagNames.length > 0) {
+    const word = localTagNames.length === 1 ? "tag" : "tags";
+    instructionsArr.push(
+      chalk.green(`Deleted ${localTagNames.length} local archive ${word}.`),
+    );
+  }
+  if (remoteTagNames.length > 0) {
+    const word = remoteTagNames.length === 1 ? "tag" : "tags";
+    instructionsArr.push(
+      chalk.green(`Deleted ${remoteTagNames.length} remote archive ${word}.`),
+    );
+  }
+  if (remoteTagErrors.length > 0) {
+    const word = remoteTagErrors.length === 1 ? "tag" : "tags";
+    instructionsArr.push(
+      chalk.yellow(
+        `Failed to delete ${remoteTagErrors.length} remote ${word} (local cleanup continued).`,
+      ),
+    );
+  }
+
+  return {
+    success: true,
+    instructions: instructionsArr.join("\n"),
+    localTagsDeleted: localTagNames.length,
+    remoteTagsDeleted: remoteTagNames.length,
+    localTagNames,
+    remoteTagNames,
+    remoteTagErrors,
+    availableRemotes,
+  };
+}

src/core/close.ts

@@ -1,6 +1,12 @@
 import * as readline from "node:readline";
+import chalk from "chalk"; // removed console usage
 import type { CloseSessionOptions, CloseSessionResult } from "../types";
-import { runCommand, getSessionPath, getWorktreesForSession } from "./utils";
+import {
+  getSessionPath,
+  getWorktreesForSession,
+  runCommand,
+  sanitizeName,
+} from "./utils";
 
 /**
  * Prompts the user for input on the terminal.
@@ -43,35 +49,58 @@ async function promptUser(question: string): Promise<string> {
  * }
  * ```
  */
-export async function closeMultiModel(options: CloseSessionOptions): Promise<CloseSessionResult> {
+export async function closeMultiModel(
+  options: CloseSessionOptions,
+): Promise<CloseSessionResult> {
   const worktreesRemoved: string[] = [];
+  const instructionsArr: string[] = [];
   const branchesDeleted: string[] = [];
   const tagsCreated: string[] = [];
-  const warnings: string[] = [];
 
+  const safeSessionName = sanitizeName(options.sessionName);
   try {
     // Check if session exists
-    const { ok: sessionExists } = await runCommand(["tmux", "has-session", "-t", options.sessionName]);
+    const { ok: sessionExists } = await runCommand([
+      "tmux",
+      "has-session",
+      "-t",
+      options.sessionName,
+    ]);
 
     // Kill tmux session if it exists
     if (sessionExists) {
       await runCommand(["tmux", "kill-session", "-t", options.sessionName]);
+      instructionsArr.push(
+        chalk.green(`Closed session '${options.sessionName}'`),
+      );
+    } else {
+      instructionsArr.push(
+        chalk.yellow(`Session '${options.sessionName}' does not exist`),
+      );
     }
 
     // Get list of worktrees for this session before killing tmux
-    const worktrees = await getWorktreesForSession(options.sessionName);
+    const worktrees = await getWorktreesForSession(safeSessionName);
 
     // If cleanup requested and not forced, ask for confirmation
     if (options.cleanupWorktrees && !options.force && worktrees.length > 0) {
-      console.log(`\nThe following worktrees and branches will be removed:`);
-      worktrees.forEach((wt) => console.log(`  - ${wt.path} (branch: ${wt.branch})`));
+      console.log(
+        chalk.red("The following worktrees and branches will be removed:"),
+      );
+      worktrees.forEach((wt) => {
+        const msg = `  - ${wt.path} (branch: ${wt.branch})`;
+        console.log(msg.trim());
+      });
 
-      const answer = await promptUser("\nDo you want to proceed? (y/N): ");
+      const answer = await promptUser(
+        chalk.bold("\nDo you want to proceed? (y/N): "),
+      );
       if (answer.toLowerCase() !== "y" && answer.toLowerCase() !== "yes") {
         return {
           success: false,
-          sessionName: options.sessionName,
+          sessionName: safeSessionName,
           error: "Cleanup cancelled by user",
+          instructions: instructionsArr.join("\n"),
         };
       }
     }
@@ -86,28 +115,38 @@ export async function closeMultiModel(options: CloseSessionOptions): Promise<Clo
           await runCommand(["git", "worktree", "remove", "-f", worktree.path]);
           worktreesRemoved.push(worktree.path);
 
-          // Create an archive tag before deleting the branch for safe recovery
-          const timestamp = new Date().toISOString().replace(/[:.]/g, "-");
-          const archiveTag = `archive/${worktree.branch}-${timestamp}`;
-          const tagResult = await runCommand(["git", "tag", archiveTag, worktree.branch]);
+          // Optionally create an archive tag before deleting the branch for safe recovery
+          if (options.createArchiveTags !== false) {
+            const timestamp = new Date().toISOString().replace(/[:.]/g, "-");
+            const archiveTag = `archive/${worktree.branch}-${timestamp}`;
+            const tagResult = await runCommand([
+              "git",
+              "tag",
+              archiveTag,
+              worktree.branch,
+            ]);
 
-          if (tagResult.ok) {
-            tagsCreated.push(archiveTag);
-          } else {
-            const warningMsg = `Failed to create tag ${archiveTag} for branch ${worktree.branch}.`;
-            warnings.push(warningMsg);
-            console.warn(`Warning: ${warningMsg}`);
+            if (tagResult.ok) {
+              tagsCreated.push(archiveTag);
+            } else {
+              const warningMsg = chalk.red(
+                `Warning: Failed to create tag ${archiveTag} for branch ${worktree.branch}.`,
+              );
+              instructionsArr.push(warningMsg);
+            }
           }
 
           await runCommand(["git", "branch", "-D", worktree.branch]);
           branchesDeleted.push(worktree.branch);
         } catch (err) {
-          console.warn(`Warning: Failed to cleanup worktree ${worktree.path}: ${err}`);
+          instructionsArr.push(
+            chalk.red(`Failed to cleanup worktree ${worktree.path}: ${err}`),
+          );
         }
       }
 
       // Also remove the base directory
-      const worktreeBase = getSessionPath(options.sessionName);
+      const worktreeBase = getSessionPath(safeSessionName);
       try {
         await runCommand(["rm", "-rf", worktreeBase]);
       } catch {
@@ -115,26 +154,38 @@ export async function closeMultiModel(options: CloseSessionOptions): Promise<Clo
       }
 
       cleanupPerformed = worktreesRemoved.length > 0;
+      if (cleanupPerformed) {
+        instructionsArr.push(
+          chalk.dim(
+            `Removed ${worktreesRemoved.length} worktrees, alongwith their branches.`,
+          ),
+        );
+        if (tagsCreated.length > 0) {
+          instructionsArr.push(
+            chalk.dim(`Created archive tags: ${tagsCreated.join(", ")}.`),
+          );
+        }
+      }
     }
 
     return {
       success: true,
-      sessionName: options.sessionName,
+      sessionName: safeSessionName,
       cleanupPerformed,
       worktreesRemoved,
       branchesDeleted,
       tagsCreated,
-      warnings,
+      instructions: instructionsArr.join("\n"),
     };
   } catch (error) {
     return {
       success: false,
-      sessionName: options.sessionName,
+      sessionName: safeSessionName,
       error: String(error),
       worktreesRemoved,
       branchesDeleted,
       tagsCreated,
-      warnings,
+      instructions: instructionsArr.join("\n"),
     };
   }
 }

src/core/index.ts

@@ -1,3 +1,4 @@
-export { launchMultiModel } from "./launch";
+export { cleanupMultiModel } from "./cleanup";
 export { closeMultiModel } from "./close";
+export { openMultiModel } from "./open";
 export * from "./utils";

src/core/open.ts

@@ -1,16 +1,16 @@
 import * as fs from "node:fs";
+import chalk from "chalk";
 import type { MultiModelOptions, MultiModelResult } from "../types";
 import {
-  runCommand,
-  normalizeModels,
-  findDuplicates,
   createWindowPlans,
+  findDuplicates,
   formatInvalidModelError,
-  sanitizeName,
   getWorktreePath,
-  getSessionPath,
-  undoWorktree,
   launchModelInWindow,
+  normalizeModels,
+  runCommand,
+  sanitizeName,
+  undoWorktree,
 } from "./utils";
 
 /**
@@ -24,7 +24,7 @@ import {
  *
  * @example
  * ```ts
- * const result = await launchMultiModel({
+ * const result = await openMultiModel({
  *   sessionName: "compare",
  *   models: ["openai/gpt-5.2", "anthropic/claude-3-5-sonnet"],
  *   binaryName: "opencode",
@@ -34,7 +34,9 @@ import {
  * }
  * ```
  */
-export async function launchMultiModel(options: MultiModelOptions): Promise<MultiModelResult> {
+export async function openMultiModel(
+  options: MultiModelOptions,
+): Promise<MultiModelResult> {
   const sessionName = options.sessionName.trim();
   const safeSessionName = sanitizeName(sessionName);
   const models = normalizeModels(options.models);
@@ -42,11 +44,19 @@ export async function launchMultiModel(options: MultiModelOptions): Promise<Mult
   const mode = options.mode || "cli";
 
   if (!sessionName) {
-    return { success: false, sessionName: "", error: "Error: `sessionName` must not be empty." };
+    return {
+      success: false,
+      sessionName: "",
+      error: "Error: `sessionName` must not be empty.",
+    };
   }
 
   if (models.length === 0) {
-    return { success: false, sessionName, error: "Error: Model names must not be empty." };
+    return {
+      success: false,
+      sessionName,
+      error: "Error: Model names must not be empty.",
+    };
   }
 
   const duplicateModels = findDuplicates(models);
@@ -58,19 +68,35 @@ export async function launchMultiModel(options: MultiModelOptions): Promise<Mult
     };
   }
 
-  const gitRepoCheck = await runCommand(["git", "rev-parse", "--is-inside-work-tree"]);
+  const gitRepoCheck = await runCommand([
+    "git",
+    "rev-parse",
+    "--is-inside-work-tree",
+  ]);
   if (!gitRepoCheck.ok) {
-    return { success: false, sessionName, error: "Error: `multi-model` requires a git repository." };
+    return {
+      success: false,
+      sessionName,
+      error: "Error: `multi-model` requires a git repository.",
+    };
   }
 
   const tmuxExists = await runCommand(["command", "-v", "tmux"]);
   if (!tmuxExists.ok) {
-    return { success: false, sessionName, error: "Error: `tmux` is not installed or not on `PATH`." };
+    return {
+      success: false,
+      sessionName,
+      error: "Error: `tmux` is not installed or not on `PATH`.",
+    };
   }
 
   const binaryExists = await runCommand(["command", "-v", binaryName]);
   if (!binaryExists.ok) {
-    return { success: false, sessionName, error: `Error: \`${binaryName}\` is not installed or not on \`PATH\`.` };
+    return {
+      success: false,
+      sessionName,
+      error: `Error: \`${binaryName}\` is not installed or not on \`PATH\`.`,
+    };
   }
 
   const modelListResult = await runCommand([binaryName, "models"]);
@@ -89,12 +115,25 @@ export async function launchMultiModel(options: MultiModelOptions): Promise<Mult
 
   const invalidModels = models.filter((model) => !allowlist.includes(model));
   if (invalidModels.length > 0) {
-    return { success: false, sessionName, error: formatInvalidModelError(invalidModels, allowlist) };
+    return {
+      success: false,
+      sessionName,
+      error: formatInvalidModelError(invalidModels, allowlist),
+    };
   }
 
-  const sessionExists = await runCommand(["tmux", "has-session", "-t", sessionName]);
+  const sessionExists = await runCommand([
+    "tmux",
+    "has-session",
+    "-t",
+    sessionName,
+  ]);
   if (sessionExists.ok) {
-    return { success: false, sessionName, error: "Error: Session already exists. Use a different `sessionName`." };
+    return {
+      success: false,
+      sessionName,
+      error: "Error: Session already exists. Use a different `sessionName`.",
+    };
   }
 
   const windowPlans = createWindowPlans(models);
@@ -110,30 +149,61 @@ export async function launchMultiModel(options: MultiModelOptions): Promise<Mult
 
     if (fs.existsSync(worktreePath)) {
       if (!isFirst) {
-        failedModels.push(`${plan.model} (Worktree path already exists at ${worktreePath})`);
+        failedModels.push(
+          `${plan.model} (Worktree path already exists at ${worktreePath})`,
+        );
         continue;
       } else {
-        return { success: false, sessionName, error: `Error: Worktree path already exists at ${worktreePath}. Clean it up first.` };
+        return {
+          success: false,
+          sessionName,
+          error: `Error: Worktree path already exists at ${worktreePath}. Clean it up first.`,
+        };
       }
     }
 
-    const branchExists = await runCommand(["git", "show-ref", "--verify", "--quiet", `refs/heads/${branchName}`]);
+    const branchExists = await runCommand([
+      "git",
+      "show-ref",
+      "--verify",
+      "--quiet",
+      `refs/heads/${branchName}`,
+    ]);
     if (branchExists.ok) {
       if (!isFirst) {
-        failedModels.push(`${plan.model} (Branch '${branchName}' already exists)`);
+        failedModels.push(
+          `${plan.model} (Branch '${branchName}' already exists)`,
+        );
         continue;
       } else {
-        return { success: false, sessionName, error: `Error: Branch '${branchName}' already exists.` };
+        return {
+          success: false,
+          sessionName,
+          error: `Error: Branch '${branchName}' already exists.`,
+        };
       }
     }
 
-    const worktreeResult = await runCommand(["git", "worktree", "add", "-b", branchName, worktreePath]);
+    const worktreeResult = await runCommand([
+      "git",
+      "worktree",
+      "add",
+      "-b",
+      branchName,
+      worktreePath,
+    ]);
     if (!worktreeResult.ok) {
       if (!isFirst) {
-        failedModels.push(`${plan.model} (Failed to create worktree: ${worktreeResult.stderr})`);
+        failedModels.push(
+          `${plan.model} (Failed to create worktree: ${worktreeResult.stderr})`,
+        );
         continue;
       } else {
-        return { success: false, sessionName, error: `Error: Failed to create worktree for ${plan.model}: ${worktreeResult.stderr}` };
+        return {
+          success: false,
+          sessionName,
+          error: `Error: Failed to create worktree for ${plan.model}: ${worktreeResult.stderr}`,
+        };
       }
     }
 
@@ -153,7 +223,9 @@ export async function launchMultiModel(options: MultiModelOptions): Promise<Mult
       if (!sessionCreateResult.ok) {
         const undoErrors = await undoWorktree(worktreePath, branchName);
         let errorMsg = `Error: Failed to create tmux session '${sessionName}'.${sessionCreateResult.stderr ? ` ${sessionCreateResult.stderr}` : ""}`;
-        if (undoErrors.length > 0) errorMsg += ` Cleanup errors: ${undoErrors.join(", ")}`;
+        if (undoErrors.length > 0) {
+          errorMsg += ` Cleanup errors: ${undoErrors.join(", ")}`;
+        }
         return { success: false, sessionName, error: errorMsg };
       }
     } else {
@@ -170,20 +242,35 @@ export async function launchMultiModel(options: MultiModelOptions): Promise<Mult
       ]);
 
       if (!windowCreateResult.ok) {
-        failedModels.push(`${plan.model} (${windowCreateResult.stderr || "failed to create window"})`);
+        failedModels.push(
+          `${plan.model} (${windowCreateResult.stderr || "failed to create window"})`,
+        );
         const undoErrors = await undoWorktree(worktreePath, branchName);
-        if (undoErrors.length > 0) failedModels.push(`cleanup failed for ${plan.model}: ${undoErrors.join(", ")}`);
+        if (undoErrors.length > 0) {
+          failedModels.push(
+            `cleanup failed for ${plan.model}: ${undoErrors.join(", ")}`,
+          );
+        }
         continue;
       }
     }
 
-    const launchResult = await launchModelInWindow(sessionName, plan, binaryName);
+    const launchResult = await launchModelInWindow(
+      sessionName,
+      plan,
+      binaryName,
+    );
     if (launchResult.ok) {
       succeededModels.push(plan.model);
     } else {
-      failedModels.push(`${plan.model} (${launchResult.stderr || "failed to send launch command"})`);
+      failedModels.push(
+        `${plan.model} (${launchResult.stderr || "failed to send launch command"})`,
+      );
       const undoErrors = await undoWorktree(worktreePath, branchName);
-      if (undoErrors.length > 0) failedModels.push(`cleanup failed for ${plan.model}: ${undoErrors.join(", ")}`);
+      if (undoErrors.length > 0)
+        failedModels.push(
+          `cleanup failed for ${plan.model}: ${undoErrors.join(", ")}`,
+        );
     }
   }
 
@@ -201,13 +288,21 @@ export async function launchMultiModel(options: MultiModelOptions): Promise<Mult
       sessionName,
       windows: windowNames,
       instructions: [
-        `Error: Created tmux session '${sessionName}', but some model launches failed.`,
-        `Succeeded: ${succeededModels.length > 0 ? succeededModels.join(", ") : "none"}.`,
-        `Failed: ${failedModels.join(", ")}.`,
-        `Attach with \`${attachCommand}\` to inspect the session.`,
-        `Cleanup when done using either:`,
-        `1. ${primaryCleanup}`,
-        `2. Or run manually: \`${cleanupCommand}\``,
+        chalk.red(
+          `Error: Created tmux session '${sessionName}', but some model launches failed.`,
+        ),
+        chalk.red(`Failed: ${failedModels.join(", ")}.`),
+        chalk.dim(
+          `Succeeded: ${succeededModels.length > 0 ? succeededModels.join(", ") : "none"}.`,
+        ),
+        "",
+        chalk.bold(`Attach with \`${attachCommand}\` to inspect the session.`),
+        "",
+        chalk.dim(`When finished, clean up using:`),
+        primaryCleanup,
+        "",
+        chalk.dim(`Alternate manual cleanup - `),
+        chalk.dim(cleanupCommand),
       ].join("\n"),
     };
   }
@@ -217,10 +312,13 @@ export async function launchMultiModel(options: MultiModelOptions): Promise<Mult
     sessionName,
     windows: windowNames,
     instructions: [
-      `Use \`${attachCommand}\` to join session.`,
-      `When finished, clean up using either:`,
-      `1. ${primaryCleanup}`,
-      `2. Or run manually: \`${cleanupCommand}\``,
+      chalk.bold(`Use \`${attachCommand}\` to join session.`),
+      "",
+      chalk.dim(`When finished, clean up using:`),
+      primaryCleanup,
+      "",
+      chalk.dim(`Alternate manual cleanup - `),
+      chalk.dim(cleanupCommand),
     ].join("\n"),
   };
 }

src/core/utils.ts

@@ -136,7 +136,10 @@ export function createWindowPlans(models: string[]): WindowLaunchPlan[] {
     }
 
     const suffix = `-${nextCount}`;
-    const trimmedBase = baseName.slice(0, Math.max(1, WINDOW_NAME_LIMIT - suffix.length));
+    const trimmedBase = baseName.slice(
+      0,
+      Math.max(1, WINDOW_NAME_LIMIT - suffix.length),
+    );
 
     return {
       model,
@@ -194,7 +197,10 @@ export function levenshtein(left: string, right: string): number {
  * // ["openai/gpt-5.4", "openai/gpt-5.4-pro"]
  * ```
  */
-export function suggestModels(requested: string, allowlist: string[]): string[] {
+export function suggestModels(
+  requested: string,
+  allowlist: string[],
+): string[] {
   const normalizedRequested = requested.toLowerCase();
 
   return allowlist
@@ -212,7 +218,11 @@ export function suggestModels(requested: string, allowlist: string[]): string[]
         score: distance + containsBoost,
       };
     })
-    .sort((left, right) => left.score - right.score || left.candidate.localeCompare(right.candidate))
+    .sort(
+      (left, right) =>
+        left.score - right.score ||
+        left.candidate.localeCompare(right.candidate),
+    )
     .slice(0, MAX_SUGGESTIONS)
     .map(({ candidate }) => candidate);
 }
@@ -229,7 +239,10 @@ export function suggestModels(requested: string, allowlist: string[]): string[]
  * const message = formatInvalidModelError(["openai/gpt5.4"], ["openai/gpt-5.4"]);
  * ```
  */
-export function formatInvalidModelError(invalidModels: string[], allowlist: string[]): string {
+export function formatInvalidModelError(
+  invalidModels: string[],
+  allowlist: string[],
+): string {
   const firstInvalidModel = invalidModels[0]!;
   const suggestions = suggestModels(firstInvalidModel, allowlist);
   const suggestionText =
@@ -264,7 +277,14 @@ export async function launchModelInWindow(
 ): Promise<CommandResult> {
   const launchCommand = `${binaryName} --model ${shellQuote(plan.model)}`;
 
-  return runCommand(["tmux", "send-keys", "-t", `${sessionName}:${plan.windowName}`, launchCommand, "C-m"]);
+  return runCommand([
+    "tmux",
+    "send-keys",
+    "-t",
+    `${sessionName}:${plan.windowName}`,
+    launchCommand,
+    "C-m",
+  ]);
 }
 
 /**
@@ -280,7 +300,10 @@ export async function launchModelInWindow(
  * ```
  */
 export function sanitizeName(name: string): string {
-  return name.replace(/[^a-zA-Z0-9_-]/g, "-").replace(/-+/g, "-").replace(/^-|-$/g, "");
+  return name
+    .replace(/[^a-zA-Z0-9_-]/g, "-")
+    .replace(/-+/g, "-")
+    .replace(/^-|-$/g, "");
 }
 
 /**
@@ -297,7 +320,14 @@ export function sanitizeName(name: string): string {
  */
 export function getSessionPath(sessionName: string): string {
   const homedir = os.homedir();
-  return path.join(homedir, ".local", "share", "opencode", "multi-model", sessionName);
+  return path.join(
+    homedir,
+    ".local",
+    "share",
+    "opencode",
+    "multi-model",
+    sessionName,
+  );
 }
 
 /**
@@ -313,7 +343,10 @@ export function getSessionPath(sessionName: string): string {
  * // "/home/user/.local/share/opencode/multi-model/my-session/gpt-5-2"
  * ```
  */
-export function getWorktreePath(safeSession: string, windowName: string): string {
+export function getWorktreePath(
+  safeSession: string,
+  windowName: string,
+): string {
   return path.join(getSessionPath(safeSession), windowName);
 }
 
@@ -328,11 +361,18 @@ export function getWorktreePath(safeSession: string, windowName: string): string
  * const worktrees = await getWorktreesForSession("my-session");
  * ```
  */
-export async function getWorktreesForSession(sessionName: string): Promise<WorktreeInfo[]> {
-  const { stdout } = await runCommand(["git", "worktree", "list", "--porcelain"]);
+export async function getWorktreesForSession(
+  sessionName: string,
+): Promise<WorktreeInfo[]> {
+  const { stdout } = await runCommand([
+    "git",
+    "worktree",
+    "list",
+    "--porcelain",
+  ]);
   const worktrees: WorktreeInfo[] = [];
 
-  const sessionPath = getSessionPath(sessionName);
+  const sessionPath = getSessionPath(sanitizeName(sessionName));
 
   let currentWorktree: Partial<WorktreeInfo> = {};
 
@@ -371,13 +411,26 @@ export async function getWorktreesForSession(sessionName: string): Promise<Workt
  * if (errors.length > 0) console.error(errors);
  * ```
  */
-export async function undoWorktree(worktreePath: string, branchName: string): Promise<string[]> {
+export async function undoWorktree(
+  worktreePath: string,
+  branchName: string,
+): Promise<string[]> {
   const errors: string[] = [];
-  const removeRes = await runCommand(["git", "worktree", "remove", "-f", worktreePath]);
-  if (!removeRes.ok) errors.push(`Failed to remove worktree ${worktreePath}: ${removeRes.stderr}`);
+  const removeRes = await runCommand([
+    "git",
+    "worktree",
+    "remove",
+    "-f",
+    worktreePath,
+  ]);
+  if (!removeRes.ok)
+    errors.push(
+      `Failed to remove worktree ${worktreePath}: ${removeRes.stderr}`,
+    );
 
   const branchRes = await runCommand(["git", "branch", "-D", branchName]);
-  if (!branchRes.ok) errors.push(`Failed to delete branch ${branchName}: ${branchRes.stderr}`);
+  if (!branchRes.ok)
+    errors.push(`Failed to delete branch ${branchName}: ${branchRes.stderr}`);
   return errors;
 }
 

src/index.ts

@@ -1,13 +1,15 @@
 import type { Plugin } from "@opencode-ai/plugin";
-import { openTool } from "./tools/open";
+import { cleanupTool } from "./tools/cleanup";
 import { closeTool } from "./tools/close";
+import { openTool } from "./tools/open";
 
 /**
  * OpenCode plugin that provides multi-model tmux session management tools.
  *
- * Registers two tools:
+ * Registers three tools:
  * - `multi-model-open`: Launch multiple AI models in a tmux session
  * - `multi-model-close`: Close a multi-model session and cleanup resources
+ * - `multi-model-cleanup`: Delete all archive tags from local and remote repositories
  *
  * @example
  * ```json
@@ -22,11 +24,12 @@ const OpenCodeMultiModelPlugin: Plugin = async (_ctx) => {
     tool: {
       "multi-model-open": openTool,
       "multi-model-close": closeTool,
+      "multi-model-cleanup": cleanupTool,
     },
   };
 };
 
 export default OpenCodeMultiModelPlugin;
-export { openTool, closeTool };
 export * from "./core/index";
 export * from "./types";
+export { cleanupTool, closeTool, openTool };

src/tools/cleanup.ts

@@ -0,0 +1,45 @@
+import { tool } from "@opencode-ai/plugin";
+import { cleanupMultiModel } from "../core/cleanup";
+
+/**
+ * OpenCode tool definition for cleaning up archive tags.
+ *
+ * Deletes archive tags (format: archive/*) from local and remote repositories.
+ * Used to clean up recovery tags created by the close command.
+ */
+export const cleanupTool = tool({
+  description:
+    "Delete all archive tags from local and optionally remote repository",
+  args: {
+    remote: tool.schema
+      .union([
+        tool.schema
+          .string()
+          .describe(
+            "Remote name to push deletions to. Error if doesn't exist.",
+          ),
+        tool.schema
+          .literal(false)
+          .describe("Only delete local tags, don't push to remote."),
+      ])
+      .optional()
+      .describe(
+        "Remote handling: string=specific remote, false=local-only, undefined=first available remote",
+      ),
+  },
+  async execute(args, _context) {
+    // In plugin mode, we skip confirmation (force=true)
+    const result = await cleanupMultiModel({
+      force: true,
+      remote: args.remote,
+    });
+
+    if (!result.success) {
+      return result.error!;
+    }
+
+    return (
+      result.instructions ?? `Deleted ${result.localTagsDeleted} local tags.`
+    );
+  },
+});

src/tools/close.ts

@@ -8,16 +8,32 @@ import { closeMultiModel } from "../core/close";
  * creates archive tags, and deletes associated branches.
  */
 export const closeTool = tool({
-  description: "Close a multi-model tmux session and optionally cleanup worktrees and branches",
+  description:
+    "Close a multi-model tmux session and optionally cleanup worktrees and branches",
   args: {
-    sessionName: tool.schema.string().min(1).describe("tmux session name to close"),
-    cleanupWorktrees: tool.schema.boolean().default(true).describe("whether to remove worktrees and delete branches (default: true)"),
+    sessionName: tool.schema
+      .string()
+      .min(1)
+      .describe("tmux session name to close"),
+    cleanupWorktrees: tool.schema
+      .boolean()
+      .default(true)
+      .describe(
+        "whether to remove worktrees and delete branches (default: true)",
+      ),
+    createArchiveTags: tool.schema
+      .boolean()
+      .default(true)
+      .describe(
+        "whether to create archive tags before deleting branches (default: true)",
+      ),
   },
-  async execute(args, context) {
+  async execute(args, _context) {
     // In plugin mode, we skip confirmation (force=true) since there's no interactive terminal
     const result = await closeMultiModel({
       sessionName: args.sessionName,
       cleanupWorktrees: args.cleanupWorktrees,
+      createArchiveTags: args.createArchiveTags,
       force: true,
     });
 
@@ -25,17 +41,6 @@ export const closeTool = tool({
       return result.error!;
     }
 
-    let details = "";
-    if (result.cleanupPerformed) {
-      details += ` Removed ${result.worktreesRemoved?.length || 0} worktrees.`;
-      if (result.tagsCreated && result.tagsCreated.length > 0) {
-        details += ` Created backup tags: ${result.tagsCreated.join(", ")}.`;
-      }
-      if (result.warnings && result.warnings.length > 0) {
-        details += ` Warnings: ${result.warnings.join("; ")}.`;
-      }
-    }
-
-    return `Session "${result.sessionName}" has been closed.${details}`;
+    return result.instructions;
   },
 });

src/tools/open.ts

@@ -1,5 +1,5 @@
 import { tool } from "@opencode-ai/plugin";
-import { launchMultiModel } from "../core/launch";
+import { openMultiModel } from "../core/open";
 import { getBinaryName } from "../core/utils";
 
 /**
@@ -11,7 +11,10 @@ import { getBinaryName } from "../core/utils";
 export const openTool = tool({
   description: "Launch multiple OpenCode models in tmux",
   args: {
-    sessionName: tool.schema.string().min(1).describe("tmux session name to create"),
+    sessionName: tool.schema
+      .string()
+      .min(1)
+      .describe("tmux session name to create"),
     models: tool.schema
       .array(tool.schema.string().min(1))
       .min(1)
@@ -20,7 +23,7 @@ export const openTool = tool({
   async execute(args, context) {
     const binaryName = getBinaryName();
 
-    const result = await launchMultiModel({
+    const result = await openMultiModel({
       sessionName: args.sessionName,
       models: args.models,
       binaryName,
@@ -39,6 +42,9 @@ export const openTool = tool({
       return result.error!;
     }
 
-    return result.instructions || `Created session "${result.sessionName}" with ${result.windows?.length || 0} windows`;
+    return (
+      result.instructions ||
+      `Created session "${result.sessionName}" with ${result.windows?.length || 0} windows`
+    );
   },
 });

src/types.ts

@@ -32,6 +32,8 @@ export interface MultiModelResult {
  * Options for closing a multi-model tmux session.
  */
 export interface CloseSessionOptions {
+  /** Whether to create archive tags before deleting branches. */
+  createArchiveTags?: boolean;
   /** Name of the tmux session to close. */
   sessionName: string;
   /** Whether to remove worktrees and delete branches. */
@@ -44,6 +46,8 @@ export interface CloseSessionOptions {
  * Result returned after attempting to close a multi-model session.
  */
 export interface CloseSessionResult {
+  /** Console messages and instructions. */
+  instructions: string;
   /** Whether the close succeeded. */
   success: boolean;
   /** The session name that was closed. */
@@ -58,8 +62,6 @@ export interface CloseSessionResult {
   branchesDeleted?: string[];
   /** Archive tags that were created before branch deletion. */
   tagsCreated?: string[];
-  /** Warning messages. */
-  warnings?: string[];
 }
 
 /**
@@ -72,6 +74,45 @@ export interface WindowLaunchPlan {
   windowName: string;
 }
 
+/**
+ * Options for cleaning up archive tags.
+ */
+export interface CleanupOptions {
+  /** Skip confirmation prompts. */
+  force?: boolean;
+  /**
+   * Remote name to push deletions to.
+   * - If string: use specified remote (error if doesn't exist)
+   * - If undefined: use first available remote from git remote -v
+   * - If false: only local cleanup (--no-remote flag)
+   */
+  remote?: string | false;
+}
+
+/**
+ * Result returned after attempting to cleanup archive tags.
+ */
+export interface CleanupResult {
+  /** Whether the cleanup succeeded. */
+  success: boolean;
+  /** Error message if the cleanup failed. */
+  error?: string;
+  /** Summary message for the user. */
+  instructions?: string;
+  /** Number of local tags deleted. */
+  localTagsDeleted: number;
+  /** Number of remote tags deleted. */
+  remoteTagsDeleted: number;
+  /** Names of tags that were deleted locally. */
+  localTagNames: string[];
+  /** Names of tags deleted from remote. */
+  remoteTagNames: string[];
+  /** Tags that failed remote deletion. */
+  remoteTagErrors: Array<{ tag: string; error: string }>;
+  /** Available remotes discovered. */
+  availableRemotes: string[];
+}
+
 /**
  * Result of running a shell command.
  */

tests/cleanup.test.ts

@@ -0,0 +1,406 @@
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  mock,
+  spyOn,
+  test,
+} from "bun:test";
+import * as readline from "node:readline";
+import { cleanupMultiModel } from "../src/core/cleanup";
+
+const originalBun$: typeof Bun.$ = (globalThis as any).Bun?.$;
+let mockCommandResponses: Record<
+  string,
+  { ok: boolean; stdout: string; stderr: string }
+> = {};
+let executedCommands: string[] = [];
+
+function setupMockBun$() {
+  const mockFn = mock((_strings: TemplateStringsArray, ...values: any[]) => {
+    const parts = values[0] as string[];
+    const commandSignature = parts.join(" ");
+    executedCommands.push(commandSignature);
+    const response = mockCommandResponses[commandSignature] ?? {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    return {
+      quiet: () => ({
+        nothrow: async () => ({
+          exitCode: response.ok ? 0 : 1,
+          stdout: { toString: () => response.stdout },
+          stderr: { toString: () => response.stderr },
+        }),
+      }),
+    };
+  });
+  (globalThis as any).Bun.$ = mockFn;
+  return mockFn;
+}
+
+function restoreOriginalBun$() {
+  (globalThis as any).Bun.$ = originalBun$;
+}
+
+describe("cleanupMultiModel", () => {
+  let _bunMock: ReturnType<typeof setupMockBun$>;
+
+  beforeEach(() => {
+    _bunMock = setupMockBun$();
+    executedCommands = [];
+    mockCommandResponses = {};
+  });
+
+  afterEach(() => {
+    restoreOriginalBun$();
+  });
+
+  test("no archive tags found - returns success with message", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "origin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({ force: true });
+
+    expect(result.success).toBe(true);
+    expect(result.localTagsDeleted).toBe(0);
+    expect(result.remoteTagsDeleted).toBe(0);
+    expect(result.instructions).toContain("No archive tags found");
+  });
+
+  test("user cancels confirmation - returns success=false", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "origin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1\narchive/test-2",
+      stderr: "",
+    };
+
+    const mockInterface = {
+      question: (_q: string, cb: (a: string) => void) => cb("n"),
+      close: () => {},
+    } as any;
+    spyOn(readline, "createInterface").mockImplementation(() => mockInterface);
+
+    const result = await cleanupMultiModel({ force: false });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toBe("Cleanup cancelled by user");
+    expect(result.localTagsDeleted).toBe(0);
+    expect(result.remoteTagsDeleted).toBe(0);
+  });
+
+  test("force mode skips confirmation", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "origin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git push origin --delete archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({ force: true });
+
+    expect(result.success).toBe(true);
+    expect(result.localTagsDeleted).toBe(1);
+    expect(executedCommands).toContain("git tag -d archive/test-1");
+  });
+
+  test("--no-remote flag (remote=false) - only local cleanup, no remote push", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "origin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({ force: true, remote: false });
+
+    expect(result.success).toBe(true);
+    expect(result.localTagsDeleted).toBe(1);
+    expect(result.remoteTagsDeleted).toBe(0);
+    expect(executedCommands).toContain("git tag -d archive/test-1");
+    expect(executedCommands.some((c) => c.startsWith("git push"))).toBe(false);
+  });
+
+  test("remote deletion failure continues local cleanup", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "origin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1\narchive/test-2",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-2"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git push origin --delete archive/test-1"] = {
+      ok: false,
+      stdout: "",
+      stderr: "remote error",
+    };
+    mockCommandResponses["git push origin --delete archive/test-2"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({ force: true });
+
+    expect(result.success).toBe(true);
+    expect(result.localTagsDeleted).toBe(2);
+    expect(result.remoteTagsDeleted).toBe(1);
+    expect(result.remoteTagErrors.length).toBe(1);
+    expect(result.remoteTagErrors[0]?.tag).toBe("archive/test-1");
+  });
+
+  test("dynamic remote detection - remote=undefined uses first available remote", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "upstream\norigin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git push upstream --delete archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({ force: true, remote: undefined });
+
+    expect(result.success).toBe(true);
+    expect(executedCommands).toContain(
+      "git push upstream --delete archive/test-1",
+    );
+  });
+
+  test("remote name validation - uses specified remote if it exists", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "upstream\norigin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git push upstream --delete archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({
+      force: true,
+      remote: "upstream",
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.availableRemotes).toEqual(["upstream", "origin"]);
+    expect(executedCommands).toContain(
+      "git push upstream --delete archive/test-1",
+    );
+  });
+
+  test("remote error - returns error if specified remote doesn't exist", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "origin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({
+      force: true,
+      remote: "nonexistent",
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Remote 'nonexistent' not found");
+    expect(result.error).toContain("Available remotes: origin");
+  });
+
+  test("no remotes configured - only local cleanup", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({ force: true });
+
+    expect(result.success).toBe(true);
+    expect(result.availableRemotes).toEqual([]);
+    expect(result.remoteTagsDeleted).toBe(0);
+    expect(executedCommands.some((c) => c.startsWith("git push"))).toBe(false);
+  });
+
+  test("user confirms cleanup when not forced - proceeds with deletion", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "origin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git push origin --delete archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const mockInterface = {
+      question: (_q: string, cb: (a: string) => void) => cb("y"),
+      close: () => {},
+    } as any;
+    spyOn(readline, "createInterface").mockImplementation(() => mockInterface);
+
+    const result = await cleanupMultiModel({ force: false });
+
+    expect(result.success).toBe(true);
+    expect(result.localTagsDeleted).toBe(1);
+    expect(result.remoteTagsDeleted).toBe(1);
+    expect(executedCommands).toContain("git tag -d archive/test-1");
+    expect(executedCommands).toContain(
+      "git push origin --delete archive/test-1",
+    );
+  });
+
+  test("multiple archive tags deleted", async () => {
+    mockCommandResponses["git remote"] = {
+      ok: true,
+      stdout: "origin",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -l archive/*"] = {
+      ok: true,
+      stdout: "archive/test-1\narchive/test-2\narchive/test-3",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-2"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git tag -d archive/test-3"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git push origin --delete archive/test-1"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git push origin --delete archive/test-2"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git push origin --delete archive/test-3"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await cleanupMultiModel({ force: true });
+
+    expect(result.success).toBe(true);
+    expect(result.localTagsDeleted).toBe(3);
+    expect(result.remoteTagsDeleted).toBe(3);
+    expect(result.localTagNames).toEqual([
+      "archive/test-1",
+      "archive/test-2",
+      "archive/test-3",
+    ]);
+  });
+});

tests/close.test.ts

@@ -0,0 +1,484 @@
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  mock,
+  spyOn,
+  test,
+} from "bun:test";
+import * as os from "node:os";
+import * as readline from "node:readline";
+import { closeMultiModel } from "../src/core/close";
+
+const originalBun$: typeof Bun.$ = (globalThis as any).Bun?.$;
+let mockCommandResponses: Record<
+  string,
+  { ok: boolean; stdout: string; stderr: string }
+> = {};
+let executedCommands: string[] = [];
+
+function setupMockBun$() {
+  const mockFn = mock((_strings: TemplateStringsArray, ...values: any[]) => {
+    const parts = values[0] as string[];
+    const commandSignature = parts.join(" ");
+    executedCommands.push(commandSignature);
+    const response = mockCommandResponses[commandSignature] ?? {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    return {
+      quiet: () => ({
+        nothrow: async () => ({
+          exitCode: response.ok ? 0 : 1,
+          stdout: { toString: () => response.stdout },
+          stderr: { toString: () => response.stderr },
+        }),
+      }),
+    };
+  });
+  (globalThis as any).Bun.$ = mockFn;
+  return mockFn;
+}
+
+function restoreOriginalBun$() {
+  (globalThis as any).Bun.$ = originalBun$;
+}
+
+describe("closeMultiModel", () => {
+  let _bunMock: ReturnType<typeof setupMockBun$>;
+
+  beforeEach(() => {
+    spyOn(os, "homedir").mockReturnValue("/home/user");
+    _bunMock = setupMockBun$();
+    executedCommands = [];
+    mockCommandResponses = {};
+  });
+
+  afterEach(() => {
+    restoreOriginalBun$();
+  });
+
+  test("kills existing session without cleanup", async () => {
+    mockCommandResponses["tmux has-session -t test-session"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["tmux kill-session -t test-session"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    // No worktrees
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await closeMultiModel({
+      sessionName: "test-session",
+      cleanupWorktrees: false,
+      force: false,
+    });
+    expect(result.success).toBe(true);
+    expect(result.cleanupPerformed).toBe(false);
+    expect(result.worktreesRemoved).toEqual([]);
+    expect(executedCommands).toContain("tmux has-session -t test-session");
+    expect(executedCommands).toContain("tmux kill-session -t test-session");
+  });
+
+  test("no session exists, no cleanup", async () => {
+    mockCommandResponses["tmux has-session -t test-session"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await closeMultiModel({
+      sessionName: "test-session",
+      cleanupWorktrees: false,
+      force: false,
+    });
+    expect(result.success).toBe(true);
+    expect(result.cleanupPerformed).toBe(false);
+    expect(result.worktreesRemoved).toEqual([]);
+    expect(executedCommands).toContain("tmux has-session -t test-session");
+    // No kill-session should be issued
+    expect(
+      executedCommands.some((c) => c.startsWith("tmux kill-session")),
+    ).toBe(false);
+  });
+
+  test("cleanup works with worktrees and force, all succeeds", async () => {
+    mockCommandResponses["tmux has-session -t test-session"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    const worktreePath =
+      "/home/user/.local/share/opencode/multi-model/test-session/model";
+    const worktreeListOutput = `worktree ${worktreePath}\nbranch refs/heads/opencode/test-session/model`;
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: worktreeListOutput,
+      stderr: "",
+    };
+    mockCommandResponses[`git worktree remove -f ${worktreePath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git branch -D opencode/test-session/model"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    // Tag command will default to ok:true via fallback
+    mockCommandResponses[
+      "rm -rf /home/user/.local/share/opencode/multi-model/test-session"
+    ] = { ok: true, stdout: "", stderr: "" };
+
+    // Freeze timestamp for deterministic tag name
+    const fixedDate = new Date("2023-01-01T00:00:00.000Z");
+    const OriginalDate = Date;
+    global.Date = class extends OriginalDate {
+      constructor() {
+        super();
+        // biome-ignore lint/correctness/noConstructorReturn: time-mocking required
+        return fixedDate;
+      }
+      override toISOString() {
+        return "2023-01-01T00:00:00.000Z";
+      }
+    } as any;
+
+    const result = await closeMultiModel({
+      sessionName: "test-session",
+      cleanupWorktrees: true,
+      force: true,
+    });
+    // Restore Date
+    global.Date = OriginalDate;
+
+    expect(result.success).toBe(true);
+    expect(result.cleanupPerformed).toBe(true);
+    expect(result.worktreesRemoved).toEqual([worktreePath]);
+    expect(result.branchesDeleted).toEqual(["opencode/test-session/model"]);
+    expect(result.tagsCreated?.length).toBe(1);
+
+    // Ensure removal commands were executed
+    expect(executedCommands).toContain(
+      `git worktree remove -f ${worktreePath}`,
+    );
+    expect(executedCommands).toContain(
+      `git branch -D opencode/test-session/model`,
+    );
+  });
+
+  test("user cancels cleanup when not forced", async () => {
+    mockCommandResponses["tmux has-session -t test-session"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    const worktreePath =
+      "/home/user/.local/share/opencode/multi-model/test-session/model";
+    const worktreeListOutput = `worktree ${worktreePath}\nbranch refs/heads/opencode/test-session/model`;
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: worktreeListOutput,
+      stderr: "",
+    };
+
+    // Stub readline to return "n"
+    const mockInterface = {
+      question: (_q: string, cb: (a: string) => void) => cb("n"),
+      close: () => {},
+    } as any;
+    spyOn(readline, "createInterface").mockImplementation(() => mockInterface);
+
+    const result = await closeMultiModel({
+      sessionName: "test-session",
+      cleanupWorktrees: true,
+      force: false,
+    });
+    expect(result.success).toBe(false);
+    expect(result.error).toBe("Cleanup cancelled by user");
+  });
+
+  test("user confirms cleanup when not forced", async () => {
+    mockCommandResponses["tmux has-session -t test-session"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    const worktreePath =
+      "/home/user/.local/share/opencode/multi-model/test-session/model";
+    const worktreeListOutput = `worktree ${worktreePath}\nbranch refs/heads/opencode/test-session/model`;
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: worktreeListOutput,
+      stderr: "",
+    };
+
+    // Stub readline to simulate user confirming cleanup (answers "y")
+    const mockInterface = {
+      question: (_q: string, cb: (a: string) => void) => cb("y"),
+      close: () => {},
+    } as any;
+    spyOn(readline, "createInterface").mockImplementation(() => mockInterface);
+
+    // Freeze timestamp for deterministic tag name
+    const fixedDate = new Date("2023-01-01T00:00:00.000Z");
+    const OriginalDate = Date;
+    global.Date = class extends OriginalDate {
+      constructor() {
+        super();
+        // biome-ignore lint/correctness/noConstructorReturn: time-mocking required
+        return fixedDate;
+      }
+      override toISOString() {
+        return "2023-01-01T00:00:00.000Z";
+      }
+    } as any;
+
+    const result = await closeMultiModel({
+      sessionName: "test-session",
+      cleanupWorktrees: true,
+      force: false,
+    });
+
+    // Restore Date after invocation
+    global.Date = OriginalDate;
+
+    // Verify result indicates successful cleanup
+    expect(result.success).toBe(true);
+    expect(result.cleanupPerformed).toBe(true);
+    expect(result.worktreesRemoved).toEqual([worktreePath]);
+    expect(result.branchesDeleted).toEqual(["opencode/test-session/model"]);
+    expect(result.tagsCreated?.length).toBe(1);
+
+    // Verify the expected git commands were executed
+    expect(executedCommands).toContain(
+      `git worktree remove -f ${worktreePath}`,
+    );
+    expect(executedCommands).toContain(
+      `git branch -D opencode/test-session/model`,
+    );
+    const expectedTagCmd = `git tag archive/opencode/test-session/model-2023-01-01T00-00-00-000Z opencode/test-session/model`;
+    expect(executedCommands).toContain(expectedTagCmd);
+  });
+
+  test("warning when tag creation fails", async () => {
+    mockCommandResponses["tmux has-session -t test-session"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    const worktreePath =
+      "/home/user/.local/share/opencode/multi-model/test-session/model";
+    const worktreeListOutput = `worktree ${worktreePath}\nbranch refs/heads/opencode/test-session/model`;
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: worktreeListOutput,
+      stderr: "",
+    };
+    mockCommandResponses[`git worktree remove -f ${worktreePath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git branch -D opencode/test-session/model"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    // Tag command will fail
+    const fixedDate = new Date("2023-01-01T00:00:00.000Z");
+    const OriginalDate = Date;
+    global.Date = class extends OriginalDate {
+      constructor() {
+        super();
+        // biome-ignore lint/correctness/noConstructorReturn: time-mocking required
+        return fixedDate;
+      }
+      override toISOString() {
+        return "2023-01-01T00:00:00.000Z";
+      }
+    } as any;
+    const tagCommand = `git tag archive/opencode/test-session/model-2023-01-01T00-00-00-000Z opencode/test-session/model`;
+    mockCommandResponses[tagCommand] = {
+      ok: false,
+      stdout: "",
+      stderr: "tag error",
+    };
+
+    const result = await closeMultiModel({
+      sessionName: "test-session",
+      cleanupWorktrees: true,
+      force: true,
+    });
+    // Restore Date
+    global.Date = OriginalDate;
+
+    expect(result.success).toBe(true);
+    // Expect the warning message to be captured in instructions
+    expect(result.instructions.includes("Failed to create tag")).toBe(true);
+    expect(result.tagsCreated).toEqual([]);
+  });
+
+  test("cleanup works with unsanitized session name", async () => {
+    const unsanitized = "test session!";
+    const sanitized = "test-session"; // result of sanitizeName
+    // tmux lookup uses unsanitized name
+    mockCommandResponses[`tmux has-session -t ${unsanitized}`] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    const worktreePath = `/home/user/.local/share/opencode/multi-model/${sanitized}/model`;
+    const worktreeListOutput = `worktree ${worktreePath}\nbranch refs/heads/opencode/${sanitized}/model`;
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: worktreeListOutput,
+      stderr: "",
+    };
+    mockCommandResponses[`git worktree remove -f ${worktreePath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[`git branch -D opencode/${sanitized}/model`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      `rm -rf /home/user/.local/share/opencode/multi-model/${sanitized}`
+    ] = { ok: true, stdout: "", stderr: "" };
+
+    // Freeze timestamp for deterministic tag name
+    const fixedDate = new Date("2023-01-01T00:00:00.000Z");
+    const OriginalDate = Date;
+    global.Date = class extends OriginalDate {
+      constructor() {
+        super();
+        // biome-ignore lint/correctness/noConstructorReturn: time-mocking required
+        return fixedDate;
+      }
+      override toISOString() {
+        return "2023-01-01T00:00:00.000Z";
+      }
+    } as any;
+
+    const result = await closeMultiModel({
+      sessionName: unsanitized,
+      cleanupWorktrees: true,
+      force: true,
+    });
+    // Restore Date
+    global.Date = OriginalDate;
+
+    expect(result.success).toBe(true);
+    expect(result.cleanupPerformed).toBe(true);
+    expect(result.worktreesRemoved).toEqual([worktreePath]);
+    expect(result.branchesDeleted).toEqual([`opencode/${sanitized}/model`]);
+    expect(result.tagsCreated?.length).toBe(1);
+    // Verify that the commands used the sanitized paths for worktree removal and branch deletion
+    expect(executedCommands).toContain(
+      `git worktree remove -f ${worktreePath}`,
+    );
+    expect(executedCommands).toContain(
+      `git branch -D opencode/${sanitized}/model`,
+    );
+  });
+
+  test("tmux commands use sessionName, not safeSessionName", async () => {
+    const unsanitized = "my session!";
+    const sanitized = "my-session";
+    mockCommandResponses[`tmux has-session -t ${unsanitized}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[`tmux kill-session -t ${unsanitized}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    // No worktrees
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await closeMultiModel({
+      sessionName: unsanitized,
+      cleanupWorktrees: false,
+      force: false,
+    });
+    expect(result.success).toBe(true);
+    // Verify tmux commands used unsanitized name
+    expect(executedCommands).toContain(`tmux has-session -t ${unsanitized}`);
+    expect(executedCommands).toContain(`tmux kill-session -t ${unsanitized}`);
+    // Ensure sanitized name not used in tmux commands
+    expect(executedCommands.some((c) => c.includes(`-t ${sanitized}`))).toBe(
+      false,
+    );
+  });
+
+  test("skip archive tags when flag disabled", async () => {
+    mockCommandResponses["tmux has-session -t test-session"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    const worktreePath =
+      "/home/user/.local/share/opencode/multi-model/test-session/model";
+    const worktreeListOutput = `worktree ${worktreePath}\nbranch refs/heads/opencode/test-session/model`;
+    mockCommandResponses["git worktree list --porcelain"] = {
+      ok: true,
+      stdout: worktreeListOutput,
+      stderr: "",
+    };
+    mockCommandResponses[`git worktree remove -f ${worktreePath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses["git branch -D opencode/test-session/model"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      "rm -rf /home/user/.local/share/opencode/multi-model/test-session"
+    ] = { ok: true, stdout: "", stderr: "" };
+
+    const result = await closeMultiModel({
+      sessionName: "test-session",
+      cleanupWorktrees: true,
+      force: true,
+      createArchiveTags: false,
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.cleanupPerformed).toBe(true);
+    expect(result.worktreesRemoved).toEqual([worktreePath]);
+    expect(result.branchesDeleted).toEqual(["opencode/test-session/model"]);
+    expect(result.tagsCreated?.length ?? 0).toBe(0);
+    // Ensure no tag command was executed
+    expect(executedCommands.some((cmd) => cmd.startsWith("git tag"))).toBe(
+      false,
+    );
+  });
+});

tests/close_error.test.ts

@@ -0,0 +1,72 @@
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  mock,
+  spyOn,
+  test,
+} from "bun:test";
+import * as os from "node:os";
+import { closeMultiModel } from "../src/core/close";
+
+const originalBun$: typeof Bun.$ = (globalThis as any).Bun?.$;
+let mockCommandResponses: Record<
+  string,
+  { ok: boolean; stdout: string; stderr: string }
+> = {};
+let executedCommands: string[] = [];
+
+function setupMockBun$() {
+  const mockFn = mock((_strings: TemplateStringsArray, ...values: any[]) => {
+    const parts = values[0] as string[];
+    const cmd = parts.join(" ");
+    executedCommands.push(cmd);
+    // Simulate throwing error for a specific command
+    if (cmd === "git worktree list --porcelain") {
+      throw new Error("unexpected error");
+    }
+    const response = mockCommandResponses[cmd] ?? {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    return {
+      quiet: () => ({
+        nothrow: async () => ({
+          exitCode: response.ok ? 0 : 1,
+          stdout: { toString: () => response.stdout },
+          stderr: { toString: () => response.stderr },
+        }),
+      }),
+    };
+  });
+  (globalThis as any).Bun.$ = mockFn;
+  return mockFn;
+}
+
+function restoreOriginalBun$() {
+  (globalThis as any).Bun.$ = originalBun$;
+}
+
+describe("closeMultiModel unexpected error handling", () => {
+  beforeEach(() => {
+    spyOn(os, "homedir").mockReturnValue("/home/user");
+    mockCommandResponses = {};
+    executedCommands = [];
+    setupMockBun$();
+  });
+  afterEach(() => {
+    restoreOriginalBun$();
+  });
+
+  test("catches thrown error and returns failure", async () => {
+    const result = await closeMultiModel({
+      sessionName: "any-session",
+      cleanupWorktrees: false,
+      force: false,
+    });
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("unexpected error");
+  });
+});

tests/multi-model.test.ts

@@ -1,709 +0,0 @@
-import { expect, test, mock, spyOn, beforeEach, afterEach, describe } from "bun:test";
-import * as fs from "node:fs";
-import * as os from "node:os";
-import { launchMultiModel } from "../src/core/launch";
-import {
-  shellQuote,
-  normalizeModels,
-  findDuplicates,
-  createWindowBaseName,
-  createWindowPlans,
-  levenshtein,
-  suggestModels,
-  formatInvalidModelError,
-  sanitizeName,
-  runCommand,
-  getWorktreePath,
-  getSessionPath,
-  undoWorktree,
-  launchModelInWindow,
-  getWorktreesForSession,
-  getBinaryName,
-} from "../src/core/utils";
-
-let originalBun$: typeof Bun.$ = (globalThis as any).Bun?.$;
-let mockCommandResponses: Record<string, { ok: boolean; stdout: string; stderr: string }> = {};
-let executedCommands: string[] = [];
-
-function setupMockBun$() {
-  const mockFn = mock((strings: TemplateStringsArray, ...values: any[]) => {
-    const parts = values[0] as string[];
-    const commandSignature = parts.join(" ");
-
-    executedCommands.push(commandSignature);
-
-    return {
-      quiet: () => ({
-        nothrow: async () => {
-          const response = mockCommandResponses[commandSignature] ?? { ok: true, stdout: "", stderr: "" };
-          return {
-            exitCode: response.ok ? 0 : 1,
-            stdout: { toString: () => response.stdout },
-            stderr: { toString: () => response.stderr },
-          };
-        },
-      }),
-    };
-  });
-
-  (globalThis as any).Bun.$ = mockFn;
-  return mockFn;
-}
-
-function restoreOriginalBun$() {
-  (globalThis as any).Bun.$ = originalBun$;
-}
-
-describe("multi-model launch", () => {
-  let existsSyncMock: ReturnType<typeof spyOn>;
-  let bunMock: ReturnType<typeof setupMockBun$>;
-
-  beforeEach(() => {
-    spyOn(os, "homedir").mockReturnValue("/mock/home");
-    existsSyncMock = spyOn(fs, "existsSync").mockReturnValue(false);
-    bunMock = setupMockBun$();
-    executedCommands = [];
-
-    mockCommandResponses = {
-      "git rev-parse --is-inside-work-tree": { ok: true, stdout: "true", stderr: "" },
-      "command -v tmux": { ok: true, stdout: "/usr/bin/tmux", stderr: "" },
-      "command -v opencode": { ok: true, stdout: "/usr/bin/opencode", stderr: "" },
-      "opencode models": { ok: true, stdout: "openai/gpt-5.2\nanthropic/claude-3-5-sonnet", stderr: "" },
-      "tmux has-session -t test-session": { ok: false, stdout: "", stderr: "session not found" },
-      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2": { ok: false, stdout: "", stderr: "" },
-    };
-  });
-
-  afterEach(() => {
-    restoreOriginalBun$();
-  });
-
-  test("fails if session name is empty", async () => {
-    const result = await launchMultiModel({
-      sessionName: "",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Error: `sessionName` must not be empty.");
-    expect(executedCommands).toEqual([]);
-  });
-
-  test("fails if no models are provided", async () => {
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: [],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Error: Model names must not be empty.");
-    expect(executedCommands).toEqual([]);
-  });
-
-  test("fails if duplicate models are provided", async () => {
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2", "openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Duplicate model names are not allowed");
-    expect(executedCommands).toEqual([]);
-  });
-
-  test("fails if not inside a git repository", async () => {
-    mockCommandResponses["git rev-parse --is-inside-work-tree"] = { ok: false, stdout: "", stderr: "not a git repo" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Error: `multi-model` requires a git repository.");
-    expect(executedCommands).toEqual(["git rev-parse --is-inside-work-tree"]);
-  });
-
-  test("fails if tmux is not installed", async () => {
-    mockCommandResponses["command -v tmux"] = { ok: false, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Error: `tmux` is not installed or not on `PATH`.");
-    expect(executedCommands).toEqual([
-      "git rev-parse --is-inside-work-tree",
-      "command -v tmux"
-    ]);
-  });
-
-  test("fails if opencode is not installed", async () => {
-    mockCommandResponses["command -v opencode"] = { ok: false, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Error: `opencode` is not installed or not on `PATH`.");
-    expect(executedCommands).toEqual([
-      "git rev-parse --is-inside-work-tree",
-      "command -v tmux",
-      "command -v opencode"
-    ]);
-  });
-
-  test("fails if model name is not in allowlist", async () => {
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["invalid/model"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Error: Model name 'invalid/model' not found");
-    expect(executedCommands).toEqual([
-      "git rev-parse --is-inside-work-tree",
-      "command -v tmux",
-      "command -v opencode",
-      "opencode models"
-    ]);
-  });
-
-  test("fails if session already exists", async () => {
-    mockCommandResponses["tmux has-session -t test-session"] = { ok: true, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Error: Session already exists");
-    expect(executedCommands).toEqual([
-      "git rev-parse --is-inside-work-tree",
-      "command -v tmux",
-      "command -v opencode",
-      "opencode models",
-      "tmux has-session -t test-session"
-    ]);
-  });
-
-  test("successfully plans and executes tmux launch with single model", async () => {
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(true);
-    expect(result.instructions).toContain("Use `tmux attach -t test-session` to join session");
-    expect(executedCommands.some(c => c.startsWith("tmux new-session -d -s test-session -n gpt-5-2"))).toBe(true);
-    expect(executedCommands.some(c => c.startsWith("tmux send-keys -t test-session:gpt-5-2"))).toBe(true);
-  });
-
-  test("successfully launches multiple models", async () => {
-    mockCommandResponses["git show-ref --verify --quiet refs/heads/opencode/test-session/claude-3-5-sonnet"] = { ok: false, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2", "anthropic/claude-3-5-sonnet"],
-    });
-
-    expect(result.success).toBe(true);
-    expect(result.instructions).toContain("Use `tmux attach -t test-session` to join session");
-    expect(executedCommands.some(c => c.startsWith("tmux new-session -d -s test-session -n gpt-5-2"))).toBe(true);
-    expect(executedCommands.some(c => c.startsWith("tmux new-window -d -t test-session -n claude-3-5-sonnet"))).toBe(true);
-  });
-
-  test("sanitizes session name", async () => {
-    mockCommandResponses["tmux has-session -t test session!"] = { ok: false, stdout: "", stderr: "" };
-    mockCommandResponses["git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2"] = { ok: false, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test session!",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(true);
-    expect(result.instructions).toContain("Use `tmux attach -t test session!` to join session");
-    expect(executedCommands.some(c => c.startsWith("git worktree add -b opencode/test-session/gpt-5-2"))).toBe(true);
-  });
-
-  test("fails if tmux new-session fails for the first model and triggers undo", async () => {
-    mockCommandResponses["tmux new-session -d -s test-session -n gpt-5-2 -c /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2"] = { ok: false, stdout: "", stderr: "tmux error" };
-    mockCommandResponses["git worktree remove -f /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2"] = { ok: true, stdout: "", stderr: "" };
-    mockCommandResponses["git branch -D opencode/test-session/gpt-5-2"] = { ok: true, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Failed to create tmux session");
-    expect(executedCommands).toEqual([
-      "git rev-parse --is-inside-work-tree",
-      "command -v tmux",
-      "command -v opencode",
-      "opencode models",
-      "tmux has-session -t test-session",
-      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2",
-      "git worktree add -b opencode/test-session/gpt-5-2 /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2",
-      "tmux new-session -d -s test-session -n gpt-5-2 -c /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2",
-      "git worktree remove -f /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2",
-      "git branch -D opencode/test-session/gpt-5-2"
-    ]);
-  });
-
-  test("fails if worktree path exists for first model", async () => {
-    existsSyncMock.mockImplementation((path: string) => {
-      return path.includes("test-session/gpt-5-2");
-    });
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Worktree path already exists");
-    expect(executedCommands).toEqual([
-      "git rev-parse --is-inside-work-tree",
-      "command -v tmux",
-      "command -v opencode",
-      "opencode models",
-      "tmux has-session -t test-session"
-    ]);
-  });
-
-  test("fails if git branch exists for first model", async () => {
-    mockCommandResponses["git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2"] = { ok: true, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Branch 'opencode/test-session/gpt-5-2' already exists");
-    expect(executedCommands).toEqual([
-      "git rev-parse --is-inside-work-tree",
-      "command -v tmux",
-      "command -v opencode",
-      "opencode models",
-      "tmux has-session -t test-session",
-      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2"
-    ]);
-  });
-
-  test("fails if git worktree add fails for first model", async () => {
-    mockCommandResponses["git worktree add -b opencode/test-session/gpt-5-2 /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2"] = { ok: false, stdout: "", stderr: "git error" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(false);
-    expect(result.error).toContain("Failed to create worktree");
-    expect(executedCommands).toEqual([
-      "git rev-parse --is-inside-work-tree",
-      "command -v tmux",
-      "command -v opencode",
-      "opencode models",
-      "tmux has-session -t test-session",
-      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2",
-      "git worktree add -b opencode/test-session/gpt-5-2 /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2"
-    ]);
-  });
-
-  test("model name collision creates unique window names", async () => {
-    mockCommandResponses["opencode models"] = { ok: true, stdout: "openai/gpt-5.2\nanthropic/gpt-5.2", stderr: "" };
-    mockCommandResponses["git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2"] = { ok: false, stdout: "", stderr: "" };
-    mockCommandResponses["git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2-2"] = { ok: false, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: ["openai/gpt-5.2", "anthropic/gpt-5.2"],
-    });
-
-    expect(result.success).toBe(true);
-    expect(result.instructions).toContain("Use `tmux attach -t test-session` to join session");
-    expect(executedCommands.some(c => c.startsWith("tmux new-session -d -s test-session -n gpt-5-2"))).toBe(true);
-    expect(executedCommands.some(c => c.startsWith("tmux new-window -d -t test-session -n gpt-5-2-2"))).toBe(true);
-  });
-
-  test("long model name is truncated in window name", async () => {
-    const longModel = "verylongmodelfrontexampleprovider";
-    mockCommandResponses["opencode models"] = { ok: true, stdout: longModel, stderr: "" };
-    mockCommandResponses[`git show-ref --verify --quiet refs/heads/opencode/test-session/${longModel.slice(0, 24)}`] = { ok: false, stdout: "", stderr: "" };
-
-    const result = await launchMultiModel({
-      sessionName: "test-session",
-      models: [longModel],
-    });
-
-    expect(result.success).toBe(true);
-    expect(result.instructions).toContain("Use `tmux attach -t test-session` to join session");
-    const windowName = executedCommands.find(c => c.includes("tmux new-session"))?.match(/-n (\S+)/)?.[1];
-    expect(windowName?.length).toBeLessThanOrEqual(24);
-  });
-});
-
-describe("core utils", () => {
-  let bunMock: ReturnType<typeof setupMockBun$>;
-
-  beforeEach(() => {
-    spyOn(os, "homedir").mockReturnValue("/mock/home");
-    bunMock = setupMockBun$();
-    executedCommands = [];
-    mockCommandResponses = {};
-  });
-
-  afterEach(() => {
-    restoreOriginalBun$();
-  });
-
-  describe("shellQuote", () => {
-    test("normal string without special characters", () => {
-      expect(shellQuote("test")).toBe("'test'");
-    });
-
-    test("string with spaces", () => {
-      expect(shellQuote("test value")).toBe("'test value'");
-    });
-
-    test("string with single quotes", () => {
-      expect(shellQuote("test'value")).toBe("'test'\"'\"'value'");
-    });
-
-    test("string with multiple single quotes", () => {
-      expect(shellQuote("te's't'v'alue")).toBe("'te'\"'\"'s'\"'\"'t'\"'\"'v'\"'\"'alue'");
-    });
-
-    test("empty string", () => {
-      expect(shellQuote("")).toBe("''");
-    });
-  });
-
-  describe("normalizeModels", () => {
-    test("empty array", () => {
-      expect(normalizeModels([])).toEqual([]);
-    });
-
-    test("undefined input", () => {
-      expect(normalizeModels(undefined)).toEqual([]);
-    });
-
-    test("array with whitespace-only strings", () => {
-      expect(normalizeModels(["   ", "  "])).toEqual([]);
-    });
-
-    test("array with mixed valid models, padded models, and empty strings", () => {
-      expect(normalizeModels([" openai/gpt-5.2 ", "", " anthropic/claude "])).toEqual(["openai/gpt-5.2", "anthropic/claude"]);
-    });
-  });
-
-  describe("findDuplicates", () => {
-    test("array with no duplicates", () => {
-      expect(findDuplicates(["a", "b", "c"])).toEqual([]);
-    });
-
-    test("array with one duplicate pair", () => {
-      expect(findDuplicates(["a", "b", "a"])).toEqual(["a"]);
-    });
-
-    test("array with multiple different duplicates", () => {
-      expect(findDuplicates(["a", "b", "a", "c", "b"])).toEqual(["a", "b"]);
-    });
-
-    test("array with a single value repeated more than twice", () => {
-      expect(findDuplicates(["a", "a", "a"])).toEqual(["a"]);
-    });
-
-    test("verifying first-repeated-occurrence order", () => {
-      expect(findDuplicates(["x", "a", "b", "a", "x", "b"])).toEqual(["a", "x", "b"]);
-    });
-  });
-
-  describe("createWindowBaseName", () => {
-    test("normal model name without slashes", () => {
-      expect(createWindowBaseName("gpt-5-2")).toBe("gpt-5-2");
-    });
-
-    test("model with slashes", () => {
-      expect(createWindowBaseName("vendor/namespace/model")).toBe("model");
-    });
-
-    test("model exceeding WINDOW_NAME_LIMIT", () => {
-      const longName = "a".repeat(30);
-      expect(createWindowBaseName(longName)).toBe("aaaaaaaaaaaaaaaaaaaaaaaa");
-    });
-
-    test("model with special characters", () => {
-      expect(createWindowBaseName("OpenAI/GPT_4.0!")).toBe("gpt-4-0");
-    });
-
-    test("model made entirely of special characters", () => {
-      expect(createWindowBaseName("!@#$%^&*()")).toBe("model");
-    });
-  });
-
-  describe("createWindowPlans", () => {
-    test("single model", () => {
-      expect(createWindowPlans(["openai/gpt-5-2"])).toEqual([{ model: "openai/gpt-5-2", windowName: "gpt-5-2" }]);
-    });
-
-    test("two models with the same base name", () => {
-      expect(createWindowPlans(["openai/gpt-5-2", "anthropic/gpt-5-2"])).toEqual([
-        { model: "openai/gpt-5-2", windowName: "gpt-5-2" },
-        { model: "anthropic/gpt-5-2", windowName: "gpt-5-2-2" }
-      ]);
-    });
-
-    test("multiple collisions", () => {
-      const result = createWindowPlans(["a", "b", "c", "a", "b", "a"]);
-      expect(result[0]?.windowName).toBe("a");
-      expect(result[3]?.windowName).toBe("a-2");
-      expect(result[5]?.windowName).toBe("a-3");
-    });
-
-    test("truncation to accommodate suffix", () => {
-      const longBase = "a".repeat(23);
-      const result = createWindowPlans([longBase, "b"]);
-      expect(result[1]?.windowName.length).toBeLessThanOrEqual(24);
-    });
-  });
-
-  describe("levenshtein", () => {
-    test("identical strings", () => {
-      expect(levenshtein("test", "test")).toBe(0);
-    });
-
-    test("one substitution", () => {
-      expect(levenshtein("test", "tent")).toBe(1);
-    });
-
-    test("one insertion", () => {
-      expect(levenshtein("test", "tests")).toBe(1);
-    });
-
-    test("one deletion", () => {
-      expect(levenshtein("tests", "test")).toBe(1);
-    });
-
-    test("completely different strings", () => {
-      expect(levenshtein("abc", "xyz")).toBe(3);
-    });
-
-    test("one empty string", () => {
-      expect(levenshtein("", "test")).toBe(4);
-    });
-
-    test("both empty strings", () => {
-      expect(levenshtein("", "")).toBe(0);
-    });
-  });
-
-  describe("suggestModels", () => {
-    test("exact match", () => {
-      const result = suggestModels("gpt-5.2", ["gpt-5.2", "gpt-5.2-mini"]);
-      expect(result[0]).toBe("gpt-5.2");
-    });
-
-    test("fuzzy match/typo", () => {
-      expect(suggestModels("gpt5.4", ["gpt-5.4"])).toEqual(["gpt-5.4"]);
-    });
-
-    test("fuzzy match with contains boost", () => {
-      const suggestions = suggestModels("gpt4o", ["gpt-5.2", "gpt-5.2-mini"]);
-      expect(suggestions[0]).toBe("gpt-5.2");
-    });
-
-    test("maximum of 3 suggestions", () => {
-      const allowlist = ["gpt-5.2", "gpt-5.2-mini", "gpt-5.2-pro", "gpt-5.2-ultra"];
-      expect(suggestModels("gpt4o", allowlist).length).toBe(3);
-    });
-
-    test("sorting logic", () => {
-      const suggestions = suggestModels("abc", ["abc", "abd", "abe"]);
-      expect(suggestions).toEqual(["abc", "abd", "abe"]);
-    });
-  });
-
-  describe("formatInvalidModelError", () => {
-    test("single invalid model with available suggestions", () => {
-      const error = formatInvalidModelError(["gpt5.4"], ["gpt-5.4", "gpt-5.2"]);
-      expect(error).toContain("Model name 'gpt5.4' not found");
-      expect(error).toContain("Did you mean");
-    });
-
-    test("single invalid model without close matches", () => {
-      const error = formatInvalidModelError(["xyz"], ["abc", "def"]);
-      expect(error).toContain("Model name 'xyz' not found");
-      expect(error).toContain("Did you mean");
-    });
-
-    test("multiple invalid models", () => {
-      const error = formatInvalidModelError(["xyz", "abc"], ["def"]);
-      expect(error).toContain("Model names not found");
-      expect(error).toContain("'xyz'");
-      expect(error).toContain("'abc'");
-    });
-  });
-
-  describe("sanitizeName", () => {
-    test("normal alphanumeric name", () => {
-      expect(sanitizeName("test-session")).toBe("test-session");
-    });
-
-    test("name with spaces and special chars", () => {
-      expect(sanitizeName("test session!")).toBe("test-session");
-    });
-
-    test("name with consecutive hyphens", () => {
-      expect(sanitizeName("test--session")).toBe("test-session");
-    });
-
-    test("name with leading/trailing hyphens", () => {
-      expect(sanitizeName("-test-session-")).toBe("test-session");
-    });
-  });
-
-  describe("runCommand", () => {
-    test("returns ok true for successful command", async () => {
-      mockCommandResponses["echo hello"] = { ok: true, stdout: "hello", stderr: "" };
-      const result = await runCommand(["echo", "hello"]);
-      expect(result.ok).toBe(true);
-      expect(result.stdout).toBe("hello");
-      expect(result.stderr).toBe("");
-    });
-
-    test("returns ok false for failed command", async () => {
-      mockCommandResponses["false"] = { ok: false, stdout: "", stderr: "error" };
-      const result = await runCommand(["false"]);
-      expect(result.ok).toBe(false);
-      expect(result.stderr).toBe("error");
-    });
-  });
-
-  describe("getWorktreePath", () => {
-    test("returns correct worktree path", () => {
-      spyOn(os, "homedir").mockReturnValue("/home/user");
-      const result = getWorktreePath("my-session", "gpt-5.2");
-      expect(result).toBe("/home/user/.local/share/opencode/multi-model/my-session/gpt-5.2");
-    });
-
-    test("handles nested session names", () => {
-      spyOn(os, "homedir").mockReturnValue("/home/user");
-      const result = getWorktreePath("parent/child", "window");
-      expect(result).toBe("/home/user/.local/share/opencode/multi-model/parent/child/window");
-    });
-  });
-
-  describe("getSessionPath", () => {
-    test("returns correct session path", () => {
-      spyOn(os, "homedir").mockReturnValue("/home/user");
-      const result = getSessionPath("my-session");
-      expect(result).toBe("/home/user/.local/share/opencode/multi-model/my-session");
-    });
-  });
-
-  describe("undoWorktree", () => {
-    test("returns empty array on success", async () => {
-      mockCommandResponses["git worktree remove -f /path/to/worktree"] = { ok: true, stdout: "", stderr: "" };
-      mockCommandResponses["git branch -D opencode/session/window"] = { ok: true, stdout: "", stderr: "" };
-
-      const errors = await undoWorktree("/path/to/worktree", "opencode/session/window");
-      expect(errors).toEqual([]);
-    });
-
-    test("returns error when worktree remove fails", async () => {
-      mockCommandResponses["git worktree remove -f /path/to/worktree"] = { ok: false, stdout: "", stderr: "remove failed" };
-      mockCommandResponses["git branch -D opencode/session/window"] = { ok: true, stdout: "", stderr: "" };
-
-      const errors = await undoWorktree("/path/to/worktree", "opencode/session/window");
-      expect(errors.length).toBe(1);
-      expect(errors[0]).toContain("Failed to remove worktree");
-    });
-
-    test("returns error when branch delete fails", async () => {
-      mockCommandResponses["git worktree remove -f /path/to/worktree"] = { ok: true, stdout: "", stderr: "" };
-      mockCommandResponses["git branch -D opencode/session/window"] = { ok: false, stdout: "", stderr: "branch delete failed" };
-
-      const errors = await undoWorktree("/path/to/worktree", "opencode/session/window");
-      expect(errors.length).toBe(1);
-      expect(errors[0]).toContain("Failed to delete branch");
-    });
-
-    test("returns both errors when both operations fail", async () => {
-      mockCommandResponses["git worktree remove -f /path/to/worktree"] = { ok: false, stdout: "", stderr: "remove failed" };
-      mockCommandResponses["git branch -D opencode/session/window"] = { ok: false, stdout: "", stderr: "branch delete failed" };
-
-      const errors = await undoWorktree("/path/to/worktree", "opencode/session/window");
-      expect(errors.length).toBe(2);
-    });
-  });
-
-  describe("launchModelInWindow", () => {
-    test("sends correct tmux command", async () => {
-      mockCommandResponses["tmux send-keys -t session:window opencode --model 'openai/gpt-5.2' C-m"] = { ok: true, stdout: "", stderr: "" };
-
-      const result = await launchModelInWindow("session", { model: "openai/gpt-5.2", windowName: "window" });
-      expect(result.ok).toBe(true);
-      expect(executedCommands).toContain("tmux send-keys -t session:window opencode --model 'openai/gpt-5.2' C-m");
-    });
-
-    test("uses custom binary name", async () => {
-      mockCommandResponses["tmux send-keys -t session:window kilo --model 'openai/gpt-5.2' C-m"] = { ok: true, stdout: "", stderr: "" };
-
-      const result = await launchModelInWindow("session", { model: "openai/gpt-5.2", windowName: "window" }, "kilo");
-      expect(result.ok).toBe(true);
-      expect(executedCommands).toContain("tmux send-keys -t session:window kilo --model 'openai/gpt-5.2' C-m");
-    });
-  });
-
-  describe("getWorktreesForSession", () => {
-    test("returns session-specific worktrees", async () => {
-      spyOn(os, "homedir").mockReturnValue("/home/user");
-      mockCommandResponses["git worktree list --porcelain"] = {
-        ok: true,
-        stdout: "worktree /home/user/.local/share/opencode/multi-model/my-session/gpt-5.2\nbranch refs/heads/opencode/my-session/gpt-5.2\n\nworktree /home/user/other-repo\nbranch refs/heads/main",
-        stderr: "",
-      };
-
-      const worktrees = await getWorktreesForSession("my-session");
-      expect(worktrees.length).toBe(1);
-      expect(worktrees[0]?.path).toBe("/home/user/.local/share/opencode/multi-model/my-session/gpt-5.2");
-      expect(worktrees[0]?.branch).toBe("opencode/my-session/gpt-5.2");
-    });
-
-    test("returns empty array when no matching worktrees", async () => {
-      spyOn(os, "homedir").mockReturnValue("/home/user");
-      mockCommandResponses["git worktree list --porcelain"] = {
-        ok: true,
-        stdout: "worktree /home/user/other-repo\nbranch refs/heads/main",
-        stderr: "",
-      };
-
-      const worktrees = await getWorktreesForSession("my-session");
-      expect(worktrees).toEqual([]);
-    });
-  });
-
-  describe("getBinaryName", () => {
-    test("returns default 'opencode' when env var not set", () => {
-      delete process.env.OPENCODE_MULTI_MODEL_BINARY;
-      expect(getBinaryName()).toBe("opencode");
-    });
-
-    test("returns env var value when set", () => {
-      process.env.OPENCODE_MULTI_MODEL_BINARY = "kilo";
-      expect(getBinaryName()).toBe("kilo");
-      delete process.env.OPENCODE_MULTI_MODEL_BINARY;
-    });
-  });
-});

tests/open.test.ts

@@ -0,0 +1,526 @@
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  mock,
+  spyOn,
+  test,
+} from "bun:test";
+import * as fs from "node:fs";
+import * as os from "node:os";
+import { openMultiModel } from "../src/core/open";
+
+const originalBun$: typeof Bun.$ = (globalThis as any).Bun?.$;
+let mockCommandResponses: Record<
+  string,
+  { ok: boolean; stdout: string; stderr: string }
+> = {};
+let executedCommands: string[] = [];
+
+function setupMockBun$() {
+  const mockFn = mock((_strings: TemplateStringsArray, ...values: any[]) => {
+    const parts = values[0] as string[];
+    const commandSignature = parts.join(" ");
+
+    executedCommands.push(commandSignature);
+
+    return {
+      quiet: () => ({
+        nothrow: async () => {
+          const response = mockCommandResponses[commandSignature] ?? {
+            ok: true,
+            stdout: "",
+            stderr: "",
+          };
+          return {
+            exitCode: response.ok ? 0 : 1,
+            stdout: { toString: () => response.stdout },
+            stderr: { toString: () => response.stderr },
+          };
+        },
+      }),
+    };
+  });
+
+  (globalThis as any).Bun.$ = mockFn;
+  return mockFn;
+}
+
+function restoreOriginalBun$() {
+  (globalThis as any).Bun.$ = originalBun$;
+}
+
+describe("multi-model launch", () => {
+  let existsSyncMock: ReturnType<typeof spyOn>;
+  let _bunMock: ReturnType<typeof setupMockBun$>;
+
+  beforeEach(() => {
+    spyOn(os, "homedir").mockReturnValue("/mock/home");
+    existsSyncMock = spyOn(fs, "existsSync").mockReturnValue(false);
+    _bunMock = setupMockBun$();
+    executedCommands = [];
+
+    mockCommandResponses = {
+      "git rev-parse --is-inside-work-tree": {
+        ok: true,
+        stdout: "true",
+        stderr: "",
+      },
+      "command -v tmux": { ok: true, stdout: "/usr/bin/tmux", stderr: "" },
+      "command -v opencode": {
+        ok: true,
+        stdout: "/usr/bin/opencode",
+        stderr: "",
+      },
+      "opencode models": {
+        ok: true,
+        stdout: "openai/gpt-5.2\nanthropic/claude-3-5-sonnet",
+        stderr: "",
+      },
+      "tmux has-session -t test-session": {
+        ok: false,
+        stdout: "",
+        stderr: "session not found",
+      },
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2":
+        { ok: false, stdout: "", stderr: "" },
+    };
+  });
+
+  afterEach(() => {
+    restoreOriginalBun$();
+  });
+
+  test("fails if session name is empty", async () => {
+    const result = await openMultiModel({
+      sessionName: "",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Error: `sessionName` must not be empty.");
+    expect(executedCommands).toEqual([]);
+  });
+
+  test("fails if no models are provided", async () => {
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: [],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Error: Model names must not be empty.");
+    expect(executedCommands).toEqual([]);
+  });
+
+  test("fails if duplicate models are provided", async () => {
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2", "openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Duplicate model names are not allowed");
+    expect(executedCommands).toEqual([]);
+  });
+
+  test("fails if not inside a git repository", async () => {
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: false,
+      stdout: "",
+      stderr: "not a git repo",
+    };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain(
+      "Error: `multi-model` requires a git repository.",
+    );
+    expect(executedCommands).toEqual(["git rev-parse --is-inside-work-tree"]);
+  });
+
+  test("fails if tmux is not installed", async () => {
+    mockCommandResponses["command -v tmux"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain(
+      "Error: `tmux` is not installed or not on `PATH`.",
+    );
+    expect(executedCommands).toEqual([
+      "git rev-parse --is-inside-work-tree",
+      "command -v tmux",
+    ]);
+  });
+
+  test("fails if opencode is not installed", async () => {
+    mockCommandResponses["command -v opencode"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain(
+      "Error: `opencode` is not installed or not on `PATH`.",
+    );
+    expect(executedCommands).toEqual([
+      "git rev-parse --is-inside-work-tree",
+      "command -v tmux",
+      "command -v opencode",
+    ]);
+  });
+
+  test("fails if model name is not in allowlist", async () => {
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["invalid/model"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain(
+      "Error: Model name 'invalid/model' not found",
+    );
+    expect(executedCommands).toEqual([
+      "git rev-parse --is-inside-work-tree",
+      "command -v tmux",
+      "command -v opencode",
+      "opencode models",
+    ]);
+  });
+
+  test("fails if session already exists", async () => {
+    mockCommandResponses["tmux has-session -t test-session"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Error: Session already exists");
+    expect(executedCommands).toEqual([
+      "git rev-parse --is-inside-work-tree",
+      "command -v tmux",
+      "command -v opencode",
+      "opencode models",
+      "tmux has-session -t test-session",
+    ]);
+  });
+
+  test("successfully plans and executes tmux launch with single model", async () => {
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain(
+      "Use `tmux attach -t test-session` to join session",
+    );
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith("tmux new-session -d -s test-session -n gpt-5-2"),
+      ),
+    ).toBe(true);
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith("tmux send-keys -t test-session:gpt-5-2"),
+      ),
+    ).toBe(true);
+  });
+
+  test("successfully launches multiple models", async () => {
+    mockCommandResponses[
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/claude-3-5-sonnet"
+    ] = { ok: false, stdout: "", stderr: "" };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2", "anthropic/claude-3-5-sonnet"],
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain(
+      "Use `tmux attach -t test-session` to join session",
+    );
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith("tmux new-session -d -s test-session -n gpt-5-2"),
+      ),
+    ).toBe(true);
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith("tmux new-window -d -t test-session -n claude-3-5-sonnet"),
+      ),
+    ).toBe(true);
+  });
+
+  test("sanitizes session name", async () => {
+    mockCommandResponses["tmux has-session -t test session!"] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2"
+    ] = { ok: false, stdout: "", stderr: "" };
+
+    const result = await openMultiModel({
+      sessionName: "test session!",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain(
+      "Use `tmux attach -t test session!` to join session",
+    );
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith("git worktree add -b opencode/test-session/gpt-5-2"),
+      ),
+    ).toBe(true);
+  });
+
+  test("uses sessionName for tmux commands, not safeSessionName", async () => {
+    const unsanitized = "my awesome session!!";
+    const sanitized = "my-awesome-session";
+    mockCommandResponses[`tmux has-session -t ${unsanitized}`] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/opencode/${sanitized}/gpt-5-2`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `git worktree add -b opencode/${sanitized}/gpt-5-2 /mock/home/.local/share/opencode/multi-model/${sanitized}/gpt-5-2`
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux new-session -d -s ${unsanitized} -n gpt-5-2 -c /mock/home/.local/share/opencode/multi-model/${sanitized}/gpt-5-2`
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux send-keys -t ${unsanitized}:gpt-5-2 opencode --model 'openai/gpt-5.2' C-m`
+    ] = { ok: true, stdout: "", stderr: "" };
+
+    const result = await openMultiModel({
+      sessionName: unsanitized,
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(true);
+    // tmux commands should use unsanitized name
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith(`tmux has-session -t ${unsanitized}`),
+      ),
+    ).toBe(true);
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith(`tmux new-session -d -s ${unsanitized}`),
+      ),
+    ).toBe(true);
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith(`tmux send-keys -t ${unsanitized}:`),
+      ),
+    ).toBe(true);
+    // sanitized name should NOT appear in tmux commands
+    expect(executedCommands.some((c) => c.includes(`-t ${sanitized}`))).toBe(
+      false,
+    );
+    // git branches and paths should use sanitized name
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith(`git worktree add -b opencode/${sanitized}/gpt-5-2`),
+      ),
+    ).toBe(true);
+  });
+
+  test("fails if tmux new-session fails for the first model and triggers undo", async () => {
+    mockCommandResponses[
+      "tmux new-session -d -s test-session -n gpt-5-2 -c /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2"
+    ] = { ok: false, stdout: "", stderr: "tmux error" };
+    mockCommandResponses[
+      "git worktree remove -f /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2"
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses["git branch -D opencode/test-session/gpt-5-2"] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Failed to create tmux session");
+    expect(executedCommands).toEqual([
+      "git rev-parse --is-inside-work-tree",
+      "command -v tmux",
+      "command -v opencode",
+      "opencode models",
+      "tmux has-session -t test-session",
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2",
+      "git worktree add -b opencode/test-session/gpt-5-2 /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2",
+      "tmux new-session -d -s test-session -n gpt-5-2 -c /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2",
+      "git worktree remove -f /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2",
+      "git branch -D opencode/test-session/gpt-5-2",
+    ]);
+  });
+
+  test("fails if worktree path exists for first model", async () => {
+    existsSyncMock.mockImplementation((path: string) => {
+      return path.includes("test-session/gpt-5-2");
+    });
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Worktree path already exists");
+    expect(executedCommands).toEqual([
+      "git rev-parse --is-inside-work-tree",
+      "command -v tmux",
+      "command -v opencode",
+      "opencode models",
+      "tmux has-session -t test-session",
+    ]);
+  });
+
+  test("fails if git branch exists for first model", async () => {
+    mockCommandResponses[
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2"
+    ] = { ok: true, stdout: "", stderr: "" };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain(
+      "Branch 'opencode/test-session/gpt-5-2' already exists",
+    );
+    expect(executedCommands).toEqual([
+      "git rev-parse --is-inside-work-tree",
+      "command -v tmux",
+      "command -v opencode",
+      "opencode models",
+      "tmux has-session -t test-session",
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2",
+    ]);
+  });
+
+  test("fails if git worktree add fails for first model", async () => {
+    mockCommandResponses[
+      "git worktree add -b opencode/test-session/gpt-5-2 /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2"
+    ] = { ok: false, stdout: "", stderr: "git error" };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Failed to create worktree");
+    expect(executedCommands).toEqual([
+      "git rev-parse --is-inside-work-tree",
+      "command -v tmux",
+      "command -v opencode",
+      "opencode models",
+      "tmux has-session -t test-session",
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2",
+      "git worktree add -b opencode/test-session/gpt-5-2 /mock/home/.local/share/opencode/multi-model/test-session/gpt-5-2",
+    ]);
+  });
+
+  test("model name collision creates unique window names", async () => {
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: "openai/gpt-5.2\nanthropic/gpt-5.2",
+      stderr: "",
+    };
+    mockCommandResponses[
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2"
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[
+      "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-5-2-2"
+    ] = { ok: false, stdout: "", stderr: "" };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: ["openai/gpt-5.2", "anthropic/gpt-5.2"],
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain(
+      "Use `tmux attach -t test-session` to join session",
+    );
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith("tmux new-session -d -s test-session -n gpt-5-2"),
+      ),
+    ).toBe(true);
+    expect(
+      executedCommands.some((c) =>
+        c.startsWith("tmux new-window -d -t test-session -n gpt-5-2-2"),
+      ),
+    ).toBe(true);
+  });
+
+  test("long model name is truncated in window name", async () => {
+    const longModel = "verylongmodelfrontexampleprovider";
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: longModel,
+      stderr: "",
+    };
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/opencode/test-session/${longModel.slice(0, 24)}`
+    ] = { ok: false, stdout: "", stderr: "" };
+
+    const result = await openMultiModel({
+      sessionName: "test-session",
+      models: [longModel],
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain(
+      "Use `tmux attach -t test-session` to join session",
+    );
+    const windowName = executedCommands
+      .find((c) => c.includes("tmux new-session"))
+      ?.match(/-n (\S+)/)?.[1];
+    expect(windowName?.length).toBeLessThanOrEqual(24);
+  });
+});
+
+// ----------
+// Core utils tests remain in a separate file.

tests/open_error.test.ts

@@ -0,0 +1,539 @@
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  mock,
+  spyOn,
+  test,
+} from "bun:test";
+import * as fs from "node:fs";
+import * as os from "node:os";
+import { openMultiModel } from "../src/core/open";
+
+const originalBun$: typeof Bun.$ = (globalThis as any).Bun?.$;
+let mockCommandResponses: Record<
+  string,
+  { ok: boolean; stdout: string; stderr: string }
+> = {};
+let executedCommands: string[] = [];
+
+function setupMockBun$() {
+  const mockFn = mock((_strings: TemplateStringsArray, ...values: any[]) => {
+    const parts = values[0] as string[];
+    const cmd = parts.join(" ");
+    executedCommands.push(cmd);
+    const response = mockCommandResponses[cmd] ?? {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    return {
+      quiet: () => ({
+        nothrow: async () => ({
+          exitCode: response.ok ? 0 : 1,
+          stdout: { toString: () => response.stdout },
+          stderr: { toString: () => response.stderr },
+        }),
+      }),
+    };
+  });
+  (globalThis as any).Bun.$ = mockFn;
+  return mockFn;
+}
+
+function restoreOriginalBun$() {
+  (globalThis as any).Bun.$ = originalBun$;
+}
+
+describe("openMultiModel error paths", () => {
+  beforeEach(() => {
+    spyOn(os, "homedir").mockReturnValue("/mock/home");
+    mockCommandResponses = {};
+    executedCommands = [];
+    setupMockBun$();
+  });
+  afterEach(() => {
+    restoreOriginalBun$();
+  });
+
+  test("fails when model list command fails", async () => {
+    const session = "sess";
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: true,
+      stdout: "true",
+      stderr: "",
+    };
+    mockCommandResponses["command -v tmux"] = {
+      ok: true,
+      stdout: "tmux",
+      stderr: "",
+    };
+    mockCommandResponses["command -v opencode"] = {
+      ok: true,
+      stdout: "opencode",
+      stderr: "",
+    };
+    mockCommandResponses["opencode models"] = {
+      ok: false,
+      stdout: "",
+      stderr: "model error",
+    };
+
+    const result = await openMultiModel({
+      sessionName: session,
+      models: ["openai/gpt-5.2"],
+      binaryName: "opencode",
+      mode: "cli",
+    });
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Failed to load valid models");
+  });
+
+  test("fails when duplicate models provided", async () => {
+    const session = "dup";
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: true,
+      stdout: "true",
+      stderr: "",
+    };
+    mockCommandResponses["command -v tmux"] = {
+      ok: true,
+      stdout: "tmux",
+      stderr: "",
+    };
+    mockCommandResponses["command -v opencode"] = {
+      ok: true,
+      stdout: "opencode",
+      stderr: "",
+    };
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: "openai/gpt-5.2",
+      stderr: "",
+    };
+
+    const result = await openMultiModel({
+      sessionName: session,
+      models: ["openai/gpt-5.2", "openai/gpt-5.2"],
+      binaryName: "opencode",
+      mode: "cli",
+    });
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Duplicate model names are not allowed");
+  });
+
+  test("fails when session already exists", async () => {
+    const session = "existing";
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: true,
+      stdout: "true",
+      stderr: "",
+    };
+    mockCommandResponses["command -v tmux"] = {
+      ok: true,
+      stdout: "tmux",
+      stderr: "",
+    };
+    mockCommandResponses["command -v opencode"] = {
+      ok: true,
+      stdout: "opencode",
+      stderr: "",
+    };
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: "openai/gpt-5.2",
+      stderr: "",
+    };
+    mockCommandResponses[`tmux has-session -t ${session}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+
+    const result = await openMultiModel({
+      sessionName: session,
+      models: ["openai/gpt-5.2"],
+      binaryName: "opencode",
+      mode: "cli",
+    });
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("Session already exists");
+  });
+
+  test("second model fails because branch already exists", async () => {
+    const session = "sess-add";
+    const binary = "opencode";
+    const models = ["openai/gpt-5.2", "anthropic/gpt-5-2"];
+    // common mocks
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: true,
+      stdout: "true",
+      stderr: "",
+    };
+    mockCommandResponses["command -v tmux"] = {
+      ok: true,
+      stdout: "tmux",
+      stderr: "",
+    };
+    mockCommandResponses["command -v opencode"] = {
+      ok: true,
+      stdout: "opencode",
+      stderr: "",
+    };
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: models.join("\n"),
+      stderr: "",
+    };
+    mockCommandResponses[`tmux has-session -t ${session}`] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    // first model success
+    const firstBranch = `opencode/${session}/gpt-5-2`;
+    const firstPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${firstBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[`git worktree add -b ${firstBranch} ${firstPath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      `tmux new-session -d -s ${session} -n gpt-5-2 -c ${firstPath}`
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux send-keys -t ${session}:gpt-5-2 ${binary} --model 'openai/gpt-5.2' C-m`
+    ] = { ok: true, stdout: "", stderr: "" };
+    // second model branch exists
+    const secondBranch = `opencode/${session}/gpt-5-2-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${secondBranch}`
+    ] = { ok: true, stdout: "", stderr: "" };
+    const result = await openMultiModel({
+      sessionName: session,
+      models,
+      binaryName: binary,
+      mode: "cli",
+    });
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain("Failed: anthropic/gpt-5-2 (Branch");
+    expect(result.windows).toContain("gpt-5-2");
+    expect(result.windows).toContain("gpt-5-2-2");
+  });
+
+  test("second model worktree creation fails", async () => {
+    const session = "sess-wt";
+    const binary = "opencode";
+    const models = ["openai/gpt-5.2", "anthropic/gpt-5-2"];
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: true,
+      stdout: "true",
+      stderr: "",
+    };
+    mockCommandResponses["command -v tmux"] = {
+      ok: true,
+      stdout: "tmux",
+      stderr: "",
+    };
+    mockCommandResponses["command -v opencode"] = {
+      ok: true,
+      stdout: "opencode",
+      stderr: "",
+    };
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: models.join("\n"),
+      stderr: "",
+    };
+    mockCommandResponses[`tmux has-session -t ${session}`] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    // first model success
+    const firstBranch = `opencode/${session}/gpt-5-2`;
+    const firstPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${firstBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[`git worktree add -b ${firstBranch} ${firstPath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      `tmux new-session -d -s ${session} -n gpt-5-2 -c ${firstPath}`
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux send-keys -t ${session}:gpt-5-2 ${binary} --model 'openai/gpt-5.2' C-m`
+    ] = { ok: true, stdout: "", stderr: "" };
+    // second model fails worktree
+    const secondBranch = `opencode/${session}/gpt-5-2-2`;
+    const secondPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${secondBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[`git worktree add -b ${secondBranch} ${secondPath}`] =
+      { ok: false, stdout: "", stderr: "wt error" };
+    mockCommandResponses[`git worktree remove -f ${secondPath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[`git branch -D ${secondBranch}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    const result = await openMultiModel({
+      sessionName: session,
+      models,
+      binaryName: binary,
+      mode: "cli",
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain("Error: Created tmux session");
+    expect(result.instructions).toContain("Failed: anthropic/gpt-5-2");
+    expect(result.windows).toContain("gpt-5-2");
+    expect(result.windows).toContain("gpt-5-2-2");
+  });
+
+  test("second model window creation fails", async () => {
+    const session = "sess-win";
+    const binary = "opencode";
+    const models = ["openai/gpt-5.2", "anthropic/gpt-5-2"];
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: true,
+      stdout: "true",
+      stderr: "",
+    };
+    mockCommandResponses["command -v tmux"] = {
+      ok: true,
+      stdout: "tmux",
+      stderr: "",
+    };
+    mockCommandResponses["command -v opencode"] = {
+      ok: true,
+      stdout: "opencode",
+      stderr: "",
+    };
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: models.join("\n"),
+      stderr: "",
+    };
+    mockCommandResponses[`tmux has-session -t ${session}`] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    // first model success
+    const firstBranch = `opencode/${session}/gpt-5-2`;
+    const firstPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${firstBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[`git worktree add -b ${firstBranch} ${firstPath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      `tmux new-session -d -s ${session} -n gpt-5-2 -c ${firstPath}`
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux send-keys -t ${session}:gpt-5-2 ${binary} --model 'openai/gpt-5.2' C-m`
+    ] = { ok: true, stdout: "", stderr: "" };
+    // second model window failure
+    const secondBranch = `opencode/${session}/gpt-5-2-2`;
+    const secondPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${secondBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[`git worktree add -b ${secondBranch} ${secondPath}`] =
+      { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux new-window -d -t ${session} -n gpt-5-2-2 -c ${secondPath}`
+    ] = { ok: false, stdout: "", stderr: "win err" };
+    mockCommandResponses[`git worktree remove -f ${secondPath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[`git branch -D ${secondBranch}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    const result = await openMultiModel({
+      sessionName: session,
+      models,
+      binaryName: binary,
+      mode: "cli",
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain("Error: Created tmux session");
+    expect(result.instructions).toContain("Failed: anthropic/gpt-5-2");
+    expect(result.windows).toContain("gpt-5-2");
+    expect(result.windows).toContain("gpt-5-2-2");
+  });
+
+  test("second model launch command fails", async () => {
+    const session = "sess-launch";
+    const binary = "opencode";
+    const models = ["openai/gpt-5.2", "anthropic/gpt-5-2"];
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: true,
+      stdout: "true",
+      stderr: "",
+    };
+    mockCommandResponses["command -v tmux"] = {
+      ok: true,
+      stdout: "tmux",
+      stderr: "",
+    };
+    mockCommandResponses["command -v opencode"] = {
+      ok: true,
+      stdout: "opencode",
+      stderr: "",
+    };
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: models.join("\n"),
+      stderr: "",
+    };
+    mockCommandResponses[`tmux has-session -t ${session}`] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    // first model success
+    const firstBranch = `opencode/${session}/gpt-5-2`;
+    const firstPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${firstBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[`git worktree add -b ${firstBranch} ${firstPath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      `tmux new-session -d -s ${session} -n gpt-5-2 -c ${firstPath}`
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux send-keys -t ${session}:gpt-5-2 ${binary} --model 'openai/gpt-5.2' C-m`
+    ] = { ok: true, stdout: "", stderr: "" };
+    // second model launch fails
+    const secondBranch = `opencode/${session}/gpt-5-2-2`;
+    const secondPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${secondBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[`git worktree add -b ${secondBranch} ${secondPath}`] =
+      { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux new-window -d -t ${session} -n gpt-5-2-2 -c ${secondPath}`
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux send-keys -t ${session}:gpt-5-2-2 ${binary} --model 'anthropic/gpt-5-2' C-m`
+    ] = { ok: false, stdout: "", stderr: "launch err" };
+    mockCommandResponses[`git worktree remove -f ${secondPath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[`git branch -D ${secondBranch}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    const result = await openMultiModel({
+      sessionName: session,
+      models,
+      binaryName: binary,
+      mode: "cli",
+    });
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain(
+      "Failed: anthropic/gpt-5-2 (launch err",
+    );
+    expect(result.windows).toContain("gpt-5-2");
+    expect(result.windows).toContain("gpt-5-2-2");
+  });
+
+  test("second model worktree path already exists", async () => {
+    const session = "sess-wtpath";
+    const binary = "opencode";
+    const models = ["openai/gpt-5.2", "anthropic/gpt-5-2"];
+    mockCommandResponses["git rev-parse --is-inside-work-tree"] = {
+      ok: true,
+      stdout: "true",
+      stderr: "",
+    };
+    mockCommandResponses["command -v tmux"] = {
+      ok: true,
+      stdout: "tmux",
+      stderr: "",
+    };
+    mockCommandResponses["command -v opencode"] = {
+      ok: true,
+      stdout: "opencode",
+      stderr: "",
+    };
+    mockCommandResponses["opencode models"] = {
+      ok: true,
+      stdout: models.join("\n"),
+      stderr: "",
+    };
+    mockCommandResponses[`tmux has-session -t ${session}`] = {
+      ok: false,
+      stdout: "",
+      stderr: "",
+    };
+    // first model success
+    const firstBranch = `opencode/${session}/gpt-5-2`;
+    const firstPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${firstBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    mockCommandResponses[`git worktree add -b ${firstBranch} ${firstPath}`] = {
+      ok: true,
+      stdout: "",
+      stderr: "",
+    };
+    mockCommandResponses[
+      `tmux new-session -d -s ${session} -n gpt-5-2 -c ${firstPath}`
+    ] = { ok: true, stdout: "", stderr: "" };
+    mockCommandResponses[
+      `tmux send-keys -t ${session}:gpt-5-2 ${binary} --model 'openai/gpt-5.2' C-m`
+    ] = { ok: true, stdout: "", stderr: "" };
+    // second model path exists
+    const secondBranch = `opencode/${session}/gpt-5-2-2`;
+    const secondPath = `/mock/home/.local/share/opencode/multi-model/${session}/gpt-5-2-2`;
+    mockCommandResponses[
+      `git show-ref --verify --quiet refs/heads/${secondBranch}`
+    ] = { ok: false, stdout: "", stderr: "" };
+    // mock fs existsSync to return true for secondPath
+    spyOn(fs, "existsSync").mockImplementation((p) => p === secondPath);
+    const result = await openMultiModel({
+      sessionName: session,
+      models,
+      binaryName: binary,
+      mode: "cli",
+    });
+    expect(result.success).toBe(true);
+    expect(result.instructions).toContain("Error: Created tmux session");
+    expect(result.instructions).toContain(
+      "Failed: anthropic/gpt-5-2 (Worktree path already exists at",
+    );
+    expect(result.windows).toContain("gpt-5-2");
+    expect(result.windows).toContain("gpt-5-2-2");
+  });
+});

tests/utils.test.ts

@@ -0,0 +1,487 @@
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  mock,
+  spyOn,
+  test,
+} from "bun:test";
+import * as os from "node:os";
+import {
+  createWindowBaseName,
+  createWindowPlans,
+  findDuplicates,
+  formatInvalidModelError,
+  getBinaryName,
+  getSessionPath,
+  getWorktreePath,
+  getWorktreesForSession,
+  launchModelInWindow,
+  levenshtein,
+  normalizeModels,
+  runCommand,
+  sanitizeName,
+  shellQuote,
+  suggestModels,
+  undoWorktree,
+} from "../src/core/utils";
+
+const originalBun$: typeof Bun.$ = (globalThis as any).Bun?.$;
+let mockCommandResponses: Record<
+  string,
+  { ok: boolean; stdout: string; stderr: string }
+> = {};
+let executedCommands: string[] = [];
+
+function setupMockBun$() {
+  const mockFn = mock((_strings: TemplateStringsArray, ...values: any[]) => {
+    const parts = values[0] as string[];
+    const commandSignature = parts.join(" ");
+    executedCommands.push(commandSignature);
+    return {
+      quiet: () => ({
+        nothrow: async () => {
+          const response = mockCommandResponses[commandSignature] ?? {
+            ok: true,
+            stdout: "",
+            stderr: "",
+          };
+          return {
+            exitCode: response.ok ? 0 : 1,
+            stdout: { toString: () => response.stdout },
+            stderr: { toString: () => response.stderr },
+          };
+        },
+      }),
+    };
+  });
+  (globalThis as any).Bun.$ = mockFn;
+  return mockFn;
+}
+
+function restoreOriginalBun$() {
+  (globalThis as any).Bun.$ = originalBun$;
+}
+
+describe("core utils", () => {
+  let _bunMock: ReturnType<typeof setupMockBun$>;
+
+  beforeEach(() => {
+    spyOn(os, "homedir").mockReturnValue("/mock/home");
+    _bunMock = setupMockBun$();
+    executedCommands = [];
+    mockCommandResponses = {};
+  });
+
+  afterEach(() => {
+    restoreOriginalBun$();
+  });
+
+  describe("shellQuote", () => {
+    test("normal string without special characters", () => {
+      expect(shellQuote("test")).toBe("'test'");
+    });
+    test("string with spaces", () => {
+      expect(shellQuote("test value")).toBe("'test value'");
+    });
+    test("string with single quotes", () => {
+      expect(shellQuote("test'value")).toBe("'test'\"'\"'value'");
+    });
+    test("string with multiple single quotes", () => {
+      expect(shellQuote("te's't'v'alue")).toBe(
+        "'te'\"'\"'s'\"'\"'t'\"'\"'v'\"'\"'alue'",
+      );
+    });
+    test("empty string", () => {
+      expect(shellQuote("")).toBe("''");
+    });
+  });
+
+  describe("normalizeModels", () => {
+    test("empty array", () => {
+      expect(normalizeModels([])).toEqual([]);
+    });
+    test("undefined input", () => {
+      expect(normalizeModels(undefined)).toEqual([]);
+    });
+    test("array with whitespace-only strings", () => {
+      expect(normalizeModels(["   ", "  "])).toEqual([]);
+    });
+    test("array with mixed valid models, padded models, and empty strings", () => {
+      expect(
+        normalizeModels([" openai/gpt-5.2 ", "", " anthropic/claude "]),
+      ).toEqual(["openai/gpt-5.2", "anthropic/claude"]);
+    });
+  });
+
+  describe("findDuplicates", () => {
+    test("array with no duplicates", () => {
+      expect(findDuplicates(["a", "b", "c"])).toEqual([]);
+    });
+    test("array with one duplicate pair", () => {
+      expect(findDuplicates(["a", "b", "a"])).toEqual(["a"]);
+    });
+    test("array with multiple different duplicates", () => {
+      expect(findDuplicates(["a", "b", "a", "c", "b"])).toEqual(["a", "b"]);
+    });
+    test("array with a single value repeated more than twice", () => {
+      expect(findDuplicates(["a", "a", "a"])).toEqual(["a"]);
+    });
+    test("verifying first-repeated-occurrence order", () => {
+      expect(findDuplicates(["x", "a", "b", "a", "x", "b"])).toEqual([
+        "a",
+        "x",
+        "b",
+      ]);
+    });
+  });
+
+  describe("createWindowBaseName", () => {
+    test("normal model name without slashes", () => {
+      expect(createWindowBaseName("gpt-5-2")).toBe("gpt-5-2");
+    });
+    test("model with slashes", () => {
+      expect(createWindowBaseName("vendor/namespace/model")).toBe("model");
+    });
+    test("model exceeding WINDOW_NAME_LIMIT", () => {
+      const longName = "a".repeat(30);
+      expect(createWindowBaseName(longName)).toBe("aaaaaaaaaaaaaaaaaaaaaaaa");
+    });
+    test("model with special characters", () => {
+      expect(createWindowBaseName("OpenAI/GPT_4.0!")).toBe("gpt-4-0");
+    });
+    test("model made entirely of special characters", () => {
+      expect(createWindowBaseName("!@#$%^&*()")).toBe("model");
+    });
+  });
+
+  describe("createWindowPlans", () => {
+    test("single model", () => {
+      expect(createWindowPlans(["openai/gpt-5-2"])).toEqual([
+        { model: "openai/gpt-5-2", windowName: "gpt-5-2" },
+      ]);
+    });
+    test("two models with the same base name", () => {
+      expect(
+        createWindowPlans(["openai/gpt-5-2", "anthropic/gpt-5-2"]),
+      ).toEqual([
+        { model: "openai/gpt-5-2", windowName: "gpt-5-2" },
+        { model: "anthropic/gpt-5-2", windowName: "gpt-5-2-2" },
+      ]);
+    });
+    test("multiple collisions", () => {
+      const result = createWindowPlans(["a", "b", "c", "a", "b", "a"]);
+      expect(result[0]?.windowName).toBe("a");
+      expect(result[3]?.windowName).toBe("a-2");
+      expect(result[5]?.windowName).toBe("a-3");
+    });
+    test("truncation to accommodate suffix", () => {
+      const longBase = "a".repeat(23);
+      const result = createWindowPlans([longBase, "b"]);
+      expect(result[1]?.windowName.length).toBeLessThanOrEqual(24);
+    });
+  });
+
+  describe("levenshtein", () => {
+    test("identical strings", () => {
+      expect(levenshtein("test", "test")).toBe(0);
+    });
+    test("one substitution", () => {
+      expect(levenshtein("test", "tent")).toBe(1);
+    });
+    test("one insertion", () => {
+      expect(levenshtein("test", "tests")).toBe(1);
+    });
+    test("one deletion", () => {
+      expect(levenshtein("tests", "test")).toBe(1);
+    });
+    test("completely different strings", () => {
+      expect(levenshtein("abc", "xyz")).toBe(3);
+    });
+    test("one empty string", () => {
+      expect(levenshtein("", "test")).toBe(4);
+    });
+    test("both empty strings", () => {
+      expect(levenshtein("", "")).toBe(0);
+    });
+  });
+
+  describe("suggestModels", () => {
+    test("exact match", () => {
+      const result = suggestModels("gpt-5.2", ["gpt-5.2", "gpt-5.2-mini"]);
+      expect(result[0]).toBe("gpt-5.2");
+    });
+    test("fuzzy match/typo", () => {
+      expect(suggestModels("gpt5.4", ["gpt-5.4"])).toEqual(["gpt-5.4"]);
+    });
+    test("fuzzy match with contains boost", () => {
+      const suggestions = suggestModels("gpt4o", ["gpt-5.2", "gpt-5.2-mini"]);
+      expect(suggestions[0]).toBe("gpt-5.2");
+    });
+    test("maximum of 3 suggestions", () => {
+      const allowlist = [
+        "gpt-5.2",
+        "gpt-5.2-mini",
+        "gpt-5.2-pro",
+        "gpt-5.2-ultra",
+      ];
+      expect(suggestModels("gpt4o", allowlist).length).toBe(3);
+    });
+    test("sorting logic", () => {
+      const suggestions = suggestModels("abc", ["abc", "abd", "abe"]);
+      expect(suggestions).toEqual(["abc", "abd", "abe"]);
+    });
+  });
+
+  describe("formatInvalidModelError", () => {
+    test("single invalid model with available suggestions", () => {
+      const error = formatInvalidModelError(["gpt5.4"], ["gpt-5.4", "gpt-5.2"]);
+      expect(error).toContain("Model name 'gpt5.4' not found");
+      expect(error).toContain("Did you mean");
+    });
+    test("single invalid model without close matches", () => {
+      const error = formatInvalidModelError(["xyz"], ["abc", "def"]);
+      expect(error).toContain("Model name 'xyz' not found");
+      expect(error).toContain("Did you mean");
+    });
+    test("multiple invalid models", () => {
+      const error = formatInvalidModelError(["xyz", "abc"], ["def"]);
+      expect(error).toContain("Model names not found");
+      expect(error).toContain("'xyz'");
+      expect(error).toContain("'abc'");
+    });
+  });
+
+  describe("sanitizeName", () => {
+    test("normal alphanumeric name", () => {
+      expect(sanitizeName("test-session")).toBe("test-session");
+    });
+    test("name with spaces and special chars", () => {
+      expect(sanitizeName("test session!")).toBe("test-session");
+    });
+    test("name with consecutive hyphens", () => {
+      expect(sanitizeName("test--session")).toBe("test-session");
+    });
+    test("name with leading/trailing hyphens", () => {
+      expect(sanitizeName("-test-session-")).toBe("test-session");
+    });
+  });
+
+  describe("runCommand", () => {
+    test("returns ok true for successful command", async () => {
+      mockCommandResponses["echo hello"] = {
+        ok: true,
+        stdout: "hello",
+        stderr: "",
+      };
+      const result = await runCommand(["echo", "hello"]);
+      expect(result.ok).toBe(true);
+      expect(result.stdout).toBe("hello");
+      expect(result.stderr).toBe("");
+    });
+    test("returns ok false for failed command", async () => {
+      mockCommandResponses.false = {
+        ok: false,
+        stdout: "",
+        stderr: "error",
+      };
+      const result = await runCommand(["false"]);
+      expect(result.ok).toBe(false);
+      expect(result.stderr).toBe("error");
+    });
+  });
+
+  describe("getWorktreePath", () => {
+    test("returns correct worktree path", () => {
+      spyOn(os, "homedir").mockReturnValue("/home/user");
+      const result = getWorktreePath("my-session", "gpt-5.2");
+      expect(result).toBe(
+        "/home/user/.local/share/opencode/multi-model/my-session/gpt-5.2",
+      );
+    });
+    test("handles nested session names", () => {
+      spyOn(os, "homedir").mockReturnValue("/home/user");
+      const result = getWorktreePath("parent/child", "window");
+      expect(result).toBe(
+        "/home/user/.local/share/opencode/multi-model/parent/child/window",
+      );
+    });
+  });
+
+  describe("getSessionPath", () => {
+    test("returns correct session path", () => {
+      spyOn(os, "homedir").mockReturnValue("/home/user");
+      const result = getSessionPath("my-session");
+      expect(result).toBe(
+        "/home/user/.local/share/opencode/multi-model/my-session",
+      );
+    });
+  });
+
+  describe("undoWorktree", () => {
+    test("returns empty array on success", async () => {
+      mockCommandResponses["git worktree remove -f /path/to/worktree"] = {
+        ok: true,
+        stdout: "",
+        stderr: "",
+      };
+      mockCommandResponses["git branch -D opencode/session/window"] = {
+        ok: true,
+        stdout: "",
+        stderr: "",
+      };
+
+      const errors = await undoWorktree(
+        "/path/to/worktree",
+        "opencode/session/window",
+      );
+      expect(errors).toEqual([]);
+    });
+    test("returns error when worktree remove fails", async () => {
+      mockCommandResponses["git worktree remove -f /path/to/worktree"] = {
+        ok: false,
+        stdout: "",
+        stderr: "remove failed",
+      };
+      mockCommandResponses["git branch -D opencode/session/window"] = {
+        ok: true,
+        stdout: "",
+        stderr: "",
+      };
+
+      const errors = await undoWorktree(
+        "/path/to/worktree",
+        "opencode/session/window",
+      );
+      expect(errors.length).toBe(1);
+      expect(errors[0]).toContain("Failed to remove worktree");
+    });
+    test("returns error when branch delete fails", async () => {
+      mockCommandResponses["git worktree remove -f /path/to/worktree"] = {
+        ok: true,
+        stdout: "",
+        stderr: "",
+      };
+      mockCommandResponses["git branch -D opencode/session/window"] = {
+        ok: false,
+        stdout: "",
+        stderr: "branch delete failed",
+      };
+
+      const errors = await undoWorktree(
+        "/path/to/worktree",
+        "opencode/session/window",
+      );
+      expect(errors.length).toBe(1);
+      expect(errors[0]).toContain("Failed to delete branch");
+    });
+    test("returns both errors when both operations fail", async () => {
+      mockCommandResponses["git worktree remove -f /path/to/worktree"] = {
+        ok: false,
+        stdout: "",
+        stderr: "remove failed",
+      };
+      mockCommandResponses["git branch -D opencode/session/window"] = {
+        ok: false,
+        stdout: "",
+        stderr: "branch delete failed",
+      };
+
+      const errors = await undoWorktree(
+        "/path/to/worktree",
+        "opencode/session/window",
+      );
+      expect(errors.length).toBe(2);
+    });
+  });
+
+  describe("launchModelInWindow", () => {
+    test("sends correct tmux command", async () => {
+      mockCommandResponses[
+        "tmux send-keys -t session:window opencode --model 'openai/gpt-5.2' C-m"
+      ] = { ok: true, stdout: "", stderr: "" };
+
+      const result = await launchModelInWindow("session", {
+        model: "openai/gpt-5.2",
+        windowName: "window",
+      });
+      expect(result.ok).toBe(true);
+      expect(executedCommands).toContain(
+        "tmux send-keys -t session:window opencode --model 'openai/gpt-5.2' C-m",
+      );
+    });
+    test("uses custom binary name", async () => {
+      mockCommandResponses[
+        "tmux send-keys -t session:window kilo --model 'openai/gpt-5.2' C-m"
+      ] = { ok: true, stdout: "", stderr: "" };
+
+      const result = await launchModelInWindow(
+        "session",
+        { model: "openai/gpt-5.2", windowName: "window" },
+        "kilo",
+      );
+      expect(result.ok).toBe(true);
+      expect(executedCommands).toContain(
+        "tmux send-keys -t session:window kilo --model 'openai/gpt-5.2' C-m",
+      );
+    });
+  });
+
+  describe("getWorktreesForSession", () => {
+    test("returns session-specific worktrees", async () => {
+      spyOn(os, "homedir").mockReturnValue("/home/user");
+      mockCommandResponses["git worktree list --porcelain"] = {
+        ok: true,
+        stdout:
+          "worktree /home/user/.local/share/opencode/multi-model/my-session/gpt-5.2\nbranch refs/heads/opencode/my-session/gpt-5.2\n\nworktree /home/user/other-repo\nbranch refs/heads/main",
+        stderr: "",
+      };
+
+      const worktrees = await getWorktreesForSession("my-session");
+      expect(worktrees.length).toBe(1);
+      expect(worktrees[0]?.path).toBe(
+        "/home/user/.local/share/opencode/multi-model/my-session/gpt-5.2",
+      );
+      expect(worktrees[0]?.branch).toBe("opencode/my-session/gpt-5.2");
+    });
+    test("sanitizes session name when filtering worktrees", async () => {
+      spyOn(os, "homedir").mockReturnValue("/home/user");
+      mockCommandResponses["git worktree list --porcelain"] = {
+        ok: true,
+        stdout:
+          "worktree /home/user/.local/share/opencode/multi-model/my-session/gpt-5.2\nbranch refs/heads/opencode/my-session/gpt-5.2",
+        stderr: "",
+      };
+
+      const worktrees = await getWorktreesForSession("my session!");
+      expect(worktrees.length).toBe(1);
+      expect(worktrees[0]?.path).toBe(
+        "/home/user/.local/share/opencode/multi-model/my-session/gpt-5.2",
+      );
+    });
+    test("returns empty array when no matching worktrees", async () => {
+      spyOn(os, "homedir").mockReturnValue("/home/user");
+      mockCommandResponses["git worktree list --porcelain"] = {
+        ok: true,
+        stdout: "worktree /home/user/other-repo\nbranch refs/heads/main",
+        stderr: "",
+      };
+
+      const worktrees = await getWorktreesForSession("my-session");
+      expect(worktrees).toEqual([]);
+    });
+  });
+
+  describe("getBinaryName", () => {
+    test("returns default 'opencode' when env var not set", () => {
+      delete process.env.OPENCODE_MULTI_MODEL_BINARY;
+      expect(getBinaryName()).toBe("opencode");
+    });
+    test("returns env var value when set", () => {
+      process.env.OPENCODE_MULTI_MODEL_BINARY = "kilo";
+      expect(getBinaryName()).toBe("kilo");
+      delete process.env.OPENCODE_MULTI_MODEL_BINARY;
+    });
+  });
+});