refactor(agent): Put agent_tools in different files

agent_tools/section_retriever.ts

@@ -0,0 +1,75 @@
+/**
+ * Section chunk retriever tool.
+ * Retrieves all text chunks from a specific specification section by sectionid.
+ */
+
+import type { Table } from "@lancedb/lancedb";
+import { DynamicStructuredTool } from "@langchain/core/tools";
+import { z } from "zod";
+
+const sectionRetrieverSchema = z.object({
+  sectionId: z
+    .string()
+    .describe("The section ID (e.g., 'sec-if-statement') to fetch chunks for"),
+});
+
+/**
+ * Creates the section retriever tool.
+ * @param table - LanceDB table containing spec vectors
+ */
+export function createSectionRetrieverTool(table: Table) {
+  return new DynamicStructuredTool({
+    name: "fetch_section_chunks",
+    description:
+      "Retrieves all text chunks from a specific specification section by sectionid. " +
+      "Supports recursive fetching - if a section has children, it will fetch all descendants. " +
+      "Use this to get complete content when you see 'Subsection available' or 'partial section' references.",
+    schema: sectionRetrieverSchema,
+    func: async ({ sectionId }) => {
+      const allDocs: string[] = [];
+      const queue: string[] = [sectionId];
+      const visited = new Set<string>();
+
+      while (queue.length > 0) {
+        const currentId = queue.shift()!;
+        if (visited.has(currentId)) continue;
+        visited.add(currentId);
+
+        const results = await table
+          .query()
+          .where(`sectionid = '${currentId}'`)
+          .limit(100)
+          .toArray();
+
+        // Sort by partIndex to maintain order (nulls last for single-part sections)
+        const sortedResults = results.sort((a: unknown, b: unknown) => {
+          const aIndex = (a as { partIndex?: number }).partIndex ?? Infinity;
+          const bIndex = (b as { partIndex?: number }).partIndex ?? Infinity;
+          return aIndex - bIndex;
+        });
+
+        for (const result of sortedResults) {
+          const typedResult = result as {
+            text?: string;
+            childrensectionids?: string[];
+            sectiontitle?: string;
+          };
+
+          if (typedResult.text) {
+            allDocs.push(typedResult.text);
+          }
+
+          // Add children to queue for recursive fetching
+          if (
+            typedResult.childrensectionids &&
+            Array.isArray(typedResult.childrensectionids)
+          ) {
+            queue.push(...typedResult.childrensectionids);
+          }
+        }
+      }
+
+      return allDocs.join("\n\n---\n\n");
+    },
+  });
+}