Ask262

MCP server for exploring the ECMAScript specification and its implementation in engine262.

Features

• Vector search ECMAScript specification sections using semantic queries
• Execute JavaScript in engine262 and capture which spec sections are hit
• Knowledge graph mapping spec sections to implementation functions
• 1-second timeout on code execution for safety

Prerequisites

• Bun: Version 1.0.0 or higher (install)
• Ollama: Installed locally with qwen3-embedding:0.6b model pulled (ollama pull qwen3-embedding:0.6b)

Environment Variables

• OLLAMA_HOST (optional): Ollama server URL. Defaults to http://localhost:11434

Installation

# Install globally with bun
bun install -g ask262

# Or run directly without installing
bunx ask262

# Or clone and install
git clone https://github.com/bendtherules/ask262
cd ask262
bun install

MCP Configuration

Add to your MCP client configuration using bunx (no installation required):

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "ask262": {
      "command": "bunx",
      "args": ["ask262"]
    }
  }
}

OpenCode (.opencode/mcp.json):

{
  "servers": {
    "ask262": {
      "command": "bunx",
      "args": ["ask262"]
    }
  }
}

Available Tools

Tool	Description
ask262_search_spec_sections	Vector search ECMAScript spec for relevant sections
ask262_get_section_content	Retrieve full content from a spec section
ask262_evaluate_in_engine262	Execute JS in engine262 and capture spec section marks

Testing

# Run MCP server tests
bun run test-mcp-server

# Test evaluate tool with timeout
bun run test-evaluate-timeout

# Test search functionality
bun run test-search-spec-sections

Development

For development or using a custom ECMAScript specification:

1. Clone and setup:

   git clone https://github.com/bendtherules/ask262
   cd ask262
   bun install
   

2. Ensure spec is present:

   • ./spec-built/multipage/ - ECMAScript spec HTML files

3. Build knowledge graph (if using custom spec):

   bun run build
   

License

ISC