x/pkgsite: remote MCP support

[H0llyW00dzZ]

What is the URL of the page with the issue?

https://pkg.go.dev/

What is your user agent?

Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36

Screenshot

No response

What did you do?

If possible, it would be beneficial to implement MCP (Model Context Protocol) support similar to gopls for pkg.go.dev. This would make integration with AI tools significantly easier, especially for learning and reading Go documentation through https://pkg.go.dev/.

What did you see happen?

Currently, pkg.go.dev does not expose an MCP server interface. While the website provides excellent documentation through its web interface, there is no programmatic way for AI tools to:

• Query package information via MCP protocol
• Retrieve documentation in a structured format for AI consumption
• Access code examples and API references through standardized MCP tools
• Integrate with AI coding assistants like those supporting gopls MCP

This limitation means developers using AI-assisted tools must manually copy documentation or rely on potentially outdated information embedded in AI training data.

What did you expect to see?

An MCP server implementation for pkg.go.dev that provides:

Core MCP Tools:

1. search_packages - Search for Go packages by name or description

   {
     "name": "search_packages",
     "description": "Search for Go packages on pkg.go.dev",
     "inputSchema": {
       "query": "string",
       "limit": "number (optional)"
     }
   }

2. get_package_doc - Retrieve complete package documentation

   {
     "name": "get_package_doc",
     "description": "Get documentation for a specific package",
     "inputSchema": {
       "import_path": "string",
       "version": "string (optional)"
     }
   }

3. get_symbol_doc - Get documentation for specific functions, types, or methods

   {
     "name": "get_symbol_doc",
     "description": "Get documentation for a specific symbol",
     "inputSchema": {
       "import_path": "string",
       "symbol_name": "string"
     }
   }

4. get_examples - Retrieve code examples for packages or symbols

   {
     "name": "get_examples",
     "description": "Get code examples from package documentation",
     "inputSchema": {
       "import_path": "string",
       "symbol_name": "string (optional)"
     }
   }

5. list_versions - List available versions of a package

   {
     "name": "list_versions",
     "description": "List all available versions of a package",
     "inputSchema": {
       "import_path": "string"
     }
   }

Configuration Example:

{
  "mcp": {
    "pkgsite": {
      "type": "remote",
      "url": "https://pkg.go.dev/mcp",
      "enabled": true,
      "options": {
        "cache_duration": "24h",
        "max_results": 50
      }
    }
  }
}

Benefits:

• Enhanced AI Integration: AI coding assistants can provide accurate, up-to-date Go documentation
• Improved Developer Experience: Seamless documentation lookup without leaving the development environment
• Standardized Access: Consistent interface for accessing Go documentation across different AI tools
• Learning Acceleration: AI tutors can reference official documentation when teaching Go
• Version-aware Assistance: AI tools can provide version-specific documentation and migration guidance

Implementation Considerations:

• Follow the MCP specification similar to gopls implementation
• Implement rate limiting to prevent abuse
• Support both SSE (Server-Sent Events) and stdio transports
• Provide caching mechanisms for frequently accessed documentation
• Maintain compatibility with existing pkg.go.dev infrastructure

---

Related Work

• gopls MCP: https://github.com/golang/tools/tree/master/gopls (reference implementation)
• MCP Specification: https://modelcontextprotocol.io/

This feature would position pkg.go.dev as a leader in AI-assisted development tooling and significantly improve the Go learning and development experience.

[findleyr]

This is not a duplicate of #36785. An MCP server for pkg.go.dev has different implications than an ordinary API. Though I do think it would be odd to have one and not the other (and an MCP server could be used as an API).

And yes, this is something we've been thinking about as well.

[H0llyW00dzZ]

This is not a duplicate of #36785. An MCP server for pkg.go.dev has different implications than an ordinary API. Though I do think it would be odd to have one and not the other (and an MCP server could be used as an API).

And yes, this is something we've been thinking about as well.

@findleyr, That's great! This would make Go the first language to have official MCP support from the core team. Other languages don't have implementations officially supported by their respective teams.

[gabyhelp]

Related Issues

• x/tools/gopls: expose an off-by-default MCP server from gopls #73580 (closed)
• x/pkgsite: feature request golang packages registry api #69514 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[prattmic]

cc @golang/pkgsite

[reneleonhardt]

It seems very unlikely that the maintainers would discard an API for 5 years which would be useful to everyone but then chose to implement a MCP server instead which could only be used by AI users...

[H0llyW00dzZ]

It seems very unlikely that the maintainers would discard an API for 5 years which would be useful to everyone but then chose to implement a MCP server instead which could only be used by AI users...

@reneleonhardt current feature request seems fair, and its not just AI users either.

[reneleonhardt]

I'm not against this feature request, just wondering how users could query the MCP server without a MCP client if no alternative API would exist?

The API that has been requested 5 years ago would be similar to it's predecessor godoc.org and allow consuming universally per REST or GraphQL with countless clients and frameworks.