Support LSP servers configured in plugins/marketplace

[neubig]

Summary

Add runtime support for Language Server Protocol (LSP) servers that are configured in plugin marketplace entries. This enables plugins to provide enhanced code intelligence features like go-to-definition, find references, diagnostics, and completions for specific languages.

Context

The Anthropic Claude Code plugin marketplace schema includes lspServers configuration in plugin entries. For example, from anthropics/claude-plugins-official:

{
  "name": "typescript-lsp",
  "description": "TypeScript/JavaScript language server for enhanced code intelligence",
  "strict": false,
  "lspServers": {
    "typescript": {
      "command": "typescript-language-server",
      "args": ["--stdio"],
      "extensionToLanguage": {
        ".ts": "typescript",
        ".tsx": "typescriptreact"
      }
    }
  }
}

The official Anthropic marketplace includes LSP plugins for: TypeScript, Python (Pyright), Go, Rust, C/C++, PHP, Swift, Kotlin, C#, Java, and Lua.

Current State

The Marketplace datamodel in openhands.sdk.plugin now supports parsing lspServers from marketplace.json files (PR #1744), but there is no runtime support for actually starting and communicating with LSP servers.

Proposed Work

1. LSP Client: Implement client to spawn and communicate with language servers via stdio
2. Server Lifecycle: Start/stop LSP servers based on file types being edited
3. Tool Exposure: Optionally expose LSP capabilities as agent tools
4. File Routing: Use extensionToLanguage config to route requests to appropriate servers

Non-Goals

This is NOT about reimplementing all code editing to use LSP (that was the scope of OpenHands/OpenHands#1934). This is specifically about supporting the LSP server configurations that plugins/marketplaces can provide.

Related

• Marketplace datamodel PR: Add Marketplace datamodel for marketplace.json support #1744
• Claude Code LSP plugins: https://github.com/anthropics/claude-plugins-official
• Original broader LSP discussion: Use Language Server Protocol (LSP) to re-implement all code editing OpenHands#1934 (closed)