pi-lsp

Standalone pi extension that adds a code_symbols tool backed by project-configured Language Server Protocol processes.

Status

Current implementation:

• Spawns and manages one LSP subprocess per (server id, workspace root) pair
• Supports multiple configured servers in the same workspace
• Routes requests by serverId, language, and filePath
• Cleans up all spawned processes on pi shutdown and extension reload
• Exposes search, definitions, and references through the code_symbols tool
• Returns optional source snippets using the LSP-reported range

Not implemented yet:

• Tree-sitter-based expansion from a symbol range to the enclosing syntax node
• Automatic installation or discovery of language servers
• Rich disambiguation UI when multiple document symbols match the same pattern

Install

cd /path/to/pi-lsp
bun install

Load it in pi:

pi --extension /path/to/pi-lsp/src/index.ts

Or point pi at the package directory if you use it as a project extension source.

Configuration

Create .pi/lsp.json in the target workspace:

{
  "defaultLimit": 25,
  "maxLimit": 100,
  "servers": [
    {
      "id": "ts",
      "name": "TypeScript",
      "languages": ["typescript", "javascript"],
      "fileGlobs": ["src/*.ts", "src/*.tsx", "test/*.ts"],
      "rootMarkers": ["package.json", "tsconfig.json"],
      "command": {
        "command": "vtsls",
        "args": ["--stdio"]
      }
    },
    {
      "id": "py",
      "name": "ty",
      "languages": ["python"],
      "fileGlobs": ["pkg/*.py", "tests/*.py"],
      "rootMarkers": ["pyproject.toml", "setup.py"],
      "command": {
        "command": "ty",
        "args": ["--stdio"]
      }
    },
    {
      "id": "rust",
      "name": "rust-analyzer",
      "languages": ["rust"],
      "fileGlobs": ["src/*.rs", "tests/*.rs", "examples/*.rs"],
      "rootMarkers": ["Cargo.toml"],
      "command": {
        "command": "rust-analyzer"
      }
    }
  ]
}

Fields

• servers: required, non-empty array
• id: stable server identifier
• languages: optional language filter used during routing
• fileGlobs: optional minimatch globs evaluated relative to the workspace cwd
• rootMarkers: optional files/directories used to compute the server root
• command.command: executable to spawn
• command.args: optional argument array
• command.env: optional environment variables
• initializationOptions: optional LSP initialization payload
• trace: optional LSP trace level
• treeSitterLanguage: reserved for upcoming tree-sitter source expansion

Tool API

The extension registers one tool:

• code_symbols

Parameters:

• action: "search" | "definitions" | "references"
• name: symbol name or wildcard pattern
• filePath: optional for search, required for definitions and references
• language: optional language override
• serverId: optional explicit server override
• includeSource: include source snippets in results
• limit: result cap

Examples:

Use code_symbols to search for "run*"
Use code_symbols to find definitions of "runTask" in src/app.ts
Use code_symbols to find references of "make_widget" in pkg/tool.py

Development

bun run check
bun test

The tests use a fake stdio LSP server and verify:

• server routing across multiple configured servers
• workspace symbol search
• document symbol + definition flow
• references flow
• shutdown cleanup