🧠 pi-lsp — Configurable Language Server Tools for Pi

@narumitw/pi-lsp is a native Pi coding agent extension that exposes diagnostics and source-fix tools through configurable Language Server Protocol routes.

The extension is language-agnostic: servers are selected by config and file extension instead of hard-coded language families.

✨ Features

• Configure LSP servers with simple JSON keyed by server name.
• Routes diagnostics and source fixes by configured file extensions.
• Supports multiple servers for the same extension, for example ty and ruff for .py/.pyi diagnostics.
• Uses one internal LSP runner for JSON-RPC framing, subprocess lifecycle, diagnostics, code actions, and workspace edit application.
• Supports workspace roots, file limits, recursive file discovery, server overrides, and write-or-preview edits.
• Starts language servers only for tool calls, then shuts them down.
• Shows statusline activity only while LSP tools are running.

📦 Install

pi install npm:@narumitw/pi-lsp

Try this package locally from the repository root:

pi -e ./extensions/pi-lsp

⚙️ Configuration

If no config is provided, pi-lsp ships compatible defaults for Biome, ty, and Ruff.

Custom config can be supplied in one of these locations:

1. PI_LSP_CONFIG as inline JSON or a path to a JSON file
2. <workspace>/.pi/lsp.json
3. ~/.pi/agent/lsp.json

PI_LSP_CONFIG only accepts JSON or a JSON file path; JavaScript and TypeScript config files are not evaluated.

lsp.json can be a plain object keyed by server name:

{
  "ty": {
    "command": ["ty", "server"],
    "extensions": [".py", ".pyi"]
  },
  "ruff": {
    "command": ["ruff", "server"],
    "extensions": [".py", ".pyi"]
  },
  "biome": {
    "command": ["biome", "lsp-proxy"],
    "extensions": [
      ".astro",
      ".css",
      ".graphql",
      ".gql",
      ".html",
      ".js",
      ".jsx",
      ".json",
      ".jsonc",
      ".ts",
      ".tsx",
      ".vue"
    ]
  }
}

Use servers when you need global pi-lsp options such as timeout:

{
  "timeout": 30000,
  "servers": {
    "ty": {
      "command": ["ty", "server"],
      "extensions": [".py", ".pyi"],
      "env": {
        "LSP_LOG": "debug"
      },
      "initialization": {
        "settings": {}
      }
    }
  }
}

Each server entry supports:

• command: argv array used to start the LSP server.
• extensions: file extensions that should route to this server.
• env: extra environment variables for the LSP server process.
• initialization: LSP initialization options and workspace configuration values.

Global options:

• timeout: request timeout in milliseconds. Defaults to 20000.

pi-lsp infers languageId from common extensions and falls back to the extension without the leading dot.

Per-server command overrides still use the normalized server name:

PI_TY_LSP_COMMAND="uvx ty server" \
PI_RUFF_LSP_COMMAND="uvx ruff server" \
pi -e ./extensions/pi-lsp

⚠️ Tool changes

lsp_format is no longer provided. pi-lsp now focuses on LSP diagnostics and source code actions:

• lsp_diagnostics
• lsp_fix

Use project formatters or shell commands for formatting workflows.

🛠️ Pi tools

lsp_diagnostics

Run diagnostics through configured servers.

Parameters:

• paths?: files or directories to check. Defaults to the workspace root.
• root?: workspace root. Defaults to cwd.
• limit?: maximum files to open per selected server.
• server?: configured server name, or an array of names. Defaults to all matching servers.

lsp_fix

Apply source fixes or import organization through a configured server that matches its extension. If multiple servers match, pass server explicitly.

Parameters:

• path: file to fix.
• root?: workspace root. Defaults to cwd.
• kind?: source action kind. Defaults to source.fixAll.
• write?: write fixed text back to the file. Defaults to false.
• server?: optional configured server name.

💬 Command

/lsp

Shows configured LSP commands and whether each command is available on PATH.

🗂️ Package layout

extensions/pi-lsp/
├── src/
│   ├── adapters.ts
│   ├── command.ts
│   ├── files.ts
│   ├── lsp-client.ts
│   ├── pi-lsp.ts
│   ├── routes.ts
│   ├── runner.ts
│   ├── text-edits.ts
│   └── types.ts
├── README.md
├── LICENSE
├── tsconfig.json
└── package.json

📄 License

MIT. See LICENSE.