---
slug: "pi-diet-lsp"
source_type: "readme"
source_url: "https://cdn.jsdelivr.net/gh/ProbabilityEngineer/pi-diet-lsp@main/README.md"
repo: "https://github.com/ProbabilityEngineer/pi-diet-lsp"
source_file: "README.md"
branch: "main"
---
# pi-diet-lsp

> One of my diet context engineering and workflow extensions. Add pi-diet-LSP, pi-diet-Ripgrep, pi-repo-move and others from [npm](https://www.npmjs.com/~probabilityengineer).

On-demand LSP code-intelligence tools for Pi without automatic diagnostics or context injection.

`pi-diet-lsp` gives Pi agents focused, model-visible Language Server Protocol tools for definitions, references, symbols, hover/type information, and diagnostics. It keeps the surface compact and explicit: no automatic diagnostics pipeline, no context injection, no read guard, no skills, and no session-start bootstrap. Agents call the tools when precise code intelligence is useful.

This is intentionally different from automatic LSP feedback extensions: `pi-diet-lsp` favors low prompt overhead and explicit tool calls over continuously appending diagnostics to every edit.

## Tools

- `lsp_definition` — jump to definition at a 1-based file position
- `lsp_references` — find references at a 1-based file position
- `lsp_symbols` — document symbols for a file, or workspace symbols by query
- `lsp_hover` — show hover/type info at a 1-based file position
- `lsp_diagnostics` — open a file in LSP and return current diagnostics

`lsp_symbols` has two modes:

```json
{ "filePath": "src/index.ts", "query": "optional-filter" }
{ "query": "SymbolName" }
```

With `filePath`, it returns document symbols. Without `filePath`, it uses LSP workspace symbol search.

Large symbol/reference results are compacted and capped to avoid runaway context growth.

## Install

From npm, after publication:

```bash
pi install npm:pi-diet-lsp
```

From GitHub:

```bash
pi install git:github.com/ProbabilityEngineer/pi-diet-lsp
```

For project-local install, add `-l`:

```bash
pi install -l git:github.com/ProbabilityEngineer/pi-diet-lsp
```

For local testing:

```bash
pi -e ./index.ts
```

## Runtime requirements

LSP tools resolve language servers from `PATH` using broader built-in defaults and first-available selection when multiple servers are supported.

Current built-in mappings include:

- TypeScript/JavaScript: `typescript-language-server --stdio`
- Vue: `vue-language-server --stdio`
- Python: `basedpyright-langserver --stdio`, fallback `pyright-langserver --stdio`
- Go: `gopls`
- Rust: `rust-analyzer`
- Swift: `sourcekit-lsp`
- C/C++: `clangd`
- C#: `csharp-ls`, fallback `omnisharp --languageserver`
- Java: `jdtls`
- Kotlin: `kotlin-language-server`
- PHP: `intelephense --stdio`, fallback `phpactor language-server`
- Ruby: `ruby-lsp`, fallback `solargraph stdio`
- Lua: `lua-language-server`
- Nix: `nixd`, fallback `nil`
- HTML: `vscode-html-language-server --stdio`
- CSS/SCSS/Less: `vscode-css-language-server --stdio`
- JSON: `vscode-json-language-server --stdio`
- YAML: `yaml-language-server --stdio`

## Configuration overrides

You can override or add language mappings with:

```text
~/.pi/agent/pi-diet-lsp/config.json
```

Example:

```json
{
  "languages": {
    "lua_override": {
      "languageId": "lua",
      "extensions": [".lua"],
      "servers": [
        { "command": "custom-lua-lsp", "args": ["--stdio"] }
      ]
    }
  }
}
```

Configured languages are checked before built-in defaults.

You can also provide per-server environment variables, which is especially useful for OmniSharp:

```json
{
  "languages": {
    "csharp_override": {
      "languageId": "csharp",
      "extensions": [".cs"],
      "servers": [
        {
          "command": "omnisharp",
          "args": ["--languageserver"],
          "env": {
            "DOTNET_ROOT": "/Users/you/.dotnet"
          }
        }
      ]
    }
  }
}
```

## C# notes and troubleshooting

- `pi-diet-lsp` prefers `csharp-ls` first, then falls back to `omnisharp`.
- The selected executable must be runnable from `PATH` in a non-interactive shell.
- For OmniSharp, `pi-diet-lsp` now auto-uses `~/.dotnet` as `DOTNET_ROOT` when present. If your setup differs, set `env.DOTNET_ROOT` in config.
- Legacy `.NET Framework` projects may still load with partial diagnostics on macOS/Linux if reference assemblies/targeting packs are unavailable.
- If a server fails to launch, tool errors now include launch details and stderr instead of only reporting an initialize timeout.

## Validation

```bash
npm run lint
npm run test:resolution
```

## Prompt overhead

`pi-diet-lsp` avoids automatic context injection. It registers compact tools and guidance, then waits for agents to call LSP tools explicitly when code intelligence is relevant.