LSP servers (language intelligence)

Language servers give Claude Code automatic diagnostics (type errors, missing imports, lint) after each edit, plus code navigation (definitions, references, hover). It's background tooling — no model-facing tool calls and no context-token cost — so it makes edits more correct without making sessions more expensive.

Why it's a separate, opt-in plugin

LSP requires the language-server binaries installed on your PATH. Bundling them into the main core plugin would force-start servers that some teammates don't have. So they live in a companion plugin you enable deliberately:

/plugin install core-lsp@compass

Verified inventory (claude plugin details core-lsp@compass): 4 LSP servers — gopls, rust-analyzer, typescript, pyright.

Prerequisites (install the servers you need)

go install golang.org/x/tools/gopls@latest                 # Go
rustup component add rust-analyzer                          # Rust
npm i -g typescript-language-server typescript              # TypeScript
npm i -g pyright                                            # Python (pyright-langserver)

A server with no binary simply doesn't start for that language — harmless, but that's why this is opt-in rather than default.

What's configured (plugins/core-lsp/.lsp.json)

Server	Command	Files
gopls	gopls serve	.go
rust-analyzer	rust-analyzer	.rs
typescript	typescript-language-server --stdio	.ts .tsx .js .jsx
pyright	pyright-langserver --stdio	.py

Add a server by adding an entry: "<name>": { "command", "args", "extensionToLanguage" }.

Honest note on Codex parity

LSP is Claude-only. Codex (~/.codex/config.toml) has no native LSP configuration section — only [mcp_servers.*]. So unlike MCP, there's no true LSP parity to ship. (A community codex-lsp MCP server can expose LSP-over-MCP, but it's unverified here, so we don't wire it.) The MCP parity layer (docs/04-mcp.md) remains the cross-tool story; LSP augments Claude specifically.