Python

Install

Pyright is a fast, feature-rich Python language server from Microsoft.

macOS

npm install -g pyright

Or via Homebrew:

brew install pyright

Linux

npm install -g pyright

Windows

npm install -g pyright

Config

Catenary ships a built-in definition for pyright — no [lsp.server.*] config is needed. If pyright-langserver is on PATH, it works automatically.

To customise settings, add to ~/.config/catenary/config.toml:

[lsp.server.pyright-langserver.settings.python]
pythonPath = "/usr/bin/python3"

[lsp.server.pyright-langserver.settings.python.analysis]
exclude = ["**/target", "**/node_modules"]
extraPaths = []

Pyright requests configuration via workspace/configuration. Use the settings table on the [lsp.server.*] entry to provide Python interpreter paths, analysis exclusions, and other options (shown above).

Without these settings, pyright may fall back to scanning the entire workspace (including large directories like target/ or node_modules/), which can cause extremely slow initialization.

See the Pyright configuration docs for the full list of available settings.

Notes

Pyright provides type checking even for untyped code (infers types)
Works well with virtual environments — activate your venv before starting your MCP client
For Django/Flask projects, Pyright handles most patterns out of the box

Alternatives

Pylsp (python-lsp-server)

A community-maintained server with plugin support:

pip install python-lsp-server

[lsp.language.python]
servers = ["pylsp"]

No [lsp.server.pylsp] block is needed — the section key pylsp is the binary Catenary spawns; add one with path = "/abs/path" only to relocate it.

Jedi Language Server

Lightweight, uses Jedi for completions:

pip install jedi-language-server

[lsp.language.python]
servers = ["jedi-language-server"]

The section key jedi-language-server is the binary Catenary spawns, so no [lsp.server.*] block is needed — add one with path = "/abs/path" only to relocate a binary that is not on PATH.

Catenary