ty-lsp

ty-lsp

A Claude Code plugin that integrates ty (Astral's Python type checker) as an LSP server, based on the official pyright-lsp plugin.

Why?

Without an LSP, Claude Code navigates your codebase by searching text, grepping for symbol names, scanning files for patterns, and hoping the matches are relevant. An LSP gives it structured understanding of your code: jump to definitions, find all references, see type information on hover, and get real-time diagnostics as it edits. This means Claude can work with your Python code the way an IDE does, following the actual structure of the code rather than guessing from string matches.

The pyright-lsp plugin does all of this too! So why ty? There a few reasons, one is that ty is written in Rust with incremental recomputation at its core, so in practice it uses less CPU and memory than Pyright, and tends to be faster at updating diagnostics after edits. See the ty benchmarks for detailed comparisons.

In practice, Claude Code's response time is dominated by LLM reasoning calls, so the raw speed difference between type checkers matters less than in other contexts. What matters more is that the LSP your agent is using is consistent with the type checker you run in CI. If you use ty in CI, this plugin means Claude sees the same view of your code as your pipeline does.

Prerequisites

Install ty globally so that it is available on your PATH. The recommended approach is with uv:

uv tool install ty

Any other method of globally installing ty should also work, such as pipx, the Astral install script, or even a global pip install ty (though that's not a great idea).

Installation

Install from the tcbegley-cc-plugins marketplace:

/plugin marketplace add tcbegley/tcbegley-cc-plugins
/plugin install ty-lsp@tcbegley-cc-plugins

Development

claude --plugin-dir /path/to/ty-cc-plugin

What it provides

• Real-time Python type checking diagnostics as Claude edits code
• Code navigation (go to definition, find references)
• Hover information with type details

Configuration

ty is configured via ty.toml or the [tool.ty] section of pyproject.toml. See the ty configuration docs for details.