Ty

Python type checking with ty

Inspect [tool.ty] or ty.toml, supported Python versions, dependencies, and existing check coverage. In a project with ty declared, run uv run ty check; use uv run --frozen ty check for locked verification from the manifest directory. Read uv for environment selection. Preserve another chosen checker unless migration is within scope.

• Check the maintained application, tests, scripts, and templates that can execute as Python. Confirm configured include/exclude paths actually cover the changed files. Treat generated snapshots, vendored code, and deliberate negative fixtures according to their existing contract.
• Set the target to the project's supported Python minimum. Do not raise it merely to remove diagnostics. Resolve imports through the real project environment rather than a broad ignore.
• Repair type errors by validating external data and using truthful, narrow types. Do not add casts, Any, or ignore comments just to hide errors. Add an ignore only when the user explicitly requests it; use a rule-specific ty: ignore[...] and retain a concrete reason.
• Check targeted files during repair, then run the full configured type check. Verify runtime behavior with the affected tests; static success alone does not establish correctness.

Use ruff for lint and format. Preserve existing planning, permission, and projectctl verification ownership. This Kiro skill does not configure a language server or install the upstream Claude plugin; an LSP setup is a separate requested task.

Reference: ty documentation.