vis-lang-python

Python tools for Vis: ruff formatting and lint, pytest runs and a REPL that keeps its globals between calls.

Vis knows nothing about Python. This extension does, and it runs the tools your project already uses — its ruff, its pytest, its interpreter — so what you see here matches what your CI sees.

Install

vis-agent extension install 'blockether/vis-lang-python' --global --trust

Tools

py.format_code(["src"], is_written=True)     # ruff format
py.lint_code(["src"])                        # ruff check, with rule codes
py.run_tests(["tests"], keyword="repl")      # pytest, counted from its JUnit report
py.repl_start(cwd="~/app")                   # the project's own interpreter
py.repl_eval("model = load()", cwd="~/app")  # globals live between calls
py.repl_stop(cwd="~/app")

Which interpreter runs your tests and REPL is decided per project, first match winning: uv (uv.lock or [tool.uv]), Poetry (poetry.lock), a local .venv, then python3. Ruff is taken from the project's virtualenv, then PATH, then the copy installed with this extension.

Keep files parseable

Syntax checks run automatically through edit hooks, not through a public tool. The extension compiles changed .py and .pyi files with each project's interpreter. It does not execute the code, write bytecode files or change your REPL's globals.

• A patch that would make a parseable file unparseable is refused. Nothing is written.
• After each python_execution block, the guard checks changed files again. Errors appear in session["python_syntax_errors"] until the files parse again.

The shared syntax guard selects matching files. If the interpreter is unavailable, the guard allows the edit and logs the failure.

Requirements

pytest in the project you test. Everything else is installed with the extension.

Development

vis-agent python -m pytest tests -q

Results follow the contract in vis-lang-interface.