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This agent specializes in generating high-quality Python code with a focus on proper formatting and linting. It uses black, ruff, and mypy to ensure the code meets standard quality checks.

This streamlines the coding process by integrating and responding to these checks, resulting in reliable and consistent code output.

It cannot actually execute the code it writes, as code execution may introduce additional dependencies and potential security vulnerabilities. This makes the agent both a secure and efficient solution for code generation tasks.

You can use it to generate Python code directly, or network it with planning and execution agents.

Environment Setup​

  • Install black, ruff, and mypy: pip install -U black ruff mypy
  • Set OPENAI_API_KEY environment variable.


To use this package, you should first have the LangChain CLI installed:

pip install -U langchain-cli

To create a new LangChain project and install this as the only package, you can do:

langchain app new my-app --package python-lint

If you want to add this to an existing project, you can just run:

langchain app add python-lint

And add the following code to your file:

from python_lint import agent_executor as python_lint_agent

add_routes(app, python_lint_agent, path="/python-lint")

(Optional) Let's now configure LangSmith. LangSmith will help us trace, monitor and debug LangChain applications. LangSmith is currently in private beta, you can sign up here. If you don't have access, you can skip this section

export LANGCHAIN_API_KEY=<your-api-key>
export LANGCHAIN_PROJECT=<your-project> # if not specified, defaults to "default"

If you are inside this directory, then you can spin up a LangServe instance directly by:

langchain serve

This will start the FastAPI app with a server is running locally at http://localhost:8000

We can see all templates at We can access the playground at

We can access the template from code with:

from langserve.client import RemoteRunnable

runnable = RemoteRunnable("http://localhost:8000/python-lint")