protolint

What is protolint?

protolint is a pluggable linting and fixing utility for Protocol Buffer files (proto2 and proto3). It runs without a compiler, enforces the official style guide, and can automatically fix violations. protolint now includes a built-in MCP (Model Context Protocol) server, enabling AI models to lint and fix proto files directly.

How to use protolint?

Install protolint via Homebrew, pre‑built GitHub releases, Docker, source, npm, or pypi. To start the MCP server, run protolint --mcp from the command line. For standard linting, use protolint lint [files or directories]. Configuration is optional and can be provided via YAML files; most projects work out of the box.

Key features of protolint

• Pluggable custom lint rules via plugins
• Automatic fixing of official style guide violations
• Comment‑based rule disabling to maintain compatibility
• Runs fast without requiring a Protocol Buffer compiler
• MCP server for direct interaction with AI models
• Integrated with editors, CI systems, and GitHub Actions

Use cases of protolint

• Enforce style guide consistency across large proto‑based projects
• Automatically fix style violations in pre‑commit hooks or CI pipelines
• Integrate linting into IDEs like VS Code, JetBrains, and Vim
• Use AI assistants (via MCP) to lint and fix proto files on demand
• Run linting in Docker for reproducible builds in any environment

FAQ from protolint

What is protolint and how does it differ from other proto linters?

protolint is a standalone linter that does not require the Protocol Buffer compiler. It focuses on style guide compliance, includes an auto‑fixer, and supports custom rules via plugins. It also offers an MCP server for AI tool integration.

How do I install protolint?

You can install it using Homebrew, download a pre‑built binary from GitHub Releases, use the Docker image yoheimuta/protolint, build from source with Go, or install via npm (npm install protolint) or pypi (protolint-bin).

Does protolint support MCP servers?

Yes. Run protolint --mcp to start the MCP server. This allows MCP clients such as Claude Desktop to lint and fix Protocol Buffer files.

Can protolint automatically fix style violations?

Yes, the -fix flag automatically corrects many style guide violations. The -auto_disable option can also insert disable comments for violations that cannot be auto‑fixed, preserving existing compatible code.

Is protolint available as a Docker image?

Yes. The official Docker image is yoheimuta/protolint. You can mount your workspace and run linting with a command like docker run --volume "$(pwd):/workspace" --workdir /workspace yoheimuta/protolint lint <target>.