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How to contribute

We would love to accept your patches and contributions to this project. This document includes:

We're looking forward to seeing your contributions!

Before you begin​

Sign our Contributor License Agreement​

Contributions to this project must be accompanied by a Contributor License Agreement (CLA). You (or your employer) retain the copyright to your contribution; this simply gives us permission to use and redistribute your contributions as part of the project.

If you or your current employer have already signed the Google CLA (even if it was for a different project), you probably don't need to do it again.

Visit https://cla.developers.google.com/ to see your current agreements or to sign a new one.

Review our Community Guidelines​

This project follows Google's Open Source Community Guidelines.

Code contribution process​

Get started​

The process for contributing code is as follows:

  1. Find an issue that you want to work on.
  2. Fork the repository and create a new branch.
  3. Make your changes in the packages/ directory.
  4. Ensure all checks pass by running npm run preflight.
  5. Open a pull request with your changes.

Code reviews​

All submissions, including submissions by project members, require review. We use GitHub pull requests for this purpose.

If your pull request involves changes to packages/cli (the frontend), we recommend running our automated frontend review tool. Note: This tool is currently experimental. It helps detect common React anti-patterns, testing issues, and other frontend-specific best practices that are easy to miss.

To run the review tool, enter the following command from within Gemini CLI:

/review-frontend <PR_NUMBER>

Replace <PR_NUMBER> with your pull request number. Authors are encouraged to run this on their own PRs for self-review, and reviewers should use it to augment their manual review process.

Self assigning issues​

To assign an issue to yourself, simply add a comment with the text /assign. The comment must contain only that text and nothing else. This command will assign the issue to you, provided it is not already assigned.

Please note that you can have a maximum of 3 issues assigned to you at any given time.

Pull request guidelines​

To help us review and merge your PRs quickly, please follow these guidelines. PRs that do not meet these standards may be closed.

All PRs should be linked to an existing issue in our tracker. This ensures that every change has been discussed and is aligned with the project's goals before any code is written.

  • For bug fixes: The PR should be linked to the bug report issue.
  • For features: The PR should be linked to the feature request or proposal issue that has been approved by a maintainer.

If an issue for your change doesn't exist, please open one first and wait for feedback before you start coding.

2. Keep it small and focused​

We favor small, atomic PRs that address a single issue or add a single, self-contained feature.

  • Do: Create a PR that fixes one specific bug or adds one specific feature.
  • Don't: Bundle multiple unrelated changes (e.g., a bug fix, a new feature, and a refactor) into a single PR.

Large changes should be broken down into a series of smaller, logical PRs that can be reviewed and merged independently.

3. Use draft PRs for work in progress​

If you'd like to get early feedback on your work, please use GitHub's Draft Pull Request feature. This signals to the maintainers that the PR is not yet ready for a formal review but is open for discussion and initial feedback.

4. Ensure all checks pass​

Before submitting your PR, ensure that all automated checks are passing by running npm run preflight. This command runs all tests, linting, and other style checks.

5. Update documentation​

If your PR introduces a user-facing change (e.g., a new command, a modified flag, or a change in behavior), you must also update the relevant documentation in the /docs directory.

See more about writing documentation: Documentation contribution process.

6. Write clear commit messages and a good PR description​

Your PR should have a clear, descriptive title and a detailed description of the changes. Follow the Conventional Commits standard for your commit messages.

  • Good PR title: feat(cli): Add --json flag to 'config get' command
  • Bad PR title: Made some changes

In the PR description, explain the "why" behind your changes and link to the relevant issue (e.g., Fixes #123).

Forking​

If you are forking the repository you will be able to run the Build, Test and Integration test workflows. However in order to make the integration tests run you'll need to add a GitHub Repository Secret with a value of GEMINI_API_KEY and set that to a valid API key that you have available. Your key and secret are private to your repo; no one without access can see your key and you cannot see any secrets related to this repo.

Additionally you will need to click on the Actions tab and enable workflows for your repository, you'll find it's the large blue button in the center of the screen.

Development setup and workflow​

This section guides contributors on how to build, modify, and understand the development setup of this project.

Setting up the development environment​

Prerequisites:

  1. Node.js:
    • Development: Please use Node.js ~20.19.0. This specific version is required due to an upstream development dependency issue. You can use a tool like nvm to manage Node.js versions.
    • Production: For running the CLI in a production environment, any version of Node.js >=20 is acceptable.
  2. Git

Build process​

To clone the repository:

git clone https://github.com/google-gemini/gemini-cli.git # Or your fork's URL
cd gemini-cli

To install dependencies defined in package.json as well as root dependencies:

npm install

To build the entire project (all packages):

npm run build

This command typically compiles TypeScript to JavaScript, bundles assets, and prepares the packages for execution. Refer to scripts/build.js and package.json scripts for more details on what happens during the build.

Enabling sandboxing​

Sandboxing is highly recommended and requires, at a minimum, setting GEMINI_SANDBOX=true in your ~/.env and ensuring a sandboxing provider (e.g. macOS Seatbelt, docker, or podman) is available. See Sandboxing for details.

To build both the gemini CLI utility and the sandbox container, run build:all from the root directory:

npm run build:all

To skip building the sandbox container, you can use npm run build instead.

Running the CLI​

To start the Gemini CLI from the source code (after building), run the following command from the root directory:

npm start

If you'd like to run the source build outside of the gemini-cli folder, you can utilize npm link path/to/gemini-cli/packages/cli (see: docs) or alias gemini="node path/to/gemini-cli/packages/cli" to run with gemini

Running tests​

This project contains two types of tests: unit tests and integration tests.

Unit tests​

To execute the unit test suite for the project:

npm run test

This will run tests located in the packages/core and packages/cli directories. Ensure tests pass before submitting any changes. For a more comprehensive check, it is recommended to run npm run preflight.

Integration tests​

The integration tests are designed to validate the end-to-end functionality of the Gemini CLI. They are not run as part of the default npm run test command.

To run the integration tests, use the following command:

npm run test:e2e

For more detailed information on the integration testing framework, please see the Integration Tests documentation.

Linting and preflight checks​

To ensure code quality and formatting consistency, run the preflight check:

npm run preflight

This command will run ESLint, Prettier, all tests, and other checks as defined in the project's package.json.

ProTip

after cloning create a git precommit hook file to ensure your commits are always clean.

echo "
# Run npm build and check for errors
if ! npm run preflight; then
  echo "npm build failed. Commit aborted."
  exit 1
fi
" > .git/hooks/pre-commit && chmod +x .git/hooks/pre-commit

Formatting​

To separately format the code in this project by running the following command from the root directory:

npm run format

This command uses Prettier to format the code according to the project's style guidelines.

Linting​

To separately lint the code in this project, run the following command from the root directory:

npm run lint

Coding conventions​

  • Please adhere to the coding style, patterns, and conventions used throughout the existing codebase.
  • Consult GEMINI.md (typically found in the project root) for specific instructions related to AI-assisted development, including conventions for React, comments, and Git usage.
  • Imports: Pay special attention to import paths. The project uses ESLint to enforce restrictions on relative imports between packages.

Project structure​

  • packages/: Contains the individual sub-packages of the project.
    • a2a-server: A2A server implementation for the Gemini CLI. (Experimental)
    • cli/: The command-line interface.
    • core/: The core backend logic for the Gemini CLI.
    • test-utils Utilities for creating and cleaning temporary file systems for testing.
    • vscode-ide-companion/: The Gemini CLI Companion extension pairs with Gemini CLI.
  • docs/: Contains all project documentation.
  • scripts/: Utility scripts for building, testing, and development tasks.

For more detailed architecture, see docs/architecture.md.

Debugging​

VS Code​

  1. Run the CLI to interactively debug in VS Code with F5
  2. Start the CLI in debug mode from the root directory: 
    npm run debug
    This command runs node --inspect-brk dist/gemini.js within the packages/cli directory, pausing execution until a debugger attaches. You can then open chrome://inspect in your Chrome browser to connect to the debugger.
  3. In VS Code, use the "Attach" launch configuration (found in .vscode/launch.json).

Alternatively, you can use the "Launch Program" configuration in VS Code if you prefer to launch the currently open file directly, but 'F5' is generally recommended.

To hit a breakpoint inside the sandbox container run:

DEBUG=1 gemini

Note: If you have DEBUG=true in a project's .env file, it won't affect gemini-cli due to automatic exclusion. Use .gemini/.env files for gemini-cli specific debug settings.

React DevTools​

To debug the CLI's React-based UI, you can use React DevTools. Ink, the library used for the CLI's interface, is compatible with React DevTools version 4.x.

  1. Start the Gemini CLI in development mode:

    DEV=true npm start

  2. Install and run React DevTools version 4.28.5 (or the latest compatible 4.x version):

    You can either install it globally:

    npm install -g react-devtools@4.28.5
    react-devtools

    Or run it directly using npx:

    npx react-devtools@4.28.5

    Your running CLI application should then connect to React DevTools.

Sandboxing​

macOS Seatbelt​

On macOS, gemini uses Seatbelt (sandbox-exec) under a permissive-open profile (see packages/cli/src/utils/sandbox-macos-permissive-open.sb) that restricts writes to the project folder but otherwise allows all other operations and outbound network traffic ("open") by default. You can switch to a restrictive-closed profile (see packages/cli/src/utils/sandbox-macos-restrictive-closed.sb) that declines all operations and outbound network traffic ("closed") by default by setting SEATBELT_PROFILE=restrictive-closed in your environment or .env file. Available built-in profiles are {permissive,restrictive}-{open,closed,proxied} (see below for proxied networking). You can also switch to a custom profile SEATBELT_PROFILE=<profile> if you also create a file .gemini/sandbox-macos-<profile>.sb under your project settings directory .gemini.

Container-based sandboxing (all platforms)​

For stronger container-based sandboxing on macOS or other platforms, you can set GEMINI_SANDBOX=true|docker|podman|<command> in your environment or .env file. The specified command (or if true then either docker or podman) must be installed on the host machine. Once enabled, npm run build:all will build a minimal container ("sandbox") image and npm start will launch inside a fresh instance of that container. The first build can take 20-30s (mostly due to downloading of the base image) but after that both build and start overhead should be minimal. Default builds (npm run build) will not rebuild the sandbox.

Container-based sandboxing mounts the project directory (and system temp directory) with read-write access and is started/stopped/removed automatically as you start/stop Gemini CLI. Files created within the sandbox should be automatically mapped to your user/group on host machine. You can easily specify additional mounts, ports, or environment variables by setting SANDBOX_{MOUNTS,PORTS,ENV} as needed. You can also fully customize the sandbox for your projects by creating the files .gemini/sandbox.Dockerfile and/or .gemini/sandbox.bashrc under your project settings directory (.gemini) and running gemini with BUILD_SANDBOX=1 to trigger building of your custom sandbox.

Proxied networking​

All sandboxing methods, including macOS Seatbelt using *-proxied profiles, support restricting outbound network traffic through a custom proxy server that can be specified as GEMINI_SANDBOX_PROXY_COMMAND=<command>, where <command> must start a proxy server that listens on :::8877 for relevant requests. See docs/examples/proxy-script.md for a minimal proxy that only allows HTTPS connections to example.com:443 (e.g. curl https://example.com) and declines all other requests. The proxy is started and stopped automatically alongside the sandbox.

Manual publish​

We publish an artifact for each commit to our internal registry. But if you need to manually cut a local build, then run the following commands:

npm run clean
npm install
npm run auth
npm run prerelease:dev
npm publish --workspaces

Documentation contribution process​

Our documentation must be kept up-to-date with our code contributions. We want our documentation to be clear, concise, and helpful to our users. We value:

  • Clarity: Use simple and direct language. Avoid jargon where possible.
  • Accuracy: Ensure all information is correct and up-to-date.
  • Completeness: Cover all aspects of a feature or topic.
  • Examples: Provide practical examples to help users understand how to use Gemini CLI.

Getting started​

The process for contributing to the documentation is similar to contributing code.

  1. Fork the repository and create a new branch.
  2. Make your changes in the /docs directory.
  3. Preview your changes locally in Markdown rendering.
  4. Lint and format your changes. Our preflight check includes linting and formatting for documentation files. 
    npm run preflight
  5. Open a pull request with your changes.

Documentation structure​

Our documentation is organized using sidebar.json as the table of contents. When adding new documentation:

  1. Create your markdown file in the appropriate directory under /docs.
  2. Add an entry to sidebar.json in the relevant section.
  3. Ensure all internal links use relative paths and point to existing files.

Style guide​

We follow the Google Developer Documentation Style Guide. Please refer to it for guidance on writing style, tone, and formatting.

Key style points​

  • Use sentence case for headings.
  • Write in second person ("you") when addressing the reader.
  • Use present tense.
  • Keep paragraphs short and focused.
  • Use code blocks with appropriate language tags for syntax highlighting.
  • Include practical examples whenever possible.

Linting and formatting​

We use prettier to enforce a consistent style across our documentation. The npm run preflight command will check for any linting issues.

You can also run the linter and formatter separately:

  • npm run lint - Check for linting issues
  • npm run format - Auto-format markdown files
  • npm run lint:fix - Auto-fix linting issues where possible

Please make sure your contributions are free of linting errors before submitting a pull request.

Before you submit​

Before submitting your documentation pull request, please:

  1. Run npm run preflight to ensure all checks pass.
  2. Review your changes for clarity and accuracy.
  3. Check that all links work correctly.
  4. Ensure any code examples are tested and functional.
  5. Sign the Contributor License Agreement (CLA) if you haven't already.

Need help?​

If you have questions about contributing documentation:

  • Check our FAQ.
  • Review existing documentation for examples.
  • Open an issue to discuss your proposed changes.
  • Reach out to the maintainers.

We appreciate your contributions to making Gemini CLI documentation better!