Connecting Claude to GitHub transforms your development workflow in ways that feel like having a senior engineer reviewing every single commit. In 2026, the two main approaches are: using Claude Code (Anthropic's dedicated coding CLI), or building custom GitHub Actions workflows that call the Claude API for automated code review, documentation generation, and test writing on every pull request.
Claude Code (CLI): Interactive coding assistant in your terminal. Directly edits files, runs commands, reads your repo. GitHub Actions + API: Automated review bot that comments on every PR, runs on push, requires no developer interaction.
Method 1 — Claude Code CLI
Claude Code is Anthropic's official command-line tool that gives Claude direct access to your codebase. It can read files, make edits, run tests, and push commits — turning it into an agentic developer that works inside your repository.
Install Claude Code
Requires Node.js 18+. Run the install command from your terminal. You'll authenticate with your Anthropic API key on first launch.
Open Your Repo Directory
Navigate to your project root and launch Claude Code. It immediately reads your file structure and understands the codebase context.
Give Natural Language Instructions
"Review the auth module for security issues", "Write unit tests for the payment service", "Refactor this function to use async/await" — Claude makes the changes directly.
# Install globally via npm npm install -g @anthropic-ai/claude-code # Launch in your project directory cd my-project claude # Example commands inside Claude Code > Review this PR diff for bugs and security issues > Write tests for src/api/users.js > Update the README to reflect recent changes
Method 2 — GitHub Actions Auto-Review Bot
For teams that want Claude reviewing every PR automatically without any manual steps, a GitHub Actions workflow is the answer. On every pull request, the workflow extracts the diff, sends it to Claude API, and posts the review as a PR comment — all without any developer needing to interact with Claude directly.
name: Claude Code Review on: pull_request: types: [opened, synchronize] jobs: claude-review: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 with: fetch-depth: 0 - name: Get PR diff run: | git diff origin/${{ github.base_ref }}...HEAD \ > pr_diff.txt - name: Review with Claude env: ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }} run: | DIFF=$(cat pr_diff.txt) RESPONSE=$(curl -s https://api.anthropic.com/v1/messages \ -H "x-api-key: $ANTHROPIC_API_KEY" \ -H "anthropic-version: 2023-06-01" \ -H "content-type: application/json" \ -d "{ \"model\": \"claude-sonnet-4-20250514\", \"max_tokens\": 1024, \"messages\": [{ \"role\": \"user\", \"content\": \"Review this PR diff for bugs, security issues, and improvements:\n\n$DIFF\" }] }") echo "$RESPONSE" > review.json - name: Post review comment uses: actions/github-script@v7 with: script: | // Parse and post Claude's review as PR comment const review = require('./review.json'); const body = review.content[0].text; github.rest.issues.createComment({ issue_number: context.issue.number, owner: context.repo.owner, repo: context.repo.repo, body });
Setting Up Your API Key in GitHub Secrets
Get API Key
Go to console.anthropic.com → API Keys → Create new key. Copy it immediately (shown only once).
Add to GitHub Secrets
In your repo: Settings → Secrets and variables → Actions → New repository secret. Name it ANTHROPIC_API_KEY.
Test the Workflow
Open a test PR with a small change. The Actions tab will show the Claude review workflow running. After completion, Claude's review appears as a comment on the PR.
Add a diff size check before calling Claude — skip the API call if the diff is less than 50 lines (trivial changes). This prevents API costs from piling up on formatting-only commits while keeping reviews on meaningful code changes.
When implementing Claude with GitHub, it's crucial to establish clear guidelines for what Claude should and shouldn't do. Create a .claude-config.json file in your repository root that specifies review priorities, coding standards, and security policies. This ensures Claude's reviews align with your team's specific requirements and coding conventions, making the automated feedback more relevant and actionable.
Security considerations are paramount when connecting AI to your codebase. Never commit your Anthropic API key directly to your repository—always use GitHub Secrets or environment variables. Additionally, consider implementing rate limiting on your GitHub Actions workflow to prevent unexpected API costs during mass PR submissions. For enterprise teams, you may want to set up a proxy server that logs all Claude API calls for compliance and auditing purposes.
The future of AI-assisted development extends beyond code review. Teams are now using Claude to automatically generate pull request descriptions, suggest code refactoring opportunities, identify potential performance bottlenecks, and even write comprehensive documentation for new features. As Claude's capabilities continue to evolve, we can expect even deeper integration with development workflows, potentially including real-time code suggestions during development and automated bug detection before code is even committed.
Frequently Asked Questions
Claude Code CLI is an interactive tool that runs in your terminal, allowing you to have real-time conversations with Claude about your code. It's ideal for active development sessions where you want immediate feedback and assistance. GitHub Actions integration, on the other hand, is fully automated—it runs in the background on every pull request without requiring any manual intervention. Use Claude Code for interactive development and GitHub Actions for automated code review workflows.
Costs depend on your usage pattern. Claude Code CLI requires an Anthropic API key, with pricing based on token usage (approximately $3 per million input tokens and $15 per million output tokens for Claude Sonnet). GitHub Actions integration costs the same per API call, but you can control costs by implementing filters (like skipping small diffs). For a typical team reviewing 50 PRs per month with moderate-sized diffs, expect to spend $50-150 monthly on API costs.
Yes, Claude Code can read and understand your entire repository structure. When you launch Claude Code in your project directory, it automatically indexes your file structure and can reference any file in your codebase. For GitHub Actions, you can configure the workflow to include relevant files in the context sent to Claude, though you'll need to be mindful of token limits. Claude's context window is 200K tokens, which can accommodate most codebases when used strategically.
Anthropic takes security seriously and has robust data protection measures in place. Your code is encrypted in transit and at rest, and Anthropic does not use your code to train their models. However, for highly sensitive codebases (financial systems, proprietary algorithms, etc.), you should review Anthropic's data handling policies and consider implementing additional security measures like API gateways, audit logging, and access controls. Many enterprises use Claude successfully for code review with proper security protocols in place.
With Claude Code CLI, yes—Claude can directly edit files and push commits to fix issues it identifies. You can instruct it to "fix the security vulnerability in the auth module" and it will make the necessary changes. For GitHub Actions integration, Claude typically posts review comments with suggestions rather than making automatic changes, though you can configure the workflow to apply fixes automatically if desired. Most teams prefer the review-and-approve workflow to maintain code quality control.