GitHub Integration

Codex integrates deeply with GitHub. You can trigger code reviews on pull requests, start cloud tasks from PR comments, and automate issue triage — all by mentioning @codex.

Setup#

1. Go to Codex settings or the Codex app settings
2. Connect your GitHub account
3. Select the repositories you want Codex to access
4. Enable Code review for repositories where you want automatic PR reviews

## Automated PR Reviews

Once enabled, Codex automatically reviews pull requests when they move from draft to ready for review.

What Codex Reviews#

• Logical errors and edge cases
• Security vulnerabilities (injection, XSS, auth issues)
• Race conditions and concurrency bugs
• Missing test coverage
• Style and convention violations (per your AGENTS.md)

Priority Levels#

On GitHub, Codex only flags high-priority issues:

| Priority | Description | Action | |----------|-------------|--------| | P0 | Critical bugs, security vulnerabilities | Must fix before merge | | P1 | Important logic errors, missing edge cases | Should fix before merge |

## @codex Mentions

Code Review#

Comment on any PR:

@codex review

Codex reacts with a look emoji to acknowledge it started, then posts a standard GitHub code review when done.

Focused Review#

@codex review for security vulnerabilities
@codex review for performance issues
@codex review for accessibility regressions

Cloud Tasks from PRs#

Any @codex mention that is not "review" starts a cloud task using the PR as context:

@codex fix the type error on line 42
@codex add tests for the new auth middleware
@codex refactor this to use the repository pattern

Codex creates a cloud task, works on it in a sandboxed environment, and pushes the changes back to the PR.

AGENTS.md for Review Guidelines#

Codex searches your repository for AGENTS.md files and follows review guidelines found in them:

# AGENTS.md

## Review Guidelines
- Always check for SQL injection in database queries
- Verify that all API endpoints have proper authentication
- Ensure new components have corresponding unit tests
- Flag any hardcoded credentials or API keys as P0

Codex applies the guidance from the closest AGENTS.md to each changed file. You can place more specific instructions deeper in the directory tree:

repo/
  AGENTS.md                    # General review rules
  services/
    payments/
      AGENTS.md                # Payment-specific rules (PCI compliance, etc.)
    auth/
      AGENTS.md                # Auth-specific rules (token validation, etc.)

Skills and Automations#

Skills#

With Skills, Codex contributes beyond just writing code:

• Code understanding — Explain complex logic, generate documentation
• Prototyping — Turn designs into working code
• Documentation — Auto-generate and update docs

Automations#

Codex can work unprompted on routine tasks:

• Issue triage — Automatically categorize and label new issues
• Alert monitoring — Respond to CI/CD alerts
• Dependency updates — Create PRs for outdated dependencies

Cloud Task Workflow#

1. Create task — Via @codex mention, the web UI, or CLI
2. Codex works — In a sandboxed cloud environment with your repo
3. Review results — Codex presents diffs and optionally creates a PR
4. Apply or iterate — Accept changes, request modifications, or start a new task

## Next Steps

• Code Review — In-depth review capabilities
• Non-Interactive Mode — CI/CD automation
• AGENTS.md Guide — Configure project instructions