codex exec Complete Guide: Non-Interactive Mode, Exit Codes & CI Automation

codex exec [options] "<task>"

# Simplest form: just provide the task
$ codex exec "Add JSDoc comments to all public methods in src/utils.ts"

# Specify model + quiet mode (CI-friendly)
$ codex exec --model gpt-4.1-mini --quiet \
    "Read git log --oneline -20 and update CHANGELOG.md"

# Full-auto mode (recommended for CI with --quiet)
$ codex exec --full-auto --quiet \
    "Run npm test; if any tests fail, fix the relevant files in src/"

# No restrictions (use with caution in production)
$ codex exec --dangerously-auto-approve-everything \
    "Install dependencies, build the project, and run end-to-end tests"

# Default suggest mode: outputs a code review report, modifies nothing
$ codex exec "Review the code in src/ and list potential performance issues"

# Explicit equivalent
$ codex exec --approval-mode suggest \
    "Review the code in src/ and list potential performance issues"

# auto-edit: modifies files automatically; good for formatting, adding comments
$ codex exec --approval-mode auto-edit \
    "Replace all console.log calls in src/ with logger.debug"

# full-auto: fully automated within the sandbox; handles most CI tasks well
$ codex exec --full-auto --quiet \
    "Run npm run lint and fix all auto-fixable ESLint errors"

# Equivalent explicit form
$ codex exec --approval-mode full-auto --quiet \
    "Run npm run lint and fix all auto-fixable ESLint errors"

#!/bin/bash
set -e  # Exit immediately if any command fails

# Run a task — will abort the script if it exits non-zero (due to set -e)
codex exec --full-auto --quiet "Update CHANGELOG.md"

# Explicit exit code check
if codex exec --full-auto "Run tests and fix any failing cases"; then
  echo "Task succeeded, ready to commit"
  git add -A && git commit -m "chore: AI auto-fixed tests"
else
  EXIT_CODE=$?
  echo "Task failed with exit code: $EXIT_CODE"
  exit $EXIT_CODE
fi

name: AI Code Review & Changelog

on:
  pull_request:
    branches: [main, develop]
    paths:
      - 'src/**'
      - 'lib/**'
      - '!**/*.md'

permissions:
  contents: write
  pull-requests: write

jobs:
  ai-review:
    runs-on: ubuntu-latest
    timeout-minutes: 15

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0  # Full history required for git diff
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '22'
          cache: 'npm'

      - name: Install project dependencies
        working-directory: .
        run: npm ci

      - name: Install Codex CLI
        run: npm install -g @openai/codex

      - name: Run AI code review
        env:
          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
        working-directory: .
        run: |
          codex exec \
            --model gpt-4.1-mini \
            --full-auto \
            --quiet \
            "Review the changes in this PR (git diff origin/main...HEAD) and write a code review report to .ai-review.md, covering: potential bugs, performance issues, and security vulnerabilities."

      - name: Update CHANGELOG
        env:
          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
        working-directory: .
        run: |
          codex exec \
            --model gpt-4.1-mini \
            --full-auto \
            --quiet \
            "Based on git diff origin/main...HEAD, prepend an Unreleased entry to CHANGELOG.md following Keep a Changelog format. Only modify CHANGELOG.md."

      - name: Commit AI changes
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"
          git add .ai-review.md CHANGELOG.md
          git diff --staged --quiet || git commit -m "chore(ai): update review and changelog [skip ci]"
          git push

stages:
  - ai-review
  - deploy

variables:
  NODE_VERSION: "22"

ai-code-review:
  stage: ai-review
  image: node:22-slim
  only:
    - merge_requests
  variables:
    OPENAI_API_KEY: $OPENAI_API_KEY  # Injected from GitLab CI/CD Variables
  before_script:
    - npm install -g @openai/codex
    - git fetch origin $CI_MERGE_REQUEST_TARGET_BRANCH_NAME
  script:
    - |
      codex exec \
        --model gpt-4.1-mini \
        --full-auto \
        --quiet \
        "Review the changes in this MR (git diff origin/${CI_MERGE_REQUEST_TARGET_BRANCH_NAME}),
        write findings to .ai-review.md: code quality issues, potential bugs, security problems.
        Only modify .ai-review.md, do not touch any other files."
    - |
      codex exec \
        --model gpt-4.1-mini \
        --full-auto \
        --quiet \
        "Based on git diff origin/${CI_MERGE_REQUEST_TARGET_BRANCH_NAME},
        prepend an Unreleased entry to CHANGELOG.md following Keep a Changelog format.
        Only modify CHANGELOG.md."
  after_script:
    - git config user.email "[email protected]"
    - git config user.name "GitLab CI"
    - git add .ai-review.md CHANGELOG.md
    - git diff --staged --quiet || git commit -m "chore(ai): update review and changelog [skip ci]"
    - git push "https://oauth2:${CI_JOB_TOKEN}@${CI_SERVER_HOST}/${CI_PROJECT_PATH}.git"
        "HEAD:${CI_MERGE_REQUEST_SOURCE_BRANCH_NAME}"
  timeout: 10 minutes
  interruptible: true

# Read the last 10 commits and prepend a CHANGELOG entry
$ codex exec --model gpt-4.1-mini --full-auto --quiet \
    "Read git log --oneline -10, prepend a ## [Unreleased] block to CHANGELOG.md with one bullet per commit. Format: - type: description"

# Run lint and automatically fix all fixable errors
$ codex exec --full-auto --quiet \
    "Run npm run lint 2>&1, analyze the output, fix all auto-fixable ESLint errors in src/, then run lint again to confirm zero errors"

# Generate JSDoc for all exported functions in a file
$ codex exec --approval-mode auto-edit \
    "Add complete JSDoc comments to all exported functions in src/utils/helpers.ts, including @param, @returns, and @example. Do not change any function implementations."

# Use the timeout command to prevent the job from hanging indefinitely (5-minute limit)
$ timeout 300 codex exec --full-auto \
    "Write Vitest unit tests for every exported function in src/auth/login.ts. Save to src/auth/__tests__/login.test.ts, covering happy path and edge cases."
RESULT=$?
if [ $RESULT -eq 124 ]; then
  echo "Timed out! Consider breaking this into smaller sub-tasks."
fi

# Low-cost task: mini model + quiet mode (reduces output tokens too)
$ codex exec --model gpt-4.1-mini --quiet --full-auto \
    "Update CHANGELOG.md"

# Timeout guard: prevents runaway token consumption from stuck tasks
$ timeout 180 codex exec --model gpt-4.1-mini --quiet \
    "Summarize recent changes in src/ and write a brief report"

# Path filtering in GitHub Actions (set on.pull_request.paths in YAML)
# ensures the workflow only runs when source files actually change