Drop-in Codex AI agent with GitHub Models

_CODEX_GITHUB_MODELS.md

This is a drop-in, zero-config Actions harness for OpenAI's Codex agent. It uses GitHub Models for inference, so you don't need to set up any secrets - just copy-pasting the action into your repo should work as-is.

You may need to go into your settings and check the "allow Actions to open PRs" checkbox.

To use it, open an issue in your repo with [codex] in the issue name.

codex.yml

name: Codex on GitHub Models

on:
  issues:
    types: [opened]

jobs:
  process-issue:
    if: contains(github.event.issue.title, '[codex]')
    runs-on: ubuntu-latest
    permissions:
      contents: write
      issues: write
      pull-requests: write
      models: read

    steps:
      - name: Checkout repository
        uses: actions/checkout@v3

      - name: Setup Node.js
        uses: actions/setup-node@v3
        with:
          node-version: '22'

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

      - name: Process issue with Codex
        env:
          OPENAI_API_KEY: ${{ secrets.GITHUB_TOKEN }}
          ISSUE_BODY: ${{ github.event.issue.body }}
          ISSUE_NUMBER: ${{ github.event.issue.number }}
          ISSUE_TITLE: ${{ github.event.issue.title }}
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          INSTRUCTION="$ISSUE_TITLE  --- $ISSUE_BODY"
          
          BRANCH_NAME="codex/issue-$ISSUE_NUMBER"
          git checkout -b $BRANCH_NAME

          export OPENAI_BASE_URL=https://models.github.ai/inference

          # any provider string would work here, it's just so codex knows it's using a custom model
          codex --approval-mode full-auto --provider github --model openai/gpt-4.1 --quiet "$INSTRUCTION"
          
          if [[ -n $(git status --porcelain) ]]; then
            git config user.name "GitHub Models Codex Bot"
            git config user.email "[email protected]"
            
            git add .
            git commit -m "Codex changes for issue #$ISSUE_NUMBER"
            git push origin $BRANCH_NAME
            
            # Create PR and comment on issue using the same token
            gh pr create --title "Codex: ${{ github.event.issue.title }}" \
              --body "Auto-generated by Codex for issue #$ISSUE_NUMBER" \
              --base ${{ github.event.repository.default_branch }} \
              --head $BRANCH_NAME
              
            gh issue comment $ISSUE_NUMBER --body "Codex created a PR for this issue"
          else
            gh issue comment $ISSUE_NUMBER --body "Codex processed this issue but made no changes"
          fi

Hi thank you for this, can you share few example prompts (in the issue) that you used if you don't mind, doesnt matter what i specify in the body i always run into "Codex processed this issue but made no changes".

I tried it with some test prompts like "can you remove this Action workflow I'm not using", or "can you add a README to this project". I think you could probably remove --quiet and read the workflow log to get a better sense of what Codex is doing and thinking about.