How to Comment on a Pull Request From a Workflow in GitHub Actions

actions/github-script calls the REST API with the built-in token to leave a PR comment.

Use actions/github-script to call issues.createComment with the PR number and your message. Grant pull-requests: write permission.

Steps

• Add permissions: pull-requests: write to the job.
• Use actions/github-script with github.rest.issues.createComment.
• Pass context.issue.number as the PR number.

Workflow

permissions:
  pull-requests: write
jobs:
  comment:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/github-script@v7
        with:
          script: |
            await github.rest.issues.createComment({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
              body: 'Build passed and coverage is 92%.'
            })

Gotchas

• On pull_request from a fork, GITHUB_TOKEN is read-only; use pull_request_target carefully.
• Find and update an existing comment to avoid spamming a new one each run.

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