I'm using a GitHub Actions workflow triggered by the pull_request event (opened and ready_for_review). If someone creates a pull request without assigning any reviewers, I want to automatically convert it to a draft and leave a comment reminding them to add reviewers.

I’ve tried using both gh api and curl with the GitHub REST API to convert the PR to draft, and I’m getting 200 OK responses — but the PR is not actually converted to draft.

Here’s the relevant part of my workflow:

name: Convert PR to Draft if Missing Reviewers

on:
  pull_request:
    types:
      - opened
      - ready_for_review

permissions:
  pull-requests: write
  contents: read

jobs:
  check-pr:
    runs-on: ubuntu-latest
    steps:
      - name: Check and Convert to Draft
        run: |
          REVIEWERS_COUNT=$(jq '.pull_request.requested_reviewers | length' "$GITHUB_EVENT_PATH")
          AUTHOR=$(jq -r '.pull_request.user.login' "$GITHUB_EVENT_PATH")
          PR_NUMBER=$(jq -r '.pull_request.number' "$GITHUB_EVENT_PATH")
          REPO_NAME=$(jq -r '.repository.full_name' "$GITHUB_EVENT_PATH")

          if [ "$REVIEWERS_COUNT" -eq 0 ]; then
            echo "No reviewers assigned. Converting PR to draft..."

            # Attempt to convert PR to draft using the API
            curl -X PATCH \
              -H "Authorization: token $GITHUB_TOKEN" \
              -H "Accept: application/vnd.github+json" \
              -H "Content-Type: application/json" \
              -d '{"draft": true}' \
              "/$REPO_NAME/pulls/$PR_NUMBER"

            # Add a comment to the PR
            gh pr comment "/$REPO_NAME/pull/$PR_NUMBER" \
              --body ":warning: @${AUTHOR} please assign at least one reviewer before marking this PR as ready for review."
          fi
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          GITHUB_EVENT_PATH: ${{ github.event_path }}

Outcome:

• The curl call returns a 200 OK (actually stating Successfully converted PR to draft)
• The comment is successfully posted, so auth and repo info are correct.
• But the PR is NOT marked as a draft in the GitHub UI.

What am I missing here?

I'm using a GitHub Actions workflow triggered by the pull_request event (opened and ready_for_review). If someone creates a pull request without assigning any reviewers, I want to automatically convert it to a draft and leave a comment reminding them to add reviewers.

I’ve tried using both gh api and curl with the GitHub REST API to convert the PR to draft, and I’m getting 200 OK responses — but the PR is not actually converted to draft.

Here’s the relevant part of my workflow:

name: Convert PR to Draft if Missing Reviewers

on:
  pull_request:
    types:
      - opened
      - ready_for_review

permissions:
  pull-requests: write
  contents: read

jobs:
  check-pr:
    runs-on: ubuntu-latest
    steps:
      - name: Check and Convert to Draft
        run: |
          REVIEWERS_COUNT=$(jq '.pull_request.requested_reviewers | length' "$GITHUB_EVENT_PATH")
          AUTHOR=$(jq -r '.pull_request.user.login' "$GITHUB_EVENT_PATH")
          PR_NUMBER=$(jq -r '.pull_request.number' "$GITHUB_EVENT_PATH")
          REPO_NAME=$(jq -r '.repository.full_name' "$GITHUB_EVENT_PATH")

          if [ "$REVIEWERS_COUNT" -eq 0 ]; then
            echo "No reviewers assigned. Converting PR to draft..."

            # Attempt to convert PR to draft using the API
            curl -X PATCH \
              -H "Authorization: token $GITHUB_TOKEN" \
              -H "Accept: application/vnd.github+json" \
              -H "Content-Type: application/json" \
              -d '{"draft": true}' \
              "https://api.github/repos/$REPO_NAME/pulls/$PR_NUMBER"

            # Add a comment to the PR
            gh pr comment "https://github/$REPO_NAME/pull/$PR_NUMBER" \
              --body ":warning: @${AUTHOR} please assign at least one reviewer before marking this PR as ready for review."
          fi
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          GITHUB_EVENT_PATH: ${{ github.event_path }}

Outcome:

• The curl call returns a 200 OK (actually stating Successfully converted PR to draft)
• The comment is successfully posted, so auth and repo info are correct.
• But the PR is NOT marked as a draft in the GitHub UI.

What am I missing here?

• github
• github-actions
• github-api

1 Answer 1

I played around with this one for a while and had to change two things:

1. I don't think the gh rest api supports this so I switched to GraphQL: https://github/actions/toolkit/issues/1165.

2. It does not work in private repos: How to convert a pull-request to draft with github action. It worked for me when I tried in a public repo!

Here is my version of your file with GraphQL:

name: Convert PR to Draft if Missing Reviewers

on:
  pull_request:
    types:
      - opened
      - ready_for_review

permissions:
  pull-requests: write
  contents: write

jobs:
  check-pr:
    runs-on: ubuntu-latest
    steps:
      - name: Check and Convert to Draft
        run: |
          REVIEWERS_COUNT=$(jq '.pull_request.requested_reviewers | length' "$GITHUB_EVENT_PATH")
          AUTHOR=$(jq -r '.pull_request.user.login' "$GITHUB_EVENT_PATH")
          PR_NUMBER=$(jq -r '.pull_request.number' "$GITHUB_EVENT_PATH")
          REPO_NAME=$(jq -r '.repository.full_name' "$GITHUB_EVENT_PATH")

          if [ "$REVIEWERS_COUNT" -eq 0 ]; then
            echo "No reviewers assigned. Converting PR to draft..."

            # Get PR Node ID using GitHub GraphQL API
            PR_NODE_ID=$(curl -s -X POST -H "Authorization: Bearer $GITHUB_TOKEN" \
              -H "Content-Type: application/json" \
              -H "Accept: application/vnd.github+json" \
              --data '{"query": "query { repository(name: \"'${REPO_NAME#*/}'\", owner: \"'${REPO_NAME%/*}'\") { pullRequest(number: '${PR_NUMBER}') { id } } }"}' \
              https://api.github/graphql | jq -r '.data.repository.pullRequest.id')

            echo "PR Node ID: $PR_NODE_ID"

            # Convert PR to draft using GraphQL Mutation
            curl -s -X POST -H "Authorization: Bearer $GITHUB_TOKEN" \
              -H "Content-Type: application/json" \
              -H "Accept: application/vnd.github.v4+json" \
              --data '{"query": "mutation { convertPullRequestToDraft(input: {pullRequestId: \"'${PR_NODE_ID}'\"}) { pullRequest { id number isDraft } } }"}' \
              https://api.github/graphql

            # Add a comment to the PR
            gh pr comment "https://github/$REPO_NAME/pull/$PR_NUMBER" \
              --body ":warning: @${AUTHOR} please assign at least one reviewer before marking this PR as ready for review."
          fi
        env:         
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          GITHUB_EVENT_PATH: ${{ github.event_path }}