checkout-pr

name	checkout-pr
description	Review a GitHub PR and answer questions about it

Review the PR identified by the user's invocation arguments using the gh CLI.

Important: Do not push commits or reply to PR comments without explicit user approval. Always ask first.

Assumption: This workflow assumes you are already running in a git worktree that has the PR branch checked out. The checkout CLI normally handles worktree setup before starting the agent.

1. First, fetch the PR details:

   • Run gh pr view <PR_NUMBER> --json title,body,files,additions,deletions,author,baseRefName,headRefName,state,mergeable,reviewDecision
   • Run gh pr diff <PR_NUMBER> to get the full diff

2. Summarize the PR:

   • Title and author
   • What the PR is doing at a high level
   • Key files changed and their purpose
   • Any notable patterns or architectural decisions

3. Then ask the user what specific questions they have about the PR. Common questions might include:

   • Why certain code can be deleted
   • How a feature flag cleanup affects the codebase
   • What the test changes are validating
   • Whether there are any concerns with the approach

4. When answering questions:

   • Reference specific lines from the diff when relevant
   • Use gh pr diff <PR_NUMBER> to get more context if needed
   • If you need to understand existing code better, read files directly (you're already in the worktree)
   • Explain the "why" behind changes, not just the "what"
   • When linking to files, use paths relative to the current directory (e.g., multiplayer/lib/rust_process.ts:2465)
   • When providing a local path, also remind the user: "To compare against the base branch (<baseRefName>), use Cmd+Shift+G M → GitLens: Open Changes with Branch"

5. When resolving comments, please DO NOT push the commit until approval by the user.

6. Replying to PR review comments:

   • When the user asks you to reply to a review comment, use: gh api -X POST repos/{owner}/{repo}/pulls/<PR_NUMBER>/comments -F body="<your_reply>" -F in_reply_to=<COMMENT_ID>
   • The comment ID is the numeric ID from the review comment URL (e.g., https://github.com/{owner}/{repo}/pull/123#discussion_r12345 → comment ID is 12345)
   • Example: gh api -X POST repos/{owner}/{repo}/pulls/123/comments -F body="Done in abc123def" -F in_reply_to=12345
   • Note: Use -F (not -f) for the in_reply_to parameter since it must be passed as a number