Pr Review

PR Review

Review a GitHub PR's diff and submit a single GitHub review with inline comments identifying bugs, performance issues, security concerns, and improvements.

Arguments

• $ARGUMENTS (optional): The PR number to review. If not provided, detect the PR associated with the current branch.

Step 1: Identify the PR

1. Get the repository:

   gh repo view --json nameWithOwner -q '.nameWithOwner'
   

2. If a PR number was provided in $ARGUMENTS, use it directly.
3. If no PR number was provided, detect the PR for the current branch:

   gh pr list --head "$(git branch --show-current)" --json number,title,url --limit 1
   

4. If no PR is found, inform the user and stop.
5. Fetch PR metadata:

   gh pr view <NUMBER> --json number,title,url,headRefName,baseRefName,author,body
   

6. Show the PR title and URL for confirmation before proceeding.

Step 2: Fetch the Diff and Changed Files

1. Get the full diff:

   gh pr diff <NUMBER>
   

2. Get the list of changed files with line counts:

   gh pr view <NUMBER> --json files --jq '.files[] | "\(.path) +\(.additions) -\(.deletions)"'
   

Step 3: Analyze Each Changed File

For each changed file in the diff:

1. Read the full file for context (not just the diff) using the Read tool.
2. Understand the purpose of the changes from the diff hunks and surrounding code.
3. Review for issues across these categories:

4. Trace dependencies — use Grep/Glob to check callers, interfaces, and types affected by the change when relevant.
5. Check the PR description — verify the code matches what the author says they changed.

Review guidelines

• Focus on substantive issues — skip formatting nitpicks, trivial style preferences, and obvious code.
• Every comment must be actionable — say what to change, not just what's wrong.
• Include a concrete code suggestion when possible.
• Be respectful and constructive. Assume the author is competent.
• Don't comment on unchanged code unless a change introduces an issue with it.
• For large PRs (20+ files), prioritize critical and security issues. Mention that a full review is recommended.

Step 4: Present Findings

Display ALL findings sorted by severity (critical first), then by file order in the diff.

For each finding:

### #N — [TAG] file/path.ts:L<line>
**Issue**: [Clear, concise description of the problem]
**Suggestion**: [Concrete fix or code change]

After presenting all findings:

• Show a summary count: Found X issues: N critical, N security, N bugs, N improvements...
• If no issues found, say so clearly.

Then ask:

Ready to submit this review? Enter "yes" to post all comments, "remove N,N" to drop specific items, or "edit N" to modify a comment before posting.

Step 5: Submit the Review

Submit a single review using the GitHub API with event COMMENT:

gh api repos/{owner}/{repo}/pulls/{number}/reviews --method POST --input /tmp/pr-review-payload.json

Build the JSON payload with all comments. Each comment needs:

• path: file path relative to repo root
• line: the line number in the diff (use the new file line number for added/modified lines)
• side: "RIGHT" for comments on the new version of the code
• body: the review comment text with tag, issue description, and suggestion. Always append \n\n---\n_[Generated by AI]_ at the end of every comment body

Building the review payload

Construct a temporary JSON file with the review data:

{
  "event": "COMMENT",
  "body": "Review summary — found N issues across M files.",
  "comments": [
    {
      "path": "src/auth.ts",
      "line": 45,
      "side": "RIGHT",
      "body": "🔴 **Critical**: Missing null check on `user` before accessing `.id`. This will throw if the query returns no results.\n\n**Suggestion**:\n```ts\nif (!user) {\n  throw new NotFoundError('User not found');\n}\n```\n\n---\n_[Generated by AI]_"
    }
  ]
}

Submit with:

gh api repos/{owner}/{repo}/pulls/{number}/reviews --method POST --input /tmp/pr-review-payload.json

Clean up the temp file after submission.

Line number mapping

• For comments on added or modified lines: use the line number from the new file (+ side of the diff), set side: "RIGHT".
• For comments on deleted lines: use the line number from the old file (- side of the diff), set side: "LEFT".
• To find the correct line number, parse the diff hunk headers (@@ -old_start,old_count +new_start,new_count @@) and count lines from there.

Step 6: Confirmation

After successful submission:

## Review Submitted

PR #<number> — <title>
URL: <review URL>

Posted <N> inline comments across <M> files.

If submission fails, show the error and suggest the user check their gh auth permissions.