Reviewing GitLab MR Comments

Overview

Use glab to fetch MR comments in the current repository, summarize review feedback, confirm understanding, then propose either a simple action checklist or a full plan before executing changes. Prefer line_range for multi-line comments. Default output is comments + line ranges only (no code snippet).

Core principle: Read all comments → confirm understanding → choose checklist vs plan → get approval → execute.

Announce at start: "I'm using the reviewing-gitlab-mr-comments skill to review GitLab MR feedback."

Prerequisites

• glab installed and authenticated.
• Run from the local repository that owns the MR.

Optional checks:

glab auth status

Inputs

Accept either:

• MR IID (e.g., 123)
• MR URL (e.g., https://gitlab.com/group/project/-/merge_requests/123)

If not provided, ask for it.

Workflow

Step 1: Fetch MR and Comments

Prefer glab commands, using IID or URL:

glab mr view <mr> --comments

If you need to see the code under review:

glab mr diff <mr>

If you need to map comments to files/lines (and include multi-line ranges), query discussions:

project_id=$(glab repo view -F json | python3 - <<'PY'
import json,sys
print(json.load(sys.stdin)["id"])
PY
)
glab api "projects/${project_id}/merge_requests/<mr>/discussions"

Then format discussions into a readable list with ranges (comments + line numbers only):

glab api "projects/${project_id}/merge_requests/<mr>/discussions" | \
  ./scripts/mr_discussions_to_md.py

To include code snippets (with context lines) and still show comments:

glab api "projects/${project_id}/merge_requests/<mr>/discussions" | \
  ./scripts/mr_discussions_to_md.py --repo-root "$(pwd)" --context 3 --snippet

Notes:

• The formatter prefers position.line_range.start/end. It falls back to new_line/old_line only when no range exists.
• If files are missing (e.g., deleted or not in the current checkout), the snippet will be marked unavailable.
• Use --snippet to enable snippet output; default is no snippet.

Step 2: Summarize Feedback

Produce a structured summary:

• By thread or file
• Actionable requests vs questions
• Conflicts or ambiguity

Step 3: Confirm Understanding

Ask the user to confirm the summary or clarify any ambiguous items.

Step 4: Decide Checklist vs Plan

Use a simple action checklist when:

• Changes are localized
• No architectural changes
• 1–2 files, low risk

Use a plan when:

• Multiple files/modules
• Conflicting comments or tradeoffs
• Non-trivial refactor or behavior changes

Step 5: Propose Next Steps

Checklist output (simple cases):

• Bullet list of concrete actions
• Verification steps

Plan output (complex cases):

• Phased steps with file targets
• Risks and validations

Then ask for approval: "Do you want me to proceed?"

Step 6: Execute After Approval

Only implement after the user confirms.

Quick Reference

Step	Action
Identify MR	Accept IID or URL; ask if missing
Fetch comments	glab mr view <mr> --comments
Fetch ranges	glab api ".../merge_requests/<mr>/discussions"
Format	./scripts/mr_discussions_to_md.py --repo-root "$(pwd)"
Summarize	Group by thread/file; mark conflicts
Choose output	Checklist for simple; plan for complex
Execute	Only after approval

Common Mistakes

Skipping understanding confirmation

• Problem: Misinterprets review intent
• Fix: Ask for confirmation before planning

Jumping to code changes

• Problem: Skips the plan/approval gate
• Fix: Always ask for approval

Using the wrong repository context

• Problem: Fetches the wrong MR
• Fix: Run in the repo that owns the MR

Only using single-line fields

• Problem: Inline comments are multi-line in GitLab but appear as a single line
• Fix: Prefer position.line_range.start/end and only fall back to new_line/old_line

Example

MR: 123

Summary:
- fileA.ts: fix null handling
- fileB.ts: add tests

This is small and localized.

Checklist:
1) Fix null handling in fileA.ts
2) Add tests in fileB.ts
3) Run build/compile

Proceed?