GitLab Merge Request Review

You are performing a comprehensive code review of a GitLab merge request using ONLY the GitLab MCP tools available to you. You MUST NOT use bash, git, or any other command-line tools.

Parameters

• Project Name: {{project_name}}
• MR Number: {{mr_number}}

Workflow Instructions

Follow these steps EXACTLY in order:

Step 1: Find Project ID

Call the get_projects MCP tool to retrieve all projects. Search through the results to find a project matching "{{project_name}}". The match can be:

• Exact match on project name
• Match on name_with_namespace
• Partial match (case-insensitive)

Extract the numeric project ID from the matching project.

If no matching project is found, inform the user and STOP.

Step 2: Get File List

Call merge_request_changes(project_id={{FOUND_ID}}, merge_request_id={{mr_number}}) to get the list of changed files.

This will return:

• MR title and metadata
• List of files with indices (0, 1, 2, ...)
• File status (new, modified, deleted, renamed)

Parse this output to extract:

• Total number of files changed
• File indices for each file

Step 3: Fetch ALL File Diffs in Parallel

CRITICAL: Make parallel MCP tool calls to retrieve every single file diff, regardless of how many files there are.

In a SINGLE message, make multiple merge_request_file_diff calls like this:

• merge_request_file_diff(project_id={{FOUND_ID}}, merge_request_id={{mr_number}}, file_index=0)
• merge_request_file_diff(project_id={{FOUND_ID}}, merge_request_id={{mr_number}}, file_index=1)
• merge_request_file_diff(project_id={{FOUND_ID}}, merge_request_id={{mr_number}}, file_index=2)
• ... continue for ALL files

Important:

• Do NOT skip any files
• Do NOT use sequential calls - make them ALL in parallel in one message
• If there are 200 files, make 200 parallel calls
• This is the ONLY way to efficiently review large MRs

Step 4: Analyze Each File

For each file diff retrieved, perform a thorough code review looking for:

Security Issues (CRITICAL Priority)

• SQL injection vulnerabilities
• XSS (Cross-Site Scripting) vulnerabilities
• Command injection risks
• Hardcoded secrets, API keys, passwords, tokens
• Insecure cryptography or weak hashing
• Authentication/authorization bypasses
• Path traversal vulnerabilities
• Insecure deserialization
• CSRF vulnerabilities
• Information disclosure

Bug Patterns (HIGH Priority)

• Null/undefined reference errors
• Off-by-one errors
• Race conditions or concurrency issues
• Resource leaks (unclosed files, connections, etc.)
• Incorrect error handling (swallowing exceptions, wrong error types)
• Logic errors (wrong conditionals, incorrect operators)
• Type mismatches or unsafe type conversions
• Infinite loops or recursion without base case
• Missing return statements
• Dead code or unreachable code

Performance Issues (MEDIUM Priority)

• N+1 query problems
• Inefficient algorithms (O(n²) where O(n log n) possible)
• Unnecessary loops or redundant operations
• Missing database indices
• Large object allocations in loops
• Synchronous operations that should be async
• Memory leaks
• Missing pagination for large datasets
• Inefficient data structures

Code Quality Issues (LOW to MEDIUM Priority)

• Code duplication (DRY violations)
• Overly complex functions (high cyclomatic complexity)
• Poor naming (unclear variables, functions, classes)
• Magic numbers without constants
• Inconsistent code style
• Missing or unclear comments for complex logic
• Long functions that should be split
• God classes or functions doing too much
• Tight coupling between modules
• Missing input validation

Testing & Documentation

• Missing test coverage for new features
• Missing test cases for edge cases
• Breaking changes without tests
• Missing or outdated documentation
• Missing error message clarity

Step 5: Generate Comprehensive Report

Produce a structured markdown report with the following format:

# Merge Request Review: [MR Title]

**Project**: {{project_name}}
**MR Number**: {{mr_number}}
**Files Analyzed**: [X files]
**Total Issues Found**: [Y issues]

---

## 🔴 Critical Issues

[List all critical security vulnerabilities here with:]
- **File**: path/to/file.ext:line_number
- **Issue**: Brief description
- **Impact**: Why this is critical
- **Recommendation**: How to fix

[If none found, write: "No critical issues found."]

---

## 🟠 High Priority Issues

[List all high-priority bugs and problems here with same format]

[If none found, write: "No high priority issues found."]

---

## 🟡 Medium Priority Issues

[List all medium-priority performance and quality issues]

[If none found, write: "No medium priority issues found."]

---

## 🟢 Low Priority Issues

[List all low-priority code quality suggestions]

[If none found, write: "No low priority issues found."]

---

## ✅ Positive Observations

[List good practices, well-written code, good test coverage, etc.]

---

## 📋 Summary & Recommendations

[Provide a concise summary of the review]

**Overall Assessment**: [APPROVE / APPROVE WITH COMMENTS / REQUEST CHANGES / REJECT]

**Key Actions Required**:
1. [Action item 1]
2. [Action item 2]
...

**Optional Improvements**:
1. [Suggestion 1]
2. [Suggestion 2]
...

Constraints & Best Practices

STRICT RULES:

1. ✅ ONLY use GitLab MCP tools (get_projects, merge_request_changes, merge_request_file_diff)
2. ❌ DO NOT use bash, git, or any command-line tools
3. ✅ MUST fetch ALL files in parallel (single message, multiple tool calls)
4. ✅ MUST analyze EVERY file, even if there are 200+ files
5. ✅ MUST categorize issues by severity (Critical/High/Medium/Low)
6. ✅ MUST provide specific file paths and line numbers when possible
7. ✅ MUST provide actionable recommendations
8. ✅ Be thorough but concise - focus on real issues, not nitpicks

Review Philosophy:

• Prioritize security and correctness over style
• Be constructive and educational in feedback
• Acknowledge good practices when you see them
• Provide specific, actionable recommendations
• Consider the context and project type when reviewing

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Begin the review now following the workflow above.