---
title: Code Review Tools
description: "GitLab MCP code review tools for merge request workflows. Browse MRs, view diffs, manage discussions, post draft notes, add code suggestions, and handle approvals with AI assistance."
head:
- - meta
- name: keywords
content: GitLab code review, merge requests, MR discussions, draft notes, code suggestions, MCP
---
# GitLab Code Review and MR Tools
Tools for the complete merge request review workflow — browsing MRs, viewing diffs, adding comments, and managing approvals.
## Tools Overview
| Tool | Type | Purpose |
|------|------|---------|
| `browse_merge_requests` | Query | List, get details, view diffs, compare branches |
| `browse_mr_discussions` | Query | View discussion threads and draft notes |
| `manage_merge_request` | Command | Create, update, merge, approve MRs |
| `manage_mr_discussion` | Command | Comments, threads, replies, suggestions |
| `manage_draft_notes` | Command | Batch review with draft comments |
## browse_merge_requests
Find and inspect merge requests.
### Actions
<!-- @autogen:tool browse_merge_requests -->
| Action | Description |
|--------|-------------|
| `list` | List merge requests with filtering |
| `get` | Get single MR by IID or branch name |
| `diffs` | Get file changes/diffs for an MR |
| `compare` | Compare two branches or commits |
<!-- @autogen:end -->
### Examples
::: code-group
```json [List open MRs]
{
"action": "list",
"project_id": "my-org/api",
"state": "opened",
"per_page": 20
}
```
```json [Get MR by IID]
{
"action": "get",
"project_id": "my-org/api",
"merge_request_iid": "42",
"per_page": 20
}
```
```json [View diff]
{
"action": "diffs",
"project_id": "my-org/api",
"merge_request_iid": "42",
"per_page": 100
}
```
```json [Compare branches]
{
"action": "compare",
"project_id": "my-org/api",
"from": "main",
"to": "feature/auth",
"per_page": 20
}
```
```json [List MR versions]
{
"action": "versions",
"project_id": "my-org/api",
"merge_request_iid": "42"
}
```
```json [Get specific version]
{
"action": "version",
"project_id": "my-org/api",
"merge_request_iid": "42",
"version_id": "123"
}
```
:::
### Key Filters for `list`
| Parameter | Description |
|-----------|-------------|
| `state` | `opened`, `closed`, `merged`, `all` |
| `author_username` | Filter by MR author |
| `reviewer_username` | Filter by assigned reviewer |
| `assignee_username` | Filter by assignee |
| `labels` | Filter by labels (comma-separated or array) |
| `milestone` | Filter by milestone title |
| `source_branch` | Filter by source branch |
| `target_branch` | Filter by target branch |
| `wip` | `yes` for drafts, `no` for ready |
| `order_by` | `created_at`, `updated_at`, `priority` |
| `scope` | `created_by_me`, `assigned_to_me`, `all` |
## manage_merge_request
Create and manage merge requests.
### Actions
<!-- @autogen:tool manage_merge_request -->
| Action | Description |
|--------|-------------|
| `create` | Create a new merge request |
| `update` | Update an existing merge request |
| `merge` | Merge an approved merge request |
| `approve` | Approve a merge request |
| `unapprove` | Remove your approval from a merge request |
| `get_approval_state` | Get current approval status and rules |
<!-- @autogen:end -->
### Examples
::: code-group
```json [Create MR]
{
"action": "create",
"project_id": "my-org/api",
"source_branch": "feature/auth",
"target_branch": "main",
"title": "feat: Add authentication",
"description": "Implements JWT auth flow",
"remove_source_branch": true,
"reviewer_ids": ["42"]
}
```
```json [Approve MR]
{
"action": "approve",
"project_id": "my-org/api",
"merge_request_iid": "42"
}
```
```json [Merge MR]
{
"action": "merge",
"project_id": "my-org/api",
"merge_request_iid": "42",
"squash": true,
"should_remove_source_branch": true
}
```
:::
## manage_mr_discussion
Add comments, suggestions, and manage discussion threads.
### Actions
<!-- @autogen:tool manage_mr_discussion -->
| Action | Description |
|--------|-------------|
| `comment` | Add a comment to an issue or merge request |
| `thread` | Start a new discussion thread on an MR |
| `reply` | Reply to an existing discussion thread |
| `update` | Update an existing note/comment |
| `apply_suggestion` | Apply a single code suggestion from a review |
| `apply_suggestions` | Batch apply multiple code suggestions |
| `resolve` | Resolve or unresolve a discussion thread |
| `suggest` | Create a code suggestion on a diff line |
<!-- @autogen:end -->
### Examples
::: code-group
```json [Add comment]
{
"action": "comment",
"project_id": "my-org/api",
"noteable_type": "merge_request",
"noteable_id": "42",
"body": "LGTM! Great work on the tests."
}
```
```json [Code suggestion]
{
"action": "suggest",
"project_id": "my-org/api",
"merge_request_iid": "42",
"comment": "Use optional chaining here",
"suggestion": "const name = user?.name ?? 'Unknown';",
"position": {
"base_sha": "abc123",
"head_sha": "def456",
"start_sha": "ghi789",
"new_path": "src/auth.ts",
"new_line": 15,
"position_type": "text"
}
}
```
```json [Resolve thread]
{
"action": "resolve",
"project_id": "my-org/api",
"merge_request_iid": "42",
"discussion_id": "abc123",
"resolved": true
}
```
:::
## manage_draft_notes
Prepare all review comments before publishing them at once.
### Actions
<!-- @autogen:tool manage_draft_notes -->
| Action | Description |
|--------|-------------|
| `create` | Create a new draft note |
| `update` | Update an existing draft note |
| `publish` | Publish a single draft note |
| `publish_all` | Publish all draft notes at once |
| `delete` | Delete a draft note |
<!-- @autogen:end -->
### Workflow
1. Create multiple draft notes as you review
2. Review all your comments for consistency
3. Publish all at once for a clean review experience
## Related Guides
- [Complete Code Review Guide](/guides/complete-code-review)
- [Code Review Prompts](/prompts/code-review/review-mr)
