GitLab MCP Server

create_merge_request

Create a new merge request in a GitLab project by specifying source and target branches, title, description, and optional details like assignees or labels.

Instructions

Create a new merge request in a GitLab project

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "project_id": "<project_id>",
      "title": "<title>",
      "source_branch": "<source_branch>",
      "target_branch": "<target_branch>"
    },
    "name": "create_merge_request"
  }
}

Input Schema

Name	Required	Description
`project_id`	Yes	Project ID or complete URL-encoded path to project
`title`	Yes	Merge request title
`description`	No	Merge request description
`source_branch`	Yes	Branch containing changes
`target_branch`	Yes	Branch to merge into
`assignee_ids`	No	The ID of the users to assign the MR to
`reviewer_ids`	No	The ID of the users to assign as reviewers of the MR
`labels`	No	Labels for the MR
`draft`	No	Create as draft merge request
`allow_collaboration`	No	Allow commits from upstream members

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.0.0Jan 3, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```
First observedNov 16, 2025

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden for behavioral disclosure. It states the action ('create') which implies a write operation, but doesn't mention required permissions, whether the operation is idempotent, potential side effects (e.g., notifications sent), or error conditions. This leaves significant gaps for an agent to understand the tool's behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, clear sentence with zero wasted words. It's appropriately sized for a tool with comprehensive schema documentation and gets straight to the point without unnecessary elaboration.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with 10 parameters and no annotations or output schema, the description is insufficient. It doesn't explain what happens after creation (e.g., returns a merge request object, triggers workflows), error handling, or integration with sibling tools like 'list_merge_requests' or 'update_merge_request'. The context demands more behavioral information.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema description coverage is 100%, so the schema already documents all 10 parameters thoroughly. The description adds no additional parameter semantics beyond what's in the schema, but doesn't need to since the schema provides complete coverage. This meets the baseline expectation when schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('create') and resource ('new merge request in a GitLab project'), making the purpose immediately understandable. It doesn't explicitly distinguish from sibling tools like 'create_issue' or 'create_branch', but the specificity of 'merge request' inherently differentiates it within the GitLab context.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives like 'create_issue' or 'update_merge_request'. It doesn't mention prerequisites (e.g., needing an existing project or branches) or contextual cues for when creating a merge request is appropriate versus other actions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.