GitLab MCP Server

Instructions

Implementation Reference

• src/api/merge-requests.ts:120-135 (handler)

  The core handler implementation for add_merge_request_comment.

  export async function addMergeRequestComment(projectId: string, mergeRequestIid: number, body: string): Promise<GitLabComment> {
    if (!projectId?.trim()) {
      throw new Error("Project ID is required");
    }
    if (!mergeRequestIid || mergeRequestIid < 1) {
      throw new Error("Valid merge request IID is required");
    }
    if (!body?.trim()) {
      throw new Error("Comment body is required");
    }
  
    const endpoint = `/projects/${encodeProjectId(projectId)}/merge_requests/${mergeRequestIid}/notes`;
  
    const comment = await gitlabPost<GitLabComment>(endpoint, { body });
    return GitLabCommentSchema.parse(comment);
  }

• src/schemas.ts:497-503 (schema)

  Input schema definition for the add_merge_request_comment tool.

  export const AddMergeRequestCommentSchema = z.object({
    project_id: z.string().describe("Project ID or URL-encoded path"),
    merge_request_iid: z.number().describe("Merge request internal ID"),
    body: z.string().describe("Content of the comment")
  });
  
  // Comment response schema

• src/server.ts:206-210 (registration)

  Tool registration in the MCP server.

      name: "add_merge_request_comment",
      description: "Add a comment to a merge request in a GitLab project",
      inputSchema: zodToJsonSchema(AddMergeRequestCommentSchema)
    }
  ]