GitLab MCP Server

Instructions

Implementation Reference

• src/api/merge-requests.ts:97-118 (handler)

  The implementation of the mergeMergeRequest function which performs the API call to merge a merge request.

  export async function mergeMergeRequest(
    projectId: string,
    mergeRequestIid: number,
    options: {
      merge_commit_message?: string;
      should_remove_source_branch?: boolean;
      merge_when_pipeline_succeeds?: boolean;
      sha?: string;
    } = {}
  ): Promise<GitLabMergeRequest> {
    if (!projectId?.trim()) {
      throw new Error("Project ID is required");
    }
    if (!mergeRequestIid || mergeRequestIid < 1) {
      throw new Error("Valid merge request IID is required");
    }
  
    const endpoint = `/projects/${encodeProjectId(projectId)}/merge_requests/${mergeRequestIid}/merge`;
  
    const mergeRequest = await gitlabPut<GitLabMergeRequest>(endpoint, options);
    return GitLabMergeRequestSchema.parse(mergeRequest);
  }

• src/schemas.ts:488-495 (schema)

  The Zod schema definition for the input arguments of the merge_merge_request tool.

  export const MergeMergeRequestSchema = z.object({
    project_id: z.string().describe("Project ID or URL-encoded path"),
    merge_request_iid: z.number().describe("Merge request internal ID"),
    merge_commit_message: z.string().optional().describe("Custom merge commit message"),
    should_remove_source_branch: z.boolean().optional().describe("Remove source branch after merge"),
    merge_when_pipeline_succeeds: z.boolean().optional().describe("Merge when pipeline succeeds"),
    sha: z.string().optional().describe("SHA that must match the source branch HEAD")
  });

• src/server.ts:200-204 (registration)

  Registration of the merge_merge_request tool in the server definition.

  {
    name: "merge_merge_request",
    description: "Merge a merge request in a GitLab project",
    inputSchema: zodToJsonSchema(MergeMergeRequestSchema)
  },