MCP GitLab Server

Instructions

Implementation Reference

• src/mcp_gitlab/tool_handlers.py:446-452 (handler)

  The core handler function that implements the tool logic. Extracts project_id (auto-detects if missing) and mr_iid from arguments, then delegates to GitLabClient.get_merge_request_changes() to fetch the MR changes/diffs.
  def handle_get_merge_request_changes(client: GitLabClient, arguments: Optional[Dict[str, Any]]) -> Dict[str, Any]: """Handle getting merge request changes""" project_id = require_project_id(client, arguments) mr_iid = require_argument(arguments, "mr_iid") return client.get_merge_request_changes(project_id, mr_iid)
• src/mcp_gitlab/tool_handlers.py:1002-1097 (registration)

  The TOOL_HANDLERS dictionary maps tool names (like TOOL_GET_MR_CHANGES) to their handler functions. Used in server.py handle_call_tool() to dispatch tool calls to the correct handler.
  TOOL_HANDLERS = { # List tools TOOL_LIST_PROJECTS: handle_list_projects, TOOL_LIST_ISSUES: handle_list_issues, TOOL_LIST_MRS: handle_list_merge_requests, TOOL_LIST_BRANCHES: handle_list_branches, TOOL_LIST_PIPELINES: handle_list_pipelines, TOOL_LIST_USER_EVENTS: handle_get_user_events, TOOL_LIST_COMMITS: handle_get_commits, TOOL_LIST_REPOSITORY_TREE: handle_get_repository_tree, TOOL_LIST_TAGS: handle_get_tags, TOOL_LIST_RELEASES: handle_list_releases, TOOL_LIST_PROJECT_MEMBERS: handle_get_project_members, TOOL_LIST_PROJECT_HOOKS: handle_get_project_hooks, TOOL_LIST_GROUPS: handle_list_groups, TOOL_LIST_GROUP_PROJECTS: handle_list_group_projects, TOOL_LIST_SNIPPETS: handle_list_snippets, TOOL_LIST_PIPELINE_JOBS: handle_list_pipeline_jobs, TOOL_LIST_PROJECT_JOBS: handle_list_project_jobs, # Get tools TOOL_GET_PROJECT: handle_get_project, TOOL_GET_CURRENT_PROJECT: handle_get_current_project, TOOL_GET_MR_NOTES: handle_get_merge_request_notes, TOOL_GET_CURRENT_USER: handle_get_current_user, TOOL_GET_USER: handle_get_user, TOOL_GET_GROUP: handle_get_group, TOOL_GET_SNIPPET: handle_get_snippet, TOOL_DOWNLOAD_JOB_ARTIFACT: handle_download_job_artifact, TOOL_GET_ISSUE: handle_get_issue, TOOL_GET_MERGE_REQUEST: handle_get_merge_request, TOOL_GET_FILE_CONTENT: handle_get_file_content, TOOL_GET_COMMIT: handle_get_commit, TOOL_GET_COMMIT_DIFF: handle_get_commit_diff, TOOL_GET_MR_APPROVALS: handle_get_merge_request_approvals, TOOL_GET_MR_DISCUSSIONS: handle_get_merge_request_discussions, TOOL_GET_MR_CHANGES: handle_get_merge_request_changes, # Action tools TOOL_CREATE_SNIPPET: handle_create_snippet, TOOL_UPDATE_SNIPPET: handle_update_snippet, TOOL_UPDATE_MR: handle_update_merge_request, TOOL_CLOSE_MR: handle_close_merge_request, TOOL_MERGE_MR: handle_merge_merge_request, TOOL_REBASE_MR: handle_rebase_merge_request, TOOL_APPROVE_MR: handle_approve_merge_request, TOOL_ADD_ISSUE_COMMENT: handle_add_issue_comment, TOOL_ADD_MR_COMMENT: handle_add_merge_request_comment, TOOL_RESOLVE_DISCUSSION: handle_resolve_discussion, TOOL_CREATE_COMMIT: handle_create_commit, TOOL_CHERRY_PICK_COMMIT: handle_cherry_pick_commit, TOOL_COMPARE_REFS: handle_compare_refs, # Search tools TOOL_SEARCH_PROJECTS: handle_search_projects, TOOL_SEARCH_IN_PROJECT: handle_search_in_project, # AI and Advanced Tools TOOL_SUMMARIZE_MR: handle_summarize_merge_request, TOOL_SUMMARIZE_ISSUE: handle_summarize_issue, TOOL_SUMMARIZE_PIPELINE: handle_summarize_pipeline, TOOL_SMART_DIFF: handle_smart_diff, TOOL_SAFE_PREVIEW_COMMIT: handle_safe_preview_commit, TOOL_BATCH_OPERATIONS: handle_batch_operations, # Job and Artifact handlers TOOL_LIST_PIPELINE_JOBS: handle_list_pipeline_jobs, TOOL_DOWNLOAD_JOB_ARTIFACT: handle_download_job_artifact, TOOL_LIST_PROJECT_JOBS: handle_list_project_jobs, # User & Profile handlers TOOL_SEARCH_USER: handle_search_user, TOOL_GET_USER_DETAILS: handle_get_user_details, TOOL_GET_MY_PROFILE: handle_get_my_profile, TOOL_GET_USER_CONTRIBUTIONS_SUMMARY: handle_get_user_contributions_summary, TOOL_GET_USER_ACTIVITY_FEED: handle_get_user_activity_feed, # User's Issues & MRs handlers TOOL_GET_USER_OPEN_MRS: handle_get_user_open_mrs, TOOL_GET_USER_REVIEW_REQUESTS: handle_get_user_review_requests, TOOL_GET_USER_OPEN_ISSUES: handle_get_user_open_issues, TOOL_GET_USER_REPORTED_ISSUES: handle_get_user_reported_issues, TOOL_GET_USER_RESOLVED_ISSUES: handle_get_user_resolved_issues, # User's Code & Commits handlers TOOL_GET_USER_COMMITS: handle_get_user_commits, TOOL_GET_USER_MERGE_COMMITS: handle_get_user_merge_commits, TOOL_GET_USER_CODE_CHANGES_SUMMARY: handle_get_user_code_changes_summary, TOOL_GET_USER_SNIPPETS: handle_get_user_snippets, # User's Comments & Discussions handlers TOOL_GET_USER_ISSUE_COMMENTS: handle_get_user_issue_comments, TOOL_GET_USER_MR_COMMENTS: handle_get_user_mr_comments, TOOL_GET_USER_DISCUSSION_THREADS: handle_get_user_discussion_threads, TOOL_GET_USER_RESOLVED_THREADS: handle_get_user_resolved_threads, }
• src/mcp_gitlab/server.py:772-783 (schema)

  MCP Tool schema definition registered via @server.list_tools(). Defines input parameters: project_id (optional, auto-detected) and required mr_iid (integer). Returned by list_tools() endpoint.
  types.Tool( name="gitlab_get_merge_request_changes", description=desc.DESC_GET_MR_CHANGES, inputSchema={ "type": "object", "properties": { "project_id": {"type": "string", "description": desc.DESC_PROJECT_ID}, "mr_iid": {"type": "integer", "description": desc.DESC_MR_IID} }, "required": ["mr_iid"] } ),
• src/mcp_gitlab/server.py:1243-1294 (registration)

  The @server.call_tool() handler that receives tool calls from MCP client. Looks up handler function via TOOL_HANDLERS[name], executes it with GitLabClient and arguments, handles errors, truncates large responses, and returns JSON.
  async def handle_call_tool( name: str, arguments: dict | None ) -> List[types.TextContent | types.ImageContent | types.EmbeddedResource]: """Handle tool execution with comprehensive error handling""" try: client = get_gitlab_client() # Check if tool exists handler = TOOL_HANDLERS.get(name) if not handler: raise ValueError(f"Unknown tool: {name}") # Execute the handler result = handler(client, arguments) # Truncate response if too large result = truncate_response(result, MAX_RESPONSE_SIZE) return [types.TextContent( type="text", text=json.dumps(result, indent=2) )] except gitlab.exceptions.GitlabAuthenticationError as e: logger.error(f"Authentication failed: {e}") error_response = sanitize_error(e, ERROR_AUTH_FAILED) return [types.TextContent(type="text", text=json.dumps(error_response, indent=2))] except gitlab.exceptions.GitlabGetError as e: response_code = getattr(e, 'response_code', None) if response_code == 404: logger.warning(f"Resource not found: {e}") error_response = sanitize_error(e, ERROR_NOT_FOUND) elif response_code == 429: logger.warning(f"Rate limit exceeded: {e}") error_response = sanitize_error(e, ERROR_RATE_LIMIT) else: logger.error(f"GitLab API error: {e}") error_response = sanitize_error(e) return [types.TextContent(type="text", text=json.dumps(error_response, indent=2))] except gitlab.exceptions.GitlabError as e: logger.error(f"General GitLab error: {e}") error_response = sanitize_error(e) return [types.TextContent(type="text", text=json.dumps(error_response, indent=2))] except ValueError as e: logger.warning(f"Invalid input: {e}") error_response = sanitize_error(e, ERROR_INVALID_INPUT) return [types.TextContent(type="text", text=json.dumps(error_response, indent=2))] except Exception as e: logger.error(f"Unexpected error: {e}") error_response = sanitize_error(e, ERROR_GENERIC) return [types.TextContent(type="text", text=json.dumps(error_response, indent=2))]
• src/mcp_gitlab/constants.py:223-223 (helper)

  Constant defining the exact tool name string used throughout the codebase for references, mappings, and schema definitions.
  TOOL_GET_MR_CHANGES = "gitlab_get_merge_request_changes"