PyGithub MCP Server

Instructions

Args:
    params: Parameters for adding labels including:
        - owner: Repository owner (user or organization)
        - repo: Repository name
        - issue_number: Issue number
        - labels: Labels to add

Returns:
    Updated list of labels from GitHub API

Implementation Reference

• src/pygithub_mcp_server/tools/issues/tools.py:350-383 (handler)

  MCP tool handler decorated with @tool(). Validates input using AddIssueLabelsParams, delegates to operations.issues.add_issue_labels(), handles GitHub and unexpected errors, formats MCP-compatible response with JSON content or error.

  @tool()
  def add_issue_labels(params: AddIssueLabelsParams) -> dict:
      """Add labels to an issue.
      
      Args:
          params: Parameters for adding labels including:
              - owner: Repository owner (user or organization)
              - repo: Repository name
              - issue_number: Issue number
              - labels: Labels to add
      
      Returns:
          Updated list of labels from GitHub API
      """
      try:
          logger.debug(f"add_issue_labels called with params: {params}")
          # Pass the Pydantic model directly to the operation
          result = issues.add_issue_labels(params)
          logger.debug(f"Got result: {result}")
          return {"content": [{"type": "text", "text": json.dumps(result, indent=2)}]}
      except GitHubError as e:
          logger.error(f"GitHub error: {e}")
          return {
              "content": [{"type": "error", "text": format_github_error(e)}],
              "is_error": True
          }
      except Exception as e:
          logger.error(f"Unexpected error: {e}")
          logger.error(traceback.format_exc())
          error_msg = str(e) if str(e) else "An unexpected error occurred"
          return {
              "content": [{"type": "error", "text": f"Internal server error: {error_msg}"}],
              "is_error": True
          }

• src/pygithub_mcp_server/schemas/issues.py:328-343 (schema)

  Pydantic model defining input schema for add_issue_labels tool. Inherits from RepositoryRef (owner/repo), adds issue_number and labels list. Validates labels is non-empty.

  class AddIssueLabelsParams(RepositoryRef):
      """Parameters for adding labels to an issue."""
  
      model_config = ConfigDict(strict=True)
      
      issue_number: int = Field(..., description="Issue number")
      labels: List[str] = Field(..., description="Labels to add")
      
      @field_validator('labels')
      @classmethod
      def validate_labels(cls, v):
          """Validate that labels list is not empty."""
          if not v:
              raise ValueError("labels list cannot be empty")
          return v

• src/pygithub_mcp_server/tools/issues/tools.py:439-463 (registration)

  Registration function that adds add_issue_labels (line 457) along with other issue tools to the MCP server using register_tools.

  def register(mcp: FastMCP) -> None:
      """Register all issue tools with the MCP server.
      
      Args:
          mcp: The MCP server instance
      """
      from pygithub_mcp_server.tools import register_tools
      
      # List of all issue tools to register
      issue_tools = [
          create_issue,
          list_issues,
          get_issue,
          update_issue,
          add_issue_comment,
          list_issue_comments,
          update_issue_comment,
          delete_issue_comment,
          add_issue_labels,
          remove_issue_label,
      ]
      
      register_tools(mcp, issue_tools)
      logger.debug(f"Registered {len(issue_tools)} issue tools")

• src/pygithub_mcp_server/operations/issues.py:352-378 (helper)

  Helper function implementing GitHub API interaction: retrieves repo/issue, calls PyGithub issue.add_to_labels(*labels), fetches updated labels, converts and returns list.

  def add_issue_labels(params: AddIssueLabelsParams) -> List[Dict[str, Any]]:
      """Add labels to an issue.
  
      Args:
          params: Validated parameters for adding labels to an issue
  
      Returns:
          Updated list of labels from GitHub API
  
      Raises:
          GitHubError: If the API request fails
      """
      try:
          client = GitHubClient.get_instance()
          repository = client.get_repo(f"{params.owner}/{params.repo}")
          issue = repository.get_issue(params.issue_number)
  
          # Add labels to the issue
          issue.add_to_labels(*params.labels)
  
          # Get fresh issue data to get updated labels
          updated_issue = repository.get_issue(params.issue_number)
          return [convert_label(label) for label in updated_issue.labels]
  
      except GithubException as e:
          raise GitHubClient.get_instance()._handle_github_exception(e)