MCP-TY

Instructions

Implementation Reference

• src/mcp_ty/server.py:669-724 (handler)

  The 'apply_code_action' tool is defined as an MCP tool and handles applying code actions to files using an LSP client.

  @mcp.tool()
  async def apply_code_action(
      file_path: str, line: int, column: int, action_index: int
  ) -> str:
      """Apply a code action by index (from get_code_actions)."""
      client = _get_client()
  
      path = Path(file_path).resolve()
      if not path.exists():
          return _error(f"File not found: {file_path}")
  
      try:
          await client.open_document(path)
  
          import asyncio
          await asyncio.sleep(0.3)
  
          diagnostics = client.get_diagnostics(path)
          relevant_diags = [
              d for d in diagnostics
              if d.range.start.line <= line - 1 <= d.range.end.line
          ]
  
          actions = await client.get_code_actions(
              path, line - 1, column - 1, line - 1, column, relevant_diags
          )
  
          if not actions:
              return _not_found(f"No actions at {path.name}:{line}:{column}")
  
          if action_index < 1 or action_index > len(actions):
              return _error(f"Invalid index. Choose 1-{len(actions)}")
  
          action = actions[action_index - 1]
  
          if not action.edit:
              return _error(f"Action '{action.title}' has no edits")
  
          all_edits = action.edit.get_all_edits()
          applied_files = []
  
          for uri, edits in all_edits.items():
              file_to_edit = _uri_to_path(uri)
              if file_to_edit.exists():
                  new_content = _apply_edits_to_file(file_to_edit, edits)
                  file_to_edit.write_text(new_content, encoding="utf-8")
                  applied_files.append(file_to_edit.name)
  
          return _ok({
              "applied": True,
              "action": action.title,
              "modified_files": applied_files
          })
  
      except Exception as e:
          return _error(str(e))