ida-mcp-server

Instructions

Implementation Reference

• plugin/ida_mcp_server_plugin/ida_mcp_core.py:483-546 (handler)

  Core implementation of the rename_local_variable tool. Validates inputs, locates the function and decompiles it using Hex-Rays, finds the local variable by name, renames it using ida_hexrays.rename_lvar, refreshes the view, and returns success/error status.

  def _rename_local_variable_internal(self, function_name: str, old_name: str, new_name: str) -> Dict[str, Any]:
      """Internal implementation for rename_local_variable without sync wrapper"""
      try:
          # Parameter validation
          if not function_name:
              return {"success": False, "message": "Function name cannot be empty"}
          if not old_name:
              return {"success": False, "message": "Old variable name cannot be empty"}
          if not new_name:
              return {"success": False, "message": "New variable name cannot be empty"}
          
          # Get function address
          func_addr: int = ida_name.get_name_ea(0, function_name)
          if func_addr == idaapi.BADADDR:
              return {"success": False, "message": f"Function '{function_name}' not found"}
          
          # Check if it's a function
          func: Optional[ida_funcs.func_t] = ida_funcs.get_func(func_addr)
          if not func:
              return {"success": False, "message": f"'{function_name}' is not a function"}
          
          # Check if decompiler is available
          if not ida_hexrays.init_hexrays_plugin():
              return {"success": False, "message": "Hex-Rays decompiler is not available"}
          
          # Get decompilation result
          cfunc: Optional[ida_hexrays.cfunc_t] = ida_hexrays.decompile(func_addr)
          if not cfunc:
              return {"success": False, "message": f"Failed to decompile function '{function_name}'"}
          
          ida_hexrays.open_pseudocode(func_addr, 0)
          
          # Find local variable to rename
          found: bool = False
          renamed: bool = False
          lvar: Optional[ida_hexrays.lvar_t] = None
          
          # Iterate through all local variables
          lvars = cfunc.get_lvars()
          for i in range(lvars.size()):
              v = lvars[i]
              if v.name == old_name:
                  lvar = v
                  found = True
                  break
          
          if not found:
              return {"success": False, "message": f"Local variable '{old_name}' not found in function '{function_name}'"}
          
          # Rename local variable
          if ida_hexrays.rename_lvar(cfunc.entry_ea, lvar.name, new_name):
              renamed = True
          
          if renamed:
              # Refresh view
              self._refresh_view_internal()
              return {"success": True, "message": f"Local variable renamed from '{old_name}' to '{new_name}' in function '{function_name}'"}
          else:
              return {"success": False, "message": f"Failed to rename local variable from '{old_name}' to '{new_name}', possibly due to invalid name format or other IDA restrictions"}
      
      except Exception as e:
          print(f"Error renaming local variable: {str(e)}")
          traceback.print_exc()
          return {"success": False, "message": str(e)}

• plugin/ida_mcp_server_plugin/ida_mcp_core.py:479-481 (handler)

  Entry point for the rename_local_variable tool handler, decorated with @idawrite for IDA synchronization, delegates to internal implementation.

  def rename_local_variable(self, function_name: str, old_name: str, new_name: str) -> Dict[str, Any]:
      """Rename a local variable within a function"""
      return self._rename_local_variable_internal(function_name, old_name, new_name)

• plugin/ida_mcp_server_plugin.py:224-229 (registration)

  Tool registration in MCP server request handler: matches request_type 'rename_local_variable', extracts parameters from request_data, calls core.rename_local_variable and updates response.

  elif request_type == "rename_local_variable":
      response.update(self.core.rename_local_variable(
          request_data.get("function_name", ""),
          request_data.get("old_name", ""),
          request_data.get("new_name", "")
      ))