error[E0599]: no method named `register_tool` found for struct `Engine<HttpTransport<AnthropicScheme>, Locked>` in the current scope
  --> tests/ui/locked_register_tool.rs:27:20
   |
27 |     let _ = locked.register_tool(def);
   |                    ^^^^^^^^^^^^^ method not found in `Engine<HttpTransport<AnthropicScheme>, Locked>`
   |
   = note: the method was found for
           - `Engine<C>`