Hey, thanks for the report. This is actually expected behavior in Cursor 2.0: the @Code and @Definitions features were removed as part of the context menu changes. The Agent now gathers the needed context on its own without manual symbol references.
Workaround: reference the file that contains the interface (for example, @types.ts) and explicitly mention the interface name in your prompt.
This behavior is being tracked here: Typing @ in the composer no longer autocompletes / references project symbols