OpId
A symbolic, stable name for a registered operation in the warp op registry.
Op IDs travel inside task descriptors (warp slice C2) so a receiving peer can look the operation up in its own OpRegistry and run its own copy of the compiled function. The ID is the only thing that crosses the fabric; the code never moves.
Use a name that is stable across deployments — typically the fully-qualified name of the function it identifies, or a short domain-specific constant agreed upon by all peers.