A tool receipt and an observed result answer different questions.

Where receiving-system verification fits alongside traces, durable runtimes and connector tools.

A trace can describe a tool call: what the agent asked for, which arguments it supplied, and what the tool returned. That record is useful. It may still leave an unanswered question about the state now visible in the receiving system.

Verify starts with an explicit outcome contract and reads the destination to compare observable fields. It can complement your existing execution, authentication, logging and retry infrastructure. It does not replace the system that performs the original action.

The response contains a verdict, checked predicates, observed resource references, a timestamp and a recovery instruction. The evidence hash can detect a change relative to the payload; it is not a signature or a third-party attestation.

A correlation marker locates a candidate resource. It is not proof that one particular actor caused a change. Likewise, an issue matching the declared fields does not establish customer satisfaction or completion of a whole business process.

The practical integration is small: register before the write, include the marker, verify when the result is uncertain, and retain the observation alongside your workflow trace. Test that sequence against failure cases before relying on it in a live customer workflow.