Phase 5.0A Tool Execution Evidence

This bounded prerequisite establishes one execution-outcome contract before a runtime-plugin protocol or generation manager exists.

Contract	Executable evidence
Mandatory effect/replay metadata	go test ./tool -run TestDefinitionRejectsMissingAndInvalidExecutionMetadata
Canonical capability set and fingerprint	go test ./tool -run TestDefinitionFingerprintCoversContractAndNormalizesCapabilities
Bounded correlated typed errors	go test ./tool -run TestExecutionErrorIsBoundedCorrelatedAndCancellationCompatible
Dispatcher fail-closed validation	`go test ./stage -run ’TestDispatcher(PreservesAndValidatesTypedExecutionFailures
Model-visible result versus infrastructure failure	go test ./agent -run TestEngineDistinguishesModelVisibleToolProblemsFromExecutionFailures
Generated composition compatibility	`go test ./internal/compositionacceptance -run ’TestComposition(GenerationIsDeterministicAndOwnershipGuarded
Repository commit gate	make verify on the exact committed tree

Negative coverage includes absent/unknown metadata, read-only mutation capabilities, invalid effect/replay pairs, duplicate capabilities, unsafe retry advice, uncertain read-only outcomes, wrong call IDs, untyped errors, simultaneous result/error returns, nested failures, wrapped or joined typed failures, oversized causes/siblings, and canceled causes. Accepted direct typed failures preserve their original cause chain. Agent tests also assert that the terminal tool-failure event retains bounded call ID, name, outcome, and retry correlation.

This evidence deliberately excludes plugin protocol messages, dynamic plan sources, generation leases, retry execution, and process-host behavior. Those remain later Phase 5 slices.