Replay

Replay re-executes a historical evaluation using the original evidence and the original boundary snapshot from immutable storage. The result proves that the same inputs produce the same verdict, regardless of when the replay occurs.

Running a Replay

From any evaluation detail page, click Replay. VB-OS loads the original evidence and boundary from cold storage, re-runs the evaluation, and compares the result to the original verdict.

The replay result shows:

• The original verdict and the replayed verdict (these should match)
• Whether the result matched (result_match)
• The original evaluation ID
• The boundary snapshot hash (proving the same compiled boundary was used)
• A timestamp for when the replay was executed

Why Replay Matters

Replay provides cryptographic proof that a governance decision can be audited and reproduced. This is not a “best effort” feature. If the evidence artifact exists and the boundary snapshot exists, replay produces an identical result.

This means:

• Any decision can be audited months or years after it was made
• Regulators, auditors, or internal teams can independently verify that governance was applied correctly
• No one can claim a verdict was different from what actually happened

Replay verifies how VB-OS resolves a recorded decision from its preserved governance inputs. It does not reconstruct or depend on the current state of external systems that originally supplied evidence. The evidence used in replay is the evidence that was captured and stored at the time of the original evaluation.

Conformance Re-evaluation

When the original binary version is unavailable (for example, after a binary upgrade), VB-OS performs a conformance re-evaluation: the replay runs against the current binary version. The result_match field tracks whether the outcome is consistent with the original. A mismatch does not indicate an error in the original evaluation. It indicates a behavioral difference between binary versions that requires investigation.

What’s Next

• Evaluations : run new evaluations against deployed boundaries
• Certifications : run multi-evaluation certification models with audit-ready evidence chains