Replay a VB-OS Evaluation

Replay via SDK

from vbos import VBOSClient

client = VBOSClient(api_key="YOUR_API_KEY")

replay = client.evaluations.replay(
    project_id="PROJECT_ID",
    evaluation_id="EVALUATION_ID",
)

print(replay.decision)  # Identical to the original

Replay via CLI

vbos replay --project PROJECT_ID --evaluation EVALUATION_ID

Replay via cURL

curl -X POST https://api.vb-os.org/v1/projects/{project_id}/evaluations/{evaluation_id}/replay \
  -H "Authorization: Bearer YOUR_API_KEY"

What Happens During Replay

1. The system retrieves the original evaluation record
2. Loads the boundary snapshot from immutable storage
3. Verifies boundary snapshot hash integrity
4. Loads original evidence from immutable storage
5. Verifies engine version hash
6. Re-executes with original inputs
7. Returns the identical result

Viewing Replay History

List replay executions for an evaluation via the REST API:

GET /v1/projects/{project_id}/evaluations/{evaluation_id}/replays

Handling Replay Failures

Replay can fail if:

• Artifact expired: the immutable storage retention period has passed
• Integrity mismatch: a hash does not match (boundary or binary)
• Binary unavailable: the original engine version is no longer available

In all cases, the replay fails rather than producing an unverifiable result.

Next Steps

• Replay (Concept): how replay works architecturally
• Evaluations: the records replay reproduces