Velaru Standards · Counterfactual Evidence · v1.0

TCB — Temporal Causal Binding

IETF draft-noa-scitt-ai-agent-receipt-00 leaves policy-replay out of scope. TCB fills that gap: a Counterfactual Receipt (CCR) cryptographically bound to a frozen Handler Receipt, answering what would have happened under the committed policy.

Counterfactual Receipt (CCR) Handler Receipt binding Type III negative attestation Verify CHECK 9 POSS-2 Causal tier

The primitive

A CCR attests that a specific represented path was available within the observation boundary, cryptographically sealed, and not selected as the final path — enabling audit of rejected alternatives in EPL and carrier disputes.

CCR = Sign( source_entry ‖ handler_receipt ‖ counterfactual_digest ‖ intervention )

API

POST https://velaru.onrender.com/tcb/counterfactual-replay
Content-Type: application/json

{
  "entry_id": "SOURCE_RECEIPT_HASH",
  "session_id": "pilot-1"
}

→ 200 { "ccr_id", "causal_binding_hash", "counterfactual_reply",
         "handler_receipt_id", "verify_url", "signature" }

GET https://velaru.onrender.com/tcb/ccr/{ccr_id}/verify.json
→ portable CCR receipt for /verify

Causal binding flow

1. Handler Receipt frozen in registry (pre-incident policy commitment)
2. Classify issues signed receipt for actual outcome (GEN/DENY/ERROR/SILENCE)
3. TCB replays counterfactual path — what the model would have produced without block
4. CCR binds source + handler + counterfactual digest into signed chain entry
5. Carrier export includes CCR in Pre-Dispute Temporal Bundle pack

IETF SCITT companion (WIP)

draft-noa-scitt-ai-agent-receipt leaves policy-replay out of scope (§9). TCB is the companion profile for offline counterfactual binding under a frozen Handler Receipt.

Download companion draft (txt) · Found Scripture template

Verification

/verify runs CHECK 9 — TCB CAUSAL BINDING when bound_ccr_id or CCR receipt type is present. Recomputes causal_binding_hash from source + handler + digest.

Integration curl examples → POSS-2 architecture → Handler Receipt registry →