Check an agent's log without taking the operator's word for it.

A witness receipt is Headless Oracle's signed statement of what it was shown and when: at received_at, a checkpoint signed by the key with that thumbprint. It is only as reliable as Headless Oracle and its signing key. It does not prove that the records are true, who controls the key, or that the records were written at the times they carry.

• Entries after the last witnessed checkpoint can still be cut off or rewritten without detection.
• A history rewritten before it was first witnessed is not detected. The gap between an entry's time and received_at is that exposure window.
• A session the operator never presents, or one restarted under a new key or session ID, starts with no receipts.
• Witness is independent of the operator, not of Headless Oracle, which also publishes the gate.
• Receipts are signed one by one, but the list of them is not: a mirror, proxy or modified client can leave receipts out. Query Witness directly.

The full list is in the Witness spec, under honest_limits.

Every entry in a Chirindo log carries the operator key's thumbprint (kid) and the session_id. Ask Witness for every receipt it holds for that pair. The query is public, needs no account, and answers any origin.

The answer is { "kid", "session_id", "receipts": [...], "next_after" }: at most 500 receipts ordered by count. If next_after is present, ask again with &after= set to it, and keep going until it is absent. A pair Witness has never seen returns an empty list, not an error.

To try it on the demo log from the homepage:

Check each receipt's signature

A receipt is signed by Headless Oracle with Ed25519 over all its fields except signature, keys sorted, as JSON with no whitespace; the signature is lowercase hex. Take the public key from api.headlessoracle.com/v5/keys: the keys[] entry whose key_id equals the receipt's public_key_id (currently key_2026_v1). Pin it: after a key rotation, the endpoint lists only the new key.

Then check the receipt names the checkpoint: the same kid, session_id, count and last_entry_hash, and checkpoint_sha256 equal to the SHA-256 of the signed checkpoint. Finally, the log's entry at that count must hash to that last_entry_hash.