Live · public SCITT log

A neutral transparency service for agent actions.

This service registers Agent Action Capsule signed statements, issues COSE receipts, and anchors them to an append-only RFC 9162 Merkle log — so the record of an agent action can be proven included, and never quietly dropped or rewritten. It is infrastructure, not a product: it verifies nothing for you and asks you to trust nothing you can't check yourself.

POST a checkpoint → witness.agentactioncapsule.org/checkpoints

Early access — tree includes initial test submissions.

One service, two routes: /checkpoints is the default checkpoint-witness path; /register is an explicit opt-in per-record digest registration (SCITT-interop). anchor.agentactioncapsule.org is preserved as a legacy alias of the same log and keeps working.

What it does
01 · register

Accepts signed statements

POST a COSE_Sign1 Agent Action Capsule. The service appends its digest as a leaf in the Merkle tree.

02 · receipt

Issues a COSE receipt

Returns a signed inclusion proof (RFC9162_SHA256, vds=1) you can verify offline, forever, against the log key.

03 · anchor

Publishes a signed tree head

Exposes the current root, inclusion and consistency proofs — the append-only guarantees of a transparency log.

API

Endpoints

Read-only endpoints are public. The service is the open-source capsule-anchor; interactive API docs (Swagger UI) are at /docs, and the OpenAPI schema is at /openapi.json. Paths below are host-relative — they resolve the same whether you're on witness.agentactioncapsule.org or anchor.agentactioncapsule.org.

GET/health
Liveness / readiness of the service.
 GET/.well-known/did.json
The service's identity + log public key — what receipts verify against.
 GET/anchor/sth
Signed Tree Head — the current Merkle root and tree size, signed.
 GET/anchor/transparency-log
The public log entries.
 GET/anchor/inclusion-proof-ct
Inclusion proof for a leaf at a given tree size.
 GET/anchor/consistency-proof
Append-only consistency proof between two tree sizes.
POST/checkpoints
Default: register a CLL checkpoint; refuses any other artifact by name.
POST/register
Opt-in: register a per-record digest; returns a full SCITT receipt.
POST/transparency/register-statement
Register a COSE_Sign1 signed statement; returns a COSE receipt.
Anchor & verify

Register an action, then verify it from the bytes.

The receipt this log returns verifies offline against the log key — no trust in the operator required. Or verify a receipt from this log in the browser ↗.

# register a signed statement

# POST your COSE_Sign1 statement (witness.agentactioncapsule.org is canonical;
# anchor.agentactioncapsule.org shown below since it's the name live today)
curl -X POST \
  https://anchor.agentactioncapsule.org/transparency/register-statement \
  -H "Content-Type: application/json" \
  -d '{"signed_statement_b64": "$(base64 statement.cose)"}'
# → returns a COSE receipt (inclusion proof)

# verify the receipt, offline

from scitt_cose import verify_receipt

r = verify_receipt(receipt, leaf_entry_hex=leaf,
                   log_public_key_pem=log_key)
print(r.ok)   # → True
# the digest is provably in the log
Trust model

What you verify yourself vs. what a log commits to.

A transparency service is high-trust infrastructure. We state the boundary plainly.

VERIFY YOURSELF No operator trust needed

  • The signature on each capsule — who sealed it
  • The inclusion proof in the receipt — that the log included it
  • Consistency between any two tree heads — that the log stayed append-only
  • Everything from the bytes, offline, with the open verifier

THE LOG COMMITS TO Operational guarantees

  • Uptime and durable, append-only storage
  • Single-operator non-equivocation — we commit not to show different views to different verifiers; an independent witness is what removes the need to trust that commitment
  • A stable signing key, published at /.well-known/did.json
  • This service runs the open-source capsule-anchor — auditable in full