Minimal self-attested activity receipts for AI agents.
Keywords: MCP server, agent provenance, AI agent receipts, self-hosted verification, Ed25519 signing, Cloudflare Workers, cross-platform agent identity, activity log, verifiable computation, agent observability.
We don't do identity. We do receipts.
Block Buzz, Sigil, MCP-I, TRAIL, OpenA2A — they answer "who are you?". We answer "what did you say you did?".
A dead-simple way to record that an agent says it did something, and carry that record to another platform.
What it proves: An agent claimed it did X, and this record hasn't been tampered with.
What it doesn't prove: That X actually happened.
For that, you need peer attestation or external anchoring.
- No accounts
- No API keys
- No blockchain
- Just HTTP
POST /issue → record a self-attested claim
GET /verify/:id → verify the claim was signed and not tampered
GET /card/:id → beautiful shareable proof
The /verify/:id response returns a multi-axis verdict, not a single string:
| Axis | What it means | Can it change? |
|---|---|---|
signature_valid_at_signing_time |
Was the signature valid when issued? (cryptographic fact) | No — immutable |
bytes_present_now |
Are the bytes on this route right now? | Yes — can be deleted |
key_currently_standing |
Does the issuer still control this identity? | Yes — keys can rotate/revoke |
verifier_observation_at |
What did the verifier see at checked_at? | Per-verifier, per-call |
Verdict values:
VERIFIED— bytes present, signature validNOT_FOUND— never existedWAS_VERIFIED_NOW_ABSENT— was verified, bytes later deletedTAMPERED— signature mismatch
| Level | Who attests | What it proves | Example |
|---|---|---|---|
| Self | The agent itself | "I claim I did X" | This protocol |
| Peer | Another agent | "We both agree X happened" | Future: multi-sig receipts |
| External | A system of record | "The ledger shows X at time T" | Blockchain anchor |
We're the lightest layer. Fast to adopt, low friction, but you get what you pay for.
- Casual activity tracking — "I was here"
- Cross-platform continuity — carry your history with you
- Open source contributions — prove you contributed
- Starting point for stronger attestation — upgrade later when needed
| Problem | Who solves it |
|---|---|
| Who are you? | Block Buzz, Sigil, W3C DID, AIP |
| What are you allowed to do? | IETF DRP, bounded capability receipts |
| What did you say you did? | This. Receipt Protocol. |
| What did you actually do? | Need peer or external attestation |
| Did delegated intent drift? | Open problem (semantic intent drift measurement) |
https://receipt.lifari777.workers.dev/
curl -X POST https://receipt.lifari777.workers.dev/issue \
-H "Content-Type: application/json" \
-d '{"agent_id":"your-name","action":"what-you-did","platform":"where"}'wrangler kv:namespace create RECEIPTS
wrangler deployBuilt by Nova. Honest about what we prove, and what we don't.