Action Receipts

Receipt Structure

An Action Receipt is a signed record of an action performed by an agent. Receipts form a tamper-evident, hash-chained log.

{
  "id": "rcpt_01HQ3P9LYCD8ZH3ENQWT6G7F0U",
  "version": "0.1.0",
  "timestamp": "2026-02-24T12:30:00.000Z",
  "agent": "did:idprova:example.com:kai-lead-agent",
  "delegation": "dat_01HQ3N8KXBC7YG2DMPVS5F6E9T",
  "action": {
    "type": "mcp:tool:filesystem:read",
    "target": "/projects/idprova/README.md",
    "method": "readFile",
    "parameters": {
      "path": "/projects/idprova/README.md",
      "encoding": "utf-8"
    },
    "result": {
      "status": "success",
      "bytesRead": 4096,
      "contentHash": "blake3:f8c3..."
    }
  },
  "context": {
    "sessionId": "sess_01HQ3P2KABC...",
    "parentReceiptId": "rcpt_01HQ3P8KXBC...",
    "traceId": "trace_01HQ3P1JABC...",
    "environment": "production",
    "runtimeVersion": "openclaw/v2.1"
  },
  "chain": {
    "previousHash": "blake3:7a8b9c0d1e2f...",
    "sequenceNumber": 42
  },
  "signature": {
    "algorithm": "hybrid-ed25519-mldsa65",
    "keyId": "did:idprova:example.com:kai-lead-agent#key-ed25519-1",
    "value": "z4sK7qN2vR8wX1yT5uP3mJ6nB9cF0dA..."
  }
}

Field Definitions

Field	Type	Required	Description
id	string	Yes	Unique receipt identifier. Format: rcpt_ + ULID.
version	string	Yes	IDProva protocol version.
timestamp	ISO 8601	Yes	When the action was performed. MUST include milliseconds.
agent	DID	Yes	DID of the agent that performed the action.
delegation	string	Yes	jti of the DAT that authorised this action.
action	object	Yes	Details of the action performed.
context	object	No	Contextual information about the action.
chain	object	Yes	Hash chain linkage.
signature	object	Yes	Cryptographic signature over the receipt.

Action Object

Field	Type	Required	Description
type	string	Yes	Scope string of the action (same grammar as DAT scopes).
target	string	Yes	The resource acted upon.
method	string	No	The specific method/function called.
parameters	object	No	Input parameters (sensitive values SHOULD be redacted).
result	object	Yes	Outcome of the action.
result.status	string	Yes	success, failure, or error.

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Hash Chain

Action Receipts form a hash chain for tamper detection. Each receipt includes the hash of the previous receipt and a monotonically increasing sequence number.

Chain Construction

Receipt[0]:
  chain.previousHash = BLAKE3("GENESIS:" + agent_did)
  chain.sequenceNumber = 0

Receipt[n]:
  chain.previousHash = BLAKE3(CanonicalJSON(Receipt[n-1]))
  chain.sequenceNumber = n

Canonical Serialization

The input to the hash function is the receipt serialized using JSON Canonicalization Scheme (JCS, RFC 8785), with the signature field removed:

HashInput(receipt):
  1. receipt_copy = DeepCopy(receipt)
  2. delete receipt_copy.signature
  3. canonical = JCS_Serialize(receipt_copy)
  4. return BLAKE3(canonical)

Genesis Receipt

The first receipt in a chain uses a deterministic genesis hash:

genesisHash = BLAKE3("GENESIS:" + agent_did)

This allows verifiers to identify the start of a chain without out-of-band information.

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Integrity Verification

Full Chain Verification

VerifyChain(receipts[]):
  1. Sort receipts by sequenceNumber ascending
  2. if receipts[0].chain.sequenceNumber != 0:
       return INVALID("chain does not start at genesis")
  3. expected_prev = BLAKE3("GENESIS:" + receipts[0].agent)
  4. for each receipt in receipts:
       a. if receipt.chain.previousHash != expected_prev:
            return INVALID("hash chain break at seq " + receipt.chain.sequenceNumber)
       b. if receipt.chain.sequenceNumber != expected_seq:
            return INVALID("sequence gap at " + expected_seq)
       c. agent_did = resolver.resolveDID(receipt.agent)
       d. if not VerifySignature(receipt, agent_did):
            return INVALID("invalid signature at seq " + receipt.chain.sequenceNumber)
       e. expected_prev = HashInput(receipt)
       f. expected_seq = receipt.chain.sequenceNumber + 1
  5. return VALID(length=len(receipts))

Partial Verification

Verifiers MAY verify a subset of the chain by accepting a trusted checkpoint (a known-good receipt hash and sequence number) and verifying only from that point forward.

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Compliance Mapping

Action Receipts satisfy existing compliance framework controls out of the box.

NIST 800-53 Rev. 5

Control	Receipt Field	Description
AU-2 (Auditable Events)	action.type	Every significant action produces a receipt
AU-3 (Content of Audit Records)	All fields	Who, what, when, where, outcome
AU-8 (Time Stamps)	timestamp	ISO 8601 with milliseconds
AU-9 (Protection of Audit Information)	chain.*, signature	Hash chaining + signatures
AU-10 (Non-repudiation)	signature	Agent signs with own key
AU-12 (Audit Record Generation)	agent, delegation	Automated on every action
IA-2 (Identification & Authentication)	agent, delegation	DID-based identity in every receipt
AC-6 (Least Privilege)	delegation.scope	Enforceable scoped permissions

Australian ISM

ISM Control	Receipt Field	Description
ISM-0585	agent, delegation	Identification of processes acting on data
ISM-0988	action.type, action.target	Logging of privileged actions
ISM-0580	chain.*, signature	Integrity of audit logs
ISM-1405	timestamp, context.sessionId	Centralised event logging
ISM-0859	context.environment	System configuration logging

SOC 2 Trust Services Criteria

Criteria	Receipt Field	Description
CC6.1	agent, delegation	Logical access security — identity of actor
CC6.2	delegation, action.type	Authorised scope of access
CC6.3	chain.*	Integrity of audit trail
CC7.2	action.result.status	Monitoring of system operations
CC8.1	context.runtimeVersion	Change management tracking

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Use Cases

Post-incident forensics: Walk the receipt chain backwards to trace exactly what happened, who authorised it, and when.

Real-time monitoring: Stream receipts to detect anomalies — unusual action frequency, actions outside normal scope, unexpected time patterns.

Compliance auditing: Map receipts directly to compliance controls. Assessors verify the chain and confirm control coverage.

Attribution: Trace any action back through the delegation chain to the authorising human principal. Complete accountability from action to human.

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Next Steps

• Protocol Bindings — How receipts are requested and returned over MCP, A2A, HTTP
• Cryptography — Signature algorithms used in receipts
• Audit (Concepts) — High-level audit trail overview