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Evidence Events

Evidence events explain what the agent did under a mandate and why the runtime allowed, denied, or escalated the step.

The canonical schema is:

schemas/evidence-event.schema.json

Event Principles

  • Append evidence for material negotiation steps, disclosures, refusals, escalations, and commitments.
  • Store summaries and hashes instead of raw private content by default.
  • Include downstream protocol references when an action reached another system.
  • Keep evidence access controlled because even summaries can reveal preference and negotiation strategy.

Minimal Event Shape

{
  "aump": {
    "version": "0.1.0",
    "type": "evidence_event"
  },
  "id": "aump_ev_deal_accepted_001",
  "mandate_ref": {
    "id": "aump_mnd_market_buyer_001",
    "hash": "sha256-e27c2259f3135f02e1803950caacd8a28504b06ef47c081844e068199dee8c52",
    "version": "0.1.0"
  },
  "sequence": 1,
  "created_at": "2026-04-25T18:00:00Z",
  "event_type": "deal_accepted",
  "summary": "Accepted 19 ping pong balls for 3 USD after AUMP evaluation returned allowed.",
  "result": "allowed",
  "actor": {
    "role": "runtime",
    "id": "example-marketplace-runtime"
  },
  "reason_codes": [],
  "downstream_refs": [
    {
      "protocol": "mcp",
      "id": "call_1"
    }
  ],
  "privacy": {
    "retention": "hashes",
    "contains_private_fields": false,
    "redaction": "hash"
  }
}
Field Purpose
id Stable event identifier.
mandate_ref.id Mandate used for the decision.
mandate_ref.hash Integrity binding to the private mandate.
event_type Kind of action or decision.
result allowed, requires_escalation, denied, received, recorded, or error.
reason_codes Deterministic reasons.
action.hash Hash of proposed action payload.
downstream_refs Protocol-specific IDs.
created_at Timestamp.
privacy.contains_private_fields Whether the event retains protected data.

Semantic Checks

Conformance now validates more than shape:

  • mandate_ref.id must match the mandate being evaluated;
  • mandate_ref.hash must match the mandate payload;
  • event_type must be required by the mandate evidence policy;
  • privacy.retention must match the mandate evidence retention mode;
  • private fields are rejected unless the mandate explicitly allows full_transcript retention.

Evidence and Privacy

Evidence is not a dumping ground for prompts. Runtimes should avoid storing raw LLM chain-of-thought, private user notes, payment credentials, or protected reservation values unless a separate policy explicitly requires it.