Governed & Auditable Agent Messaging

Policy on the message path. Every step in an append-only ledger.

The problem

When an agent lives in a chat channel, three questions come up fast:

• What happened? — A user reports a bad response. You need to reconstruct the exact sequence: what was sent, what policy applied, which agent handled it, what was delivered.
• What should be blocked? — Compliance needs certain content filtered before it reaches the agent or before the agent's response reaches users.
• Can we prove it? — Audit requires a tamper-evident record of every message path outcome, including denied and failed deliveries.

Scattered logs across chat platform APIs, agent runtimes, and custom middleware cannot answer these questions reliably.

How CAR solves it

Canonical 7-event chain

Every message produces a complete event chain in the ledger:

message.received          ← inbound message canonicalized
  → policy.decision.made  ← governance verdict (allow / deny)
  → route.decision.made   ← which agent handles this
  → agent.invocation.requested
  → agent.response.completed
  → message.send.requested
  → message.sent          ← delivery confirmed

If denied or failed:
  → event.blocked         ← reason, stage, and context preserved

Every event carries correlation_id and causation_id, linking the full causal chain. The ledger is append-only — events are never modified or deleted.

Inbound and outbound policy

Define policy rules in YAML. CAR evaluates them on the message path before routing (inbound) and before delivery (outbound):

rules:
  - name: block-sensitive-keywords
    match:
      keywords: ["SSN", "credit card", "password"]
    action: deny
    reason: "Sensitive content detected"

  - name: allow-support-channel
    match:
      channel_pattern: "support-*"
    action: allow

Blocked messages produce event.blocked in the ledger with the denial reason — the outcome is auditable, not silent.

Replay and query

The HTTP API exposes the ledger for querying:

$ curl http://localhost:3000/api/conversations/conv_abc/events
[
  { "type": "message.received", "correlation_id": "req_123", ... },
  { "type": "policy.decision.made", "payload": { "decision": "allow" }, ... },
  { "type": "route.decision.made", ... },
  { "type": "agent.invocation.requested", ... },
  { "type": "agent.response.completed", ... },
  { "type": "message.send.requested", ... },
  { "type": "message.sent", ... }
]

What you get