The Guardian endpoint POST /v1/acs lets an agent consult IdentArk about a proposed action before taking it. It takes a JSON-RPC request describing the action plus context (agent, user) and returns allow, deny, or modify.

Scope

Calling the Guardian requires acs:evaluate. This scope grants only the right to be judged — it gives an agent key no read access to org data. It's included in the invoke preset, so the key your agent already carries can call it.

Request

POST /v1/acs speaks JSON-RPC 2.0. The endpoint always responds 200; errors travel in the JSON-RPC error channel rather than the HTTP status.

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "evaluate",
  "params": {
    "action": { "tool": "db.query", "args": { "sql": "…" } },
    "context": {
      "agent": { "id": "agent_…" },
      "user":  { "id": "user_…" }
    }
  }
}

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "decision": "allow",
    "reason": "within policy",
    "risk_score": 12
  }
}