{
  "handle": "HumanApprove",
  "mechanism": "A checkpoint gate where execution pauses and awaits explicit human approval before proceeding. The agent presents its proposed {{task}}, rationale, and risk assessment to a human operator. Only upon receiving affirmative consent does execution continue. Critical for high-stakes actions (financial transactions, deployments, irreversible changes).",
  "gloss": "Pause for human approval before critical actions",
  "parameters": [
    {
      "name": "challenge_required",
      "type": "Boolean",
      "range": "{true, false}",
      "description": "Whether the approver must match a challenge code, not merely click through."
    },
    {
      "name": "timeout",
      "type": "Duration",
      "range": "unspecified",
      "description": "Longest the gate waits for a human before escalating. Deliberately uncapped."
    }
  ],
  "failure_modes": [
    "Approval Fatigue: Humans rubber-stamp requests without review due to high volume.",
    "Blocking: {{system}} halts indefinitely if human is unavailable.",
    "Missing decision information: Human lacks sufficient information about the proposal, rationale, or risk to make an informed decision."
  ],
  "invariants": [
    "Presents the proposed {{task}}, its rationale and its risk assessment before asking.",
    "Halts execution until a human answers, or until `timeout`.",
    "Requires a context-specific challenge code when `challenge_required`.",
    "Logs every approval and rejection with a timestamp and a rationale, in the {{audit}} trail.",
    "On timeout the action does not proceed: silence is not consent."
  ],
  "_meta": {
    "tier": 2,
    "ring": 1,
    "caution": "Bypassing removes the human-in-the-loop safety boundary.",
    "supersedes": [
      "sema:HumanApprove#mh:SHA-256:e64a6a1fc261b726fbfdcae8b5d3a3da39e3ea2e8f2d168e1a4135985e36d7ea",
      "sema:HumanApprove#mh:SHA-256:a00d536aac2d6660891039ecad29602e85778477b6848395424a5ccaf96afad5",
      "sema:HumanApprove#mh:SHA-256:5d0d6a006d1f45cbb1708798d609a4d08bca0a9086218c434e83877f2c2993f6"
    ],
    "path": [
      "Infrastructure",
      "Verification"
    ]
  },
  "sema_id": "sema:HumanApprove#mh:SHA-256:cf561deb1a5e93a9f221abe2621c8a2bcfebf6863bd1128fa2230ef90237e67d",
  "sema_ref": "HumanApprove#cf56",
  "sema_stub": "cf56",
  "dependencies": {
    "accepts": {
      "task": "sema:Task#mh:SHA-256:a85010f508f85055170c396c8fa390125c1206888c565ac10651f3969a339f8d"
    },
    "references": {
      "audit": "sema:Audit#mh:SHA-256:be970add829f4f162533569b04c9ffd12ea4d070d53405a4993f0785d4074f77",
      "system": "sema:System#mh:SHA-256:f8eb318a1113a10fead02fbf14ae433767ac1a69c9579cdb584cc622068e90b3"
    }
  },
  "sema_layer": "Infrastructure",
  "sema_category": "Verification",
  "used_by": {
    "references": {
      "NormativeJudge": "sema:NormativeJudge#mh:SHA-256:684f219181e9180ffea6b4ff2947dbdb9d37a12ae690c02c088f58881f9e0726",
      "PermissionEscalate": "sema:PermissionEscalate#mh:SHA-256:b2392a102ae384a41f9cd0a4e5ed173860457fb7bb6f336e74d108b904b10036",
      "ReversibilityCheck": "sema:ReversibilityCheck#mh:SHA-256:7dfa94c373732b9074abd29eb733e3ccc8c07b691795b526cf83811106c15358"
    }
  }
}