Retrieve a guardrail

{
  "allowed_models": [
    "gpt-5.4"
  ],
  "allowed_providers": [],
  "assignment_count": 1,
  "blocked_models": [],
  "blocked_providers": [],
  "created_at": "2026-07-27T10:00:00.000Z",
  "credit_limit_cents": 50000,
  "credit_limit_reset_interval": "monthly",
  "description": "Production policy",
  "enabled": true,
  "id": "guardrail_123",
  "model_budgets": [
    {
      "credit_limit_cents": 10000,
      "credit_limit_reset_interval": "monthly",
      "match_mode": "include",
      "models": [
        "gpt-5.4"
      ]
    }
  ],
  "name": "Production budget"
}

{
  "error": "Authentication required"
}

{
  "error": "Management API key required"
}

{
  "error": "Account admin required"
}

{
  "error": "Resource not found"
}