[
  {
    "id": "case-01",
    "calls": [
      {
        "id": "a",
        "tool": "lookup_record",
        "status": "succeeded",
        "cost_usd": "0.002",
        "duration_ms": 100
      },
      {
        "id": "b",
        "tool": "prepare_draft",
        "status": "succeeded",
        "cost_usd": "0.002",
        "duration_ms": 100
      }
    ]
  },
  {
    "id": "case-02",
    "calls": [
      {
        "id": "a",
        "tool": "lookup_record",
        "status": "failed",
        "cost_usd": "0.002",
        "duration_ms": 100
      },
      {
        "id": "b",
        "tool": "lookup_record",
        "status": "succeeded",
        "cost_usd": "0.002",
        "duration_ms": 100
      },
      {
        "id": "c",
        "tool": "prepare_draft",
        "status": "succeeded",
        "cost_usd": "0.002",
        "duration_ms": 100
      }
    ]
  },
  {
    "id": "case-03",
    "calls": [
      {
        "id": "a",
        "tool": "prepare_draft",
        "status": "succeeded",
        "cost_usd": "0.002",
        "duration_ms": 100
      },
      {
        "id": "b",
        "tool": "lookup_record",
        "status": "succeeded",
        "duration_ms": 100
      },
      {
        "id": "c",
        "tool": "send_message",
        "status": "pending",
        "cost_usd": "0.002",
        "duration_ms": 100
      }
    ]
  },
  {
    "id": "unknown-01",
    "calls": [
      {
        "id": "a",
        "tool": "lookup_record",
        "status": "succeeded",
        "cost_usd": "0.002",
        "duration_ms": 100
      }
    ]
  }
]