hello_worker

hello_worker — Minimal Canonical WCP Worker

capability_id: cap.hello.greet worker_species_id: wrk.hello.greeter risk_tier: low

This is the simplest possible complete WCP worker. Use it as a template.

What it does

Accepts a name and returns a greeting. That is all.

Input

{
  "name": "Alice",
  "correlation_id": "550e8400-e29b-41d4-a716-446655440000",
  "tenant_id": "demo"
}

Output

{
  "status": "ok",
  "result": {
    "greeting": "Hello, Alice!",
    "name": "Alice",
    "worker_id": "org.example.hello-greeter"
  },
  "telemetry": [
    {
      "event_id": "evt.worker.executed.v1",
      "timestamp": "...",
      "correlation_id": "...",
      "worker_id": "org.example.hello-greeter",
      "capability_id": "cap.hello.greet",
      "status": "ok"
    }
  ],
  "evidence": [
    {
      "correlation_id": "...",
      "worker_id": "org.example.hello-greeter",
      "capability_id": "cap.hello.greet",
      "policy_decision": "ALLOW",
      "controls_verified": ["ctrl.obs.audit-log-append-only"],
      "artifact_hash": "sha256:..."
    }
  ]
}

Run directly

python worker.py '{"name": "Alice", "correlation_id": "abc-123", "tenant_id": "demo"}'

Enroll in the Hall

pyhall enroll registry_record.json --registry-dir /path/to/enrolled/

Key patterns this demonstrates

1. WorkerContext — routing context propagated from the Hall
2. WorkerResult — standard response envelope (status, result, telemetry, evidence)
3. Telemetry event — evt.worker.executed.v1 with correlation_id propagated
4. Evidence receipt — SHA-256 artifact hash proving what was executed
5. Never raise — all errors returned as WorkerResult with status="error"
6. Stdio mode — --stdio flag for MCP server integration