{
  "task_id": "L26",
  "title": "Versioned receipt hash test vectors for cross-language verification",
  "repo": "tessera",
  "kind": "build",
  "effect_class": "write-repo",
  "owner_type": "muse-code",
  "done_when": "make check passes with tests verifying every vector in conformance-draft/receipt_vectors.json against tessera.receipts.receipt_hash and canonical_json",
  "context": [
    "AGENTS.md",
    "conformance-draft/SPEC.md",
    "src/tessera/receipts.py",
    "tests/test_service.py"
  ],
  "constraints": [
    "Read AGENTS.md first; the spec wins over the code",
    "Never edit conformance/ or conformance.lock, and never weaken an existing test",
    "Include schema_version, spec_section, and cases covering nested keys, UTF-8 text, nulls, booleans, fractions, whole floats (1.0 -> 1 below 2^53), empty collections, and failed submits with error strings",
    "Keep src/tessera/ 100% domain-neutral",
    "No key, token or credential in any response, page, log or commit",
    "Run make check before committing; one task per branch; do not push"
  ],
  "budget": {
    "max_model_steps": 200,
    "usd": 1.5
  },
  "depends_on": [
    "L8"
  ],
  "branch": "t/L26-receipt-vectors",
  "notes": "Each vector stores input (task_id, fencing_token, ok, output, error), canonical_json and expected sha256 so JavaScript and TypeScript clients can verify SHA-256 receipts byte-for-byte."
}