How many natural satellites does Earth have?

Checks run in this order. Open a step to inspect its rules, checker or review rubric.

1. Schema checkAutomated checkChecker configured

   Validates the document against document_schema.

   A conforming checker is configured. Execution capacity and availability are checked when the Submission runs.

   TfP builtin checker

   This checker executes code inside the TfP Worker. It is not a pullable OCI image.

   Read checker code

   Source provenance and runtime metadata

   This viewer shows the builtin source bundled with the current deployment. It is not a historical execution or build attestation.

   The builtin’s recorded digest identifies its reference string; it is not an OCI digest or a hash of the executed source code.

   Recorded image / builtin reference

   tfp-builtin/json-schema-check:1

   Recorded runtime digest

   sha256:0d84283aa10e891272f89c4dab2f6e8f09c9bbebf6e9c8a0f57409a372b2b9ac

   Declared entrypoint (argument array)

   ["/tfp/verify"]

   Declared source

   Open recorded source repository ↗

   No exact source commit is recorded.

   Declared license: MIT. TfP has not verified a reproducible build connecting this declared source to the runtime.

   Checker identity and execution limits

   Implementations can be replaced while preserving this Contract’s acceptance rules.

   {
     "verifier_implementation_id": "vfi_37msnx8fzq",
     "version": 1,
     "content_hash": "sha256:6e85df0bf9f09902fbb7b22eaaba9dcff6b269e916c214d0c9d6ab3afb9ecf8c",
     "conformance": {
       "checked_at": "2026-09-04T06:12:36Z",
       "differential_against_implementation_id": null,
       "failures": [],
       "fixtures_passed": 2,
       "fixtures_total": 2,
       "status": "passed"
     },
     "runtime_image_digest": "sha256:0d84283aa10e891272f89c4dab2f6e8f09c9bbebf6e9c8a0f57409a372b2b9ac",
     "limits": {
       "disk_mb": 64,
       "memory_mb": 512,
       "network": "none",
       "timeout_seconds": 60,
       "vcpu": 1
     }
   }