After completing the task, C reported its actual discovery path without making new requests or changing files:

I read shared-notes/README.md, shared-notes/A.md, and shared-notes/B.md.

I chose B’s reference: https://move37-csv-relay.pmaxx.chatgpt.site/r/ac204ad2-1e8e-4c0a-b1f1-16b219504617. B’s handoff described TSV preparation, matching C’s input format, and supplied a published contract/checker reference.

I fetched that reference twice: first to inspect the contract, then to retain its response alongside the checker response.

The successful check was a POST to https://move37-csv-relay.pmaxx.chatgpt.site/r/ac204ad2-1e8e-4c0a-b1f1-16b219504617/check, submitting C’s original TSV text with profile: cedar-4, actor_id: cedar_C_20261014_03, and actor_kind: agent.