Groundcheck

Gold402 Verified. Hand-reviewed and on the curated list — curation is the bar.

Claim grounding and delivery attestation for AI agents: machine-verified verdicts (supported/refuted/unverified) with confidence scores and cited sources, plus signed offline-verifiable receipts binding an x402 payment to what was delivered. Free single-claim tier; paid endpoints $0.005–$0.05 USDC on Base. ([OpenAPI](https://groundcheck.seiche.info/openapi.json)) ([npm](https://www.npmjs.com/package/groundcheck-mcp))