# Clearsigned Claim Verification

> Clearsigned Claim Verification is a paid API for AI agents from verify.clearsigned.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Submits a claim with evidence to receive a cryptographically signed, ledger-chained verification receipt with an Ed25519 signature

## Facts

- Endpoint: POST https://verify.clearsigned.com/verify/t1
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/clearsigned-claim-verification-ec85c82f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_g7hMFI0YWhXreo2xaQNka

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability clearsigned-claim-verification-ec85c82f -d '<json body>'
```

Example prompt: Submit this claim — 'Invoice #4821 was paid in full on 2024-11-15' — along with these two evidence items (the bank transfer screenshot and the signed PDF) to Clearsigned and get me a signed receipt I can verify offline against their public key.

## When to prefer this

Choose this endpoint when you need an impartial, cryptographically signed, offline-verifiable attestation of a claim backed by evidence — particularly when the verifier cannot or should not call back to a live API. Its flat, verdict-independent pricing and public ledger chaining make it suitable for dispute resolution, audit trails, compliance documentation, and content provenance use cases where neither party should be able to claim the verifier had a stake in the outcome.

## Known failure modes

- Missing or malformed claim field returns validation error
- Evidence array empty or malformed prevents receipt issuance
- Service downtime triggers refund eligibility per stated policy
- Signature verification failure when checked offline may indicate receipt tampering or wrong public key version
- Current mode label may reflect non-production/test mode, limiting legal weight of receipt

## How this service works

Clearsigned — the trust layer with no stake in the outcome. Submit {claim, evidence[]}, receive an Ed25519-SIGNED, evidence-bearing receipt (verify offline against GET /pubkey; every receipt is chained in the public ledger at GET /ledger/verify). Flat price, verdict-independent; refunds only for failure to deliver. Current mode is honestly labeled in each receipt.

## Output

An Ed25519-signed receipt containing the submitted claim, evidence references, a verdict label, a current-mode indicator, and a chain entry that can be independently verified offline using the public key from GET /pubkey or cross-checked on the public ledger via GET /ledger/verify. Receipt is verdict-independent (flat $0.01 USDC price regardless of outcome); refunds issued only if delivery fails.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "claim": {
   "type": "string",
   "description": "The claim to verify (max 10k chars)"
  },
  "evidence": {
   "type": "array",
   "items": {
    "type": "string"
   },
   "description": "Supporting material; admitted as secondary-tier evidence"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/clearsigned-claim-verification-ec85c82f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from verify.clearsigned.com](https://www.zero.xyz/host/verify.clearsigned.com/llms.txt)