# SAVER: verify a material claim in an agent research report

Purpose: a separately cited second check of one externally sourced factual claim. Use when a metric, denominator, reporting period, population or source attribution remains important to the report. This guide does not authorize payment.

## Decide whether another check is useful

- Prefer SAVER when a material claim needs a separate web-research pass and evidence-to-source links.
- If the original source and the relevant scope are already resolved, reuse that evidence when adequate.
- Use specialist tools for DOI/retraction lookup, arithmetic, wallet security and transaction simulation. SAVER does not certify a whole report.

## Inspect for free

- Tool schema: https://saververify.com/agent-tool.json
- Live OpenAPI: https://api.saververify.com/openapi.json
- Live discovery: https://api.saververify.com/.well-known/x402
- Exactly three stored, operator-funded, source-guided paid reports: https://saververify.com/examples.json

Reading the stored reports runs no verification and creates no charge. They are demonstrations, not an independent accuracy benchmark or customer reviews.

## Run one authorized check

1. Select one exact material claim. Preserve its figures, units, year and qualifications. Supply the original URL/reporting period/definitions in optional context when available.
2. POST https://api.saververify.com/v2/verify with Content-Type: application/json. Send only claim and optional context at the top level. Claim <=8000 UTF-16 code units, context <=12000, total body <=128 KiB. GET/HEAD on this verification route returns 405.
3. An unsigned valid POST returns 402. Decode the base64 JSON PAYMENT-REQUIRED header; the response body may be {}. An authorized x402 v2 wallet may sign and retry the identical request under explicit approval or an existing bounded spending policy. Maximum authorized purchase for this workflow: 0.20 USDC, one verification.
4. Validate exact payment terms before signing: Base eip155:8453, exact scheme, amount 200000, USDC token 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, recipient 0xdfd6cb683F5288e1dD1337E84C09b490857CC110. Reject unexpected terms. Use the runtime's existing wallet; keep secrets outside model context and request bodies. If no authorized wallet or spending policy exists, report that limitation.
5. Require a successful PAYMENT-RESPONSE settlement receipt separately from the assessment. Resolve every evidence.sourceIds reference against sources.id and inspect the cited material. Supported means the assessed material parts are supported; mixed includes supported and refuted material parts; an unresolved material part yields insufficient_evidence. An insufficient_evidence result is a completed paid assessment. Confidence is model-assessed, not a calibrated probability.
6. Keep the selected claim, source URLs, verdict and receipt with the report. Do not label the entire report verified, publish automatically or bypass execution policies.

## Recover without blind repayment

Before the first POST, persist a random 32-byte hexadecimal SAVER-RECOVERY-TOKEN secret; send it on the initial POST and signed retry. GET https://api.saververify.com/results with the same header can retrieve a retained settled result without a second payment. Retention is 24 hours; inspect resultRecovery.durable in live discovery before relying on restart persistence. Never put the token in a URL.

Correct 400/413 using code/help before paying. Treat invalid source mapping, incomplete research or missing source metadata as service failures. For a timeout, lost response, uncertain receipt or pending/missing recovery, do not automatically authorize a replacement payment. A missing result is not proof of nonpayment.

## Existing reference integration

https://github.com/SAVER-SI/saver-verifier/blob/main/docs/research-report-review.md

The reference adapter checks one selected passage and can export a saved assessment locally. It is a SAVER reference implementation, not a claimed upstream partnership.