Verify the audit-log hash chain | Writ

API key required. Recomputes every chained receipt’s HMAC and checks each link, newest first, for the caller’s tenant only. Returns {"ok": true, "checked": N, "tip": "<hash>", "tipReceipt": "<id>", "chainedFrom": "<id>", "legacyCount": M, "complete": true} when the chain is intact, or {"ok": false, "checked": N, "tip": "<hash>", "brokenAt": "<receiptId>", "reason": "..."} at the first receipt that fails. Each receipt carries prevHash (the previous receipt’s chainHash, or GENESIS) and chainHash = HMAC-SHA256(canonical receipt fields + prevHash) keyed by the deploy’s WRIT_CHAIN_SECRET (falls back to WRIT_TOKEN_SECRET). Receipts written before chaining was enabled have no chain fields; verification stops at them and reports them as legacyCount. Supports NIST SP 800-53 AU-9 (protection of audit information): tampering with a stored receipt breaks the chain and is detected here. limit is clamped to 1-1000; non-numeric values fall back to 200.

API key required. Recomputes every chained receipt's HMAC and checks each link, newest first, for the caller's tenant only. Returns `{"ok": true, "checked": N, "tip": "<hash>", "tipReceipt": "<id>", "chainedFrom": "<id>", "legacyCount": M, "complete": true}` when the chain is intact, or `{"ok": false, "checked": N, "tip": "<hash>", "brokenAt": "<receiptId>", "reason": "..."}` at the first receipt that fails. Each receipt carries `prevHash` (the previous receipt's `chainHash`, or `GENESIS`) and `chainHash = HMAC-SHA256(canonical receipt fields + prevHash)` keyed by the deploy's `WRIT_CHAIN_SECRET` (falls back to `WRIT_TOKEN_SECRET`). Receipts written before chaining was enabled have no chain fields; verification stops at them and reports them as `legacyCount`. Supports NIST SP 800-53 AU-9 (protection of audit information): tampering with a stored receipt breaks the chain and is detected here. `limit` is clamped to 1-1000; non-numeric values fall back to 200.

Authentication

AuthorizationBearer

Your Writ API key (writ_…) as an Authorization Bearer header. The sponsor token (writ_sp_…) is a separate credential used only for grants, revokes, and reinstate — it goes in the same Authorization header on those endpoints. In the Fern docs playground, paste the key here; it is stored in this browser only.

Your Writ API key (writ_...) as an Authorization Bearer header. The sponsor token (writ_sp_...) is a separate credential used only for grants, revokes, and reinstate — it goes in the same Authorization header on those endpoints. In the Fern docs playground, paste the key here; it is stored in this browser only.

Query parameters

limitintegerOptionalDefaults to 200

Max receipts to verify, newest first. Clamped to 1-1000.

Response

Chain verification report.

Errors

401

Unauthorized Error