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Agent Payment Error Corpus - Error Families Diagnosis
x402
Agent Payment Error Corpus - Error Families Diagnosis is a paid API for AI agents from agent-payment-error-corpus.mtree.workers.dev, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).
Returns a machine-readable corpus of agent payment error families with provenance and route-specific evidence to help autonomous agents diagnose payment failures
Price / call$0.05
Success—
StatusUnknown
How this service works
Paid agent payment error diagnosis route for autonomous agents. Returns JSON with provenance, route-specific evidence, and machine-readable fields. Price 0.05 USDC on Base via x402. Demo/preview: https://agent-payment-error-corpus.mtree.workers.dev/demo/error_families. Contact: https://agent-payment-error-corpus.mtree.workers.dev/contact.
Output
A JSON object containing a structured corpus of payment error families, each with provenance metadata, route-specific evidence, and machine-readable fields that categorize and explain common agent payment failure modes for x402/Base/USDC transactions.
Example use cases
Example prompt
“My autonomous agent is hitting payment errors on Base USDC transactions via x402 — can you pull the error families corpus so I can diagnose which error category we're dealing with and get the provenance and route-specific evidence for it?”
Technical details
Endpoint
POSThttps://agent-payment-error-corpus.mtree.workers.dev/v1/agent-payments/error_familiesWhen to prefer
Choose this endpoint when an autonomous agent needs to programmatically diagnose or classify payment errors in x402/Base/USDC agentic payment flows, especially when structured provenance and machine-readable error family data are required for automated error handling or debugging pipelines.
Side effects
- Payment not made or invalid x402 payment header — returns 402 Payment Required
- Malformed POST body — returns 400 Bad Request
- Service unavailable — returns 503
- Invalid route or endpoint — returns 404
- Payment underpaid (less than 0.05 USDC) — returns 402 with payment details
Input
{
"input": {
"body": {
"protocol": "x402"
},
"type": "http",
"method": "POST",
"bodyType": "json"
}
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
{
"ok": true,
"rows": [
{
"id": "insufficient_usdc",
"family": "payer_balance_allowance",
"protocol": "x402",
"severity": "medium",
"last_seen": "2026-06-03T22:31:37.000Z",
"root_cause": "Payer wallet lacks USDC on the requested network or is funding a different chain/account than the payment requirement",
"source_url": "https://docs.cdp.coinbase.com/x402/",
"remediation": "Check balance on the exact network and USDC asset in accepts[], bridge/fund the payer, then regenerate the payment payload",
"surface_signal": "insufficient USDC, balance too low, transfer amount exceeds balance, allowance/funds unavailable"
},
{
"id": "facilitator_rpc_retryable",
"family": "facilitator_or_rpc_outage",
"protocol": "x402",
"severity": "medium",
"last_seen": "2026-06-03T22:31:37.000Z",
"root_cause": "Payment facilitator or underlying RPC is degraded but surfaced to the agent as a generic payment failure",
"source_url": "https://docs.cdp.coinbase.com/x402/",
"remediation": "Classify as retryable infrastructure failure, back off with jitter, preserve payment attempt IDs, and show facilitator/RPC status separately from user-payment errors",
"surface_signal": "facilitator unavailable, RPC timeout, 5xx, network error, retryable 402, settle/verify timeout"
},
{
"id": "x402_retry_loop",
"family": "retry_loop",
"protocol": "x402",
"severity": "high",
"last_seen": "2026-06-03T22:31:37.000Z",
"root_cause": "Client is not persisting the new payment payload, signs for the wrong resource, or facilitator verification failure is collapsed into another 402",
"source_url": "https://docs.x402.org/",
"remediation": "Rebuild the X-PAYMENT payload for the exact method+URL+body, stop automatic blind retries, log facilitator verify response separately from app authorization, and surface one actionable 4xx to the caller",
"surface_signal": "Repeated 402 responses after X-PAYMENT is supplied; client retries same paid request"
},
{
"id": "eip3009_expired_signature",
"family": "authorization_time_window",
"protocol": "x402",
"severity": "high",
"last_seen": "2026-06-03T22:31:37.000Z",
"root_cause": "EIP-3009 TransferWithAuthorization validity window does not include facilitator verification time",
"source_url": "https://eips.ethereum.org/EIPS/eip-3009",
"remediation": "Sync clocks, use short but realistic validity windows, regenerate authorization near request time, and include validAfter/validBefore in debug logs",
"surface_signal": "authorization expired, validBefore in the past, not yet valid, validAfter in the future, or clock skew"
},
{
"id": "eip712_chain_domain_mismatch",
"family": "signature_domain_mismatch",
"protocol": "x402",
"severity": "critical",
"last_seen": "2026-06-03T22:31:37.000Z",
"root_cause": "EIP-712 typed data was signed for a different chain/domain/resource than the server/facilitator verifies",
"source_url": "https://eips.ethereum.org/EIPS/eip-712",
"remediation": "Derive chainId/network/payTo/resource from the server payment requirements; do not reuse cached typed-data across chains or hosts",
"surface_signal": "invalid signature, bad domain separator, chainId mismatch, verifyingContract mismatch, or resource host mismatch"
},
{
"id": "eip3009_reused_nonce",
"family": "nonce_idempotency_conflict",
"protocol": "x402",
"severity": "critical",
"last_seen": "2026-06-03T22:31:37.000Z",
"root_cause": "A one-time EIP-3009 nonce/payment authorization was reused across retries or concurrent workers",
"source_url": "https://eips.ethereum.org/EIPS/eip-3009",
"remediation": "Generate a fresh nonce per paid attempt, store idempotency keys separately from payment nonces, and never replay settled/verified authorizations",
"surface_signal": "authorization already used, nonce consumed, duplicate payment, replay rejected, idempotency conflict"
}
],
"dataset": {
"fresh": true,
"protocols": [
{
"n": 6,
"protocol": "x402"
},
{
"n": 3,
"protocol": "AP2"
},
{
"n": 1,
"protocol": "ACP/MPP"
},
{
"n": 1,
"protocol": "MCP"
},
{
"n": 1,
"protocol": "TAP"
}
],
"severities": [
{
"n": 5,
"severity": "high"
},
{
"n": 4,
"severity": "medium"
},
{
"n": 3,
"severity": "critical"
}
],
"last_ingest": {
"id": 515,
"ok": 1,
"ts": 1780525897,
"error": "",
"iso_ts": "2026-06-03T22:31:37.000Z",
"source": "seeded-public-protocol-corpus",
"upserted": 12,
"attempted": 12
},
"dataset_fresh_at": "2026-06-03T22:31:37.000Z",
"total_signatures": 12
}
}Tags
x402
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