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Agent-Exec Handoff — Pay-Per-Use Agent Briefing Storage
x402
Agent-Exec Handoff — Pay-Per-Use Agent Briefing Storage is a paid API for AI agents from agent-exec.448c.net, paid per call via x402, $0.0053/call, status unknown (last checked 2026-10-13).
Stores a structured agent handoff briefing (done/not-done/in-flight state plus next action) and returns a UUID that a successor agent can use to resume work, billed per-call via x402 micropayment with no account required.
Price / call$0.0053
Success—
StatusUnknown
How this service works
Accountless, pay-per-use code execution for software agents: submit source code, get stdout, stderr and exit code back from an isolated, network-less sandbox. No account, no API key -- possession of valid payment is sufficient.
Output
Returns a JSON object with a UUID handoff_id (share this with the successor agent — it needs nothing else to retrieve the briefing), an expiresAt Unix millisecond timestamp after which the briefing is swept and returns 410 then 404, and a payment object containing the asset, payer wallet address, amount in atomic units, network, and on-chain transaction hash confirming the x402 micropayment.
Example use cases
Chaining agents across a long research task
“Create a handoff for the next agent: we've finished scraping all 50 conference websites (verified: 50 JSON files in the output bucket), haven't started the speaker deduplication yet, and the email normalizer is still running. Tell the successor to wait for the normalizer to finish before doing anything else.”
Overnight agent shift handover
“I need to hand off to the morning agent — mark 'database backup' as done (evidence: backup log shows 3.2 GB written at 02:14 UTC), leave 'send summary report' as not done, and set pickUpFirst to 'send the daily summary email to the ops team'.”
Parallel agent task splitting
“Save a handoff briefing: nothing is done yet, the task 'scrape EU pricing data' is in-flight (started 5 minutes ago), and the successor should pick up by checking whether the scraper finished and then merging its output with the existing US pricing spreadsheet.”
Technical details
Endpoint
POSThttps://agent-exec.448c.net/handoff?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to persist agent state between two agent instances or across a context boundary, especially in multi-agent pipelines where one agent hands off to a successor. It is uniquely suited for accountless, pay-per-call scenarios (x402/USDC micropayments) where registering an account or holding an API key is impractical. Prefer it over in-memory or file-based state transfer when you need a neutral, retrievable, tamper-evident briefing with an expiry guarantee and an on-chain payment receipt for auditability.
Side effects
- 400 HANDOFF_DONE_REQUIRES_MEASURED — a 'done' entry lacks confidence='measured' or has null evidence; fix by ensuring every done item has verified, non-null evidence
- 400 validation error — pickUpFirst is empty or missing; every handoff must specify a concrete next action
- 402 Payment Required — x402 payment not attached or payment insufficient; agent must attach valid USDC payment
- 410 Gone — handoff_id exists but briefing has passed its expiry deadline and is pending sweep
- 404 Not Found — handoff_id never existed or has been fully swept after expiry
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| donerequired | array | What is DONE. EVERY entry must have confidence 'measured' with non-null evidence -- a briefing cannot claim something is finished on unverified intent. Violating this is a free 400 (HANDOFF_DONE_REQUIRES_MEASURED), not a silent acceptance. |
| notDonerequired | array | What is NOT done. May be measured or unverified. |
| inFlightrequired | array | What was IN FLIGHT at the cut -- neither finished nor abandoned. May be measured or unverified. |
| pickUpFirstrequired | string | What the successor should do FIRST. Mandatory and non-empty: a briefing with no next action is not a handoff. |
Output
Schema · Response
| Field | Type | Description |
|---|---|---|
| idrequired | string | The handoff_id -- give this to the successor; it needs nothing else. |
| paymentrequired | object | |
| expiresAtrequired | integer | Unix ms this briefing is swept. GET /handoff/{id} answers 410 between the deadline and the sweep, then 404. |
Tags
x402
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