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Task Checkpoint Evidence
x402
Task Checkpoint Evidence is a paid API for AI agents from phion.systems, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-20).
Binds task state, sequence number, and checkpoint hash into a signed cryptographic evidence record for AI agent task integrity
Price / call$0.003
Success—
StatusUnknown
How this service works
Bind task state, sequence and checkpoint hash in signed evidence
Output
A signed evidence record cryptographically binding the task state, sequence number, and checkpoint hash. The receipt serves as a tamper-evident attestation that can be used for audit trails, dispute resolution, or integrity verification of an AI agent's task progression.
Example use cases
Audit trail for multi-step agent pipeline
“My agent just completed the data-validation phase of a 5-step pipeline — can you create signed checkpoint evidence binding task state 'validation_complete', sequence 2, and the checkpoint hash so I have a cryptographic record before moving to the next step?”
Commerce journey integrity checkpoint
“Before my agent submits the final payment, I need a signed evidence record locking in task state 'pre_payment', sequence number 4, and the hash of the current task context so we have a tamper-proof checkpoint.”
Dispute-resolution evidence for agent task
“I need verifiable proof that my agent task reached 'delivery_confirmed' state at sequence step 6 — can you bind the task state and checkpoint hash into a signed evidence record I can use if there's a dispute?”
Technical details
Endpoint
POSThttps://phion.systems/v1/paid/trust/task-checkpoint-evidence?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a cryptographically signed, tamper-evident record binding a specific task state and sequence to a checkpoint hash — particularly for multi-step agentic workflows where you need audit trails, dispute-resolution evidence, or integrity guarantees at discrete task phases. Prefer this over generic logging when non-repudiability and signed provenance are required.
Side effects
- Invalid or missing task state returns 400 error
- Malformed checkpoint hash causes binding failure
- Sequence number out of expected order may be rejected
- Payment failure via x402 prevents evidence generation
- Signature generation failure if signing infrastructure is unavailable
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| outputrequired | object |
Output
Schema · Response
{
"type": "json"
}Tags
x402
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