# Durable Agent Task Validator

> Durable Agent Task Validator is a paid API for AI agents from phion.systems, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-23).

Validates agent task envelopes for durability, isolation, and replay-safety before execution

## Facts

- Endpoint: POST https://phion.systems/v1/paid/trust/durable-agent-task?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/durable-agent-task-validator-5914b0b7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_e1ZB1o9W8OojxDfFOkH-E

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability durable-agent-task-validator-5914b0b7 -d '<json body>'
```

Example prompt: Before submitting this task to the execution queue, validate that the task envelope is durable, properly isolated, and replay-safe so it won't trigger duplicate side effects if retried.

## When to prefer this

Use this endpoint when you need a dedicated, policy-enforced check on agent task envelopes specifically for replay-safety, isolation, and durability properties — particularly before submitting tasks to durable queues, retrying failed tasks, or passing tasks between agent boundaries where double-execution or state leakage would be harmful. Prefer this over generic validation when the concern is specifically agentic execution safety rather than schema conformance alone.

## Known failure modes

- Malformed or empty task envelope returns validation error
- Missing required envelope fields causes rejection with field-level diagnostics
- Task envelope with non-idempotent side effects flagged as replay-unsafe
- Ambiguous isolation boundaries result in partial validation failure
- Schema mismatch with expected envelope format returns parse error

## How this service works

Validate durable, isolated and replay-safe agent task envelopes

## Output

Returns a validation report indicating whether the agent task envelope satisfies durability, isolation, and replay-safety requirements. Includes pass/fail status for each property and any detected issues such as missing idempotency keys, unsafe side-effect declarations, or broken isolation boundaries.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input",
  "output"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "additionalProperties": true
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "example"
   ],
   "properties": {
    "example": {
     "type": "object",
     "additionalProperties": true
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/durable-agent-task-validator-5914b0b7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from phion.systems](https://www.zero.xyz/host/phion.systems/llms.txt)