# WithZero Scheduler — Synchronous Task Run

> WithZero Scheduler — Synchronous Task Run is a paid API for AI agents from agents.withzero.xyz, paid per call via MPP, price unknown, status unknown (last checked 2026-09-12).

Immediately claims and executes a scheduled task inline, blocking until the run completes, then returns the finalized run record.

## Facts

- Endpoint: POST https://agents.withzero.xyz/api/v1/scheduler/tasks/{id}/runs
- Price: price unknown
- Payment: MPP
- Status: unknown
- Last checked: 2026-09-12
- Activations on Zero: 1
- Provider: agents.withzero.xyz
- Website: https://agents.withzero.xyz
- Canonical page: https://www.zero.xyz/c/agents-withzero-xyz-withzero-scheduler-synchronous-task-run-20caad38
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PeOeSghbGFzUseNjVULiM

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 agents-withzero-xyz-withzero-scheduler-synchronous-task-run-20caad38 -d '<json body>'
```

Example prompt: Run my scheduler task with ID a3f1c2d4-89ab-4def-8765-1234567890ab right now and wait for it to finish — I want to verify it works before I rely on the cron schedule.

## When to prefer this

Use this endpoint when you need to run a task immediately and must wait for the result before proceeding — ideal for testing a newly created cron task, debugging a task interactively, or triggering an on-demand execution where the outcome is needed synchronously. Prefer the async trigger endpoint if you don't need to block and just want to fire-and-forget. This endpoint does NOT advance next_run_at, so it won't disrupt your scheduled cadence.

## Known failure modes

- Task ID not found or caller lacks ownership proof — returns 404 or 403
- Task is already running or locked — may return conflict error
- Sandbox execution timeout — run may finalize with a failed/timeout status
- Invalid UUID format in path parameter — returns 400
- Insufficient escrow/payment balance — returns 402

## How this service works

Run a task right now, synchronously: claims, runs the sandbox inline, and blocks until the run finalizes, then returns it. Billed like a normal cron run. Use it to trigger an on-demand run or to test a cron you just set up before trusting the schedule. Does NOT advance next_run_at. 📖 Full guide: https://scheduler.withzero.xyz/llms.txt

## Output

Returns a run record containing: run_id (UUID), task_id (UUID), status string indicating the final run outcome, trigger string indicating how the run was initiated, and claimed_at timestamp showing when the sandbox claimed the task. The response is only returned after the run fully finalizes (blocking).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {},
 "description": "Empty body. Runs the task immediately and synchronously — blocks until the run finalizes, then returns it.",
 "additionalProperties": false
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "run_id",
  "task_id",
  "status",
  "trigger",
  "claimed_at"
 ],
 "properties": {
  "run_id": {
   "type": "string",
   "format": "uuid",
   "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
  },
  "status": {
   "type": "string"
  },
  "task_id": {
   "type": "string",
   "format": "uuid",
   "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
  },
  "trigger": {
   "type": "string"
  },
  "claimed_at": {
   "type": "string"
  }
 },
 "additionalProperties": false
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agents-withzero-xyz-withzero-scheduler-synchronous-task-run-20caad38/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agents.withzero.xyz](https://www.zero.xyz/host/agents.withzero.xyz/llms.txt)