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WithZero Scheduler - Create Task
WithZero Scheduler - Create Task is a paid API for AI agents from agents.withzero.xyz, paid per call via MPP, $1/call, status healthy (last checked 2026-09-15, last successful call 2026-09-04).
Creates a new recurring (cron-scheduled) or on-demand AI agent task with escrow-based billing, optional LLM access, tool lists, dependencies, and environment variables.
Price / call$1session · ~$1 to open
Success100%
StatusHealthy
How this service works
Create a recurring or on-demand task. Direct endpoint: max_amount_usdc_micros is refundable escrow and X-Pay-Amount-Micros must match it. ZeroClick endpoint: it is a seller-local lifetime execution cap; marketplace access/usage is authoritative and no seller escrow is created. Optional: schedule, max_sibling_calls, llm, tool_list, dependencies, env, notify_email, end_at. See GET /api/v1 and /llms.txt for rail-specific setup.
Output
Returns a JSON object containing the new task's UUID, initial status, next scheduled run timestamp, billing rail (direct or zeroclick), payment channel ID and opening transaction hash, maximum escrow amount, current available balance, estimated execution ceiling (all in USDC micros), the cron expression, and timezone.
Example use cases
Daily market research automation
“Create a scheduled task that runs every weekday morning at 7am UTC, uses the 'research' LLM profile, pulls the latest news about my industry, and emails a digest to team@mycompany.com — give it a max runtime of 300 seconds and a $10 USDC escrow cap.”
On-demand data pipeline trigger
“Register an on-demand agent task with no schedule that I can trigger manually — it should run a Python script, have a max runtime of 60 seconds, a $2 USDC spending cap, and have my database URL injected as DATABASE_URL in the environment.”
Recurring social media publisher
“Set up a task that runs every Monday at 9am UTC using the 'quick' LLM profile to generate and publish a weekly update post — max runtime 90 seconds, $3 USDC cap, notify me at founder@startup.io when each run completes.”
Technical details
Endpoint
POSThttps://agents.withzero.xyz/api/v1/scheduler/tasksWhen to prefer
Use this endpoint when you need to create a new autonomous agent task — either scheduled on a cron or triggered on-demand — with a defined spending cap and optional LLM access. Prefer the direct rail when you want refundable USDC escrow linked to a payment channel; prefer ZeroClick when operating through a marketplace where access is marketplace-authoritative. Use this over generic cloud scheduler services when your task needs built-in LLM broker access, pay-per-use billing, and no vendor API key management.
Side effects
- 400 PRICE_RESOLVER_FAILED — X-Pay-Amount-Micros header is missing, non-integer, or does not exactly match max_amount_usdc_micros in the request body
- 400 validation error — required fields (runtime, source, entrypoint, max_runtime_sec, max_sibling_calls, max_amount_usdc_micros) are missing or malformed
- 402 Payment Required — payment challenge not satisfied by the client before task is created
- 409 conflict — same Idempotency-Key reused with a different body (different semantics from safe retry)
- 429 rate limit — too many task creation requests in a short window
- 500 internal error — sandbox provisioning or payment channel open failure
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| env | object | BYO env vars injected into the sandbox. Never returned in any GET response. |
| llm | object | Enables the built-in LLM for your source (call generate_text(...) — pre-imported, auto-authenticated). Omit to disable LLM calls. Pick a profile (quick|standard|bulk|research|long); GET /api/v1/rates → llm_profiles lists each profile's models, default_model, and caps. FUNDING: the chosen profile's max_cost_usdc_micros_per_run is reserved into estimated_ceiling_micros every run (quick $0.05, standard $0.15, bulk $0.15, research $1.00, long $2.00), so raise max_amount_usdc_micros to match — or lower the reserve with max_cost_usdc_micros_per_run. |
| end_at | string | Optional ISO-8601 auto-stop time. The dispatch loop flips status to `completed` once now() >= end_at. |
| sourcerequired | string | Verbatim code for the run, written to /workspace/<entrypoint>. It can reach the public internet, and four helpers are available as GLOBALS — no import, no keys, no setup: generate_text(...) for the built-in LLM (needs an `llm` profile on the task), call(sibling, path, body?, method?, max_price_micros?) to invoke another Zero capability through the per-run proxy, store_artifact(name, data, content_type?) for durable cdn hosting (needs `artifacts.enabled`), and request_continuation(delay_sec?) to schedule an immediate follow-up run when the work is larger than one run cap (chunk → persist progress externally → request_continuation() → exit 0; granted only on a clean exit, capped back-to-back). Call them directly — e.g. python `r = generate_text('hi')`, node `const r = await call('cdn','/x')`. (The explicit `from withzero_sdk import generate_text, call, store_artifact` / `import { generateText, call, storeArtifact } from './withzero-sdk.js'` also works but is optional.) `generate_text` accepts optional OpenRouter reasoning config. CALL() CONTRACT: every helper returns `{ status, body }` where `status` is the upstream HTTP status (int) and `body` is the parsed JSON response (or null). In node these are ASYNC — `await call(...)` / `await generate_text(...)`; in python they are SYNCHRONOUS — `r = call(...)` (no await). call() TARGETS, two kinds: (a) a FIRST-PARTY sibling by NAME (urlshortener/cdn/forms/screenshot/inbox) — billed a flat per-call fee, no max_price_micros needed. (b) ANY PAID marketplace capability by its capabilityId. PAID MARKETPLACE FLOW (discover-then-cap): the sandbox has public internet egress, so to call a paid third-party capability you FIRST discover its `capabilityId`, price, accepted payment protocol (x402 or MPP), and request path/body by querying Zero yourself at https://api.zero.xyz (capability search/get; the capability's OWN OpenAPI describes its request path + body). THEN call it as `call(capabilityId, path, body?, method?, max_price_micros)` — pass the capabilityId as the FIRST arg and max_price_micros (the most USDC micros you accept for this one call). The scheduler resolves the capabilityId server-side, pays via x402 (from a Base float) or MPP (from Tempo escrow) out of the escrow wallet, enforces your cap before signing, and refunds the difference — you never handle keys or sign anything. EXAMPLE (paid, python): `r = call("cap_abc123", "/v1/enrich", {"domain": "acme.com"}, max_price_micros=50000)` — pays at most 0.05 USDC for one call to capability cap_abc123. ERROR CODES a call() may surface in the proxy response: PRICE_CAP_EXCEEDED (the paid challenge exceeded your max_price_micros — payment aborted before signing, nothing spent), PRICE_UNKNOWN (missing/invalid max_price_micros or capabilityId for a paid target), CAPABILITY_PROTOCOL_UNSUPPORTED (the capability offers neither x402 nor MPP), SIBLING_NOT_ALLOWED (target not in the task `tool_list`), CALL_CAP_EXCEEDED (per-run max_sibling_calls hit), SIBLING_PAYMENT_FAILED (resolution/settlement failed; reservation released). ALLOWLIST: a target (sibling name or capabilityId) is callable only when it is in the task `tool_list`, OR when `tool_list` is left open with `max_sibling_calls` > 0 (then `max_sibling_spend_micros` is REQUIRED and bounds total per-run paid spend). The full catalog + worked examples are at GET /api/v1 (the `sandbox` section). |
| runtimerequired | string | Sandbox runtime; 'python' or 'node'. |
| schedule | — | Either a raw cron expression or a convenience shape; the convenience shape compiles to a 5-field cron string server-side. |
| artifacts | object | Optional durable artifact storage for sandbox code via the cdn capability. Omit to disable. Free in v1; bounded by per-run caps. |
| tool_list | array | Allowlist of capability identifiers the run may proxy through — first-party sibling names (urlshortener/cdn/forms/screenshot/inbox) AND/OR marketplace capabilityIds. THREE states: OMIT the field → OPEN proxy when `max_sibling_calls` > 0 (reach ANY capability; `max_sibling_spend_micros` is then REQUIRED to bound spend) — with `max_sibling_calls` 0/omitted it is stored as DENY-ALL instead; send `[]` → DENY-ALL (every capability is blocked; the safe restriction default); send `[items]` → SCOPED to exactly those identifiers. An explicit `[]` is NOT open — only an omitted tool_list with `max_sibling_calls` > 0 is. Marketplace capabilityIds (and their pricing/protocol) are discovered via Zero's capability search at https://api.zero.xyz; first-party sibling names + their per-call openapi are listed at GET /api/v1/_siblings. |
| entrypointrequired | string | File name for `source` (e.g. 'main.py' or 'index.js'). |
| dependencies | object | Optional extra packages installed in the sandbox prelude; max 20 per runtime. **Always pin versions** — sandboxes install fresh on every run, so an unpinned package silently upgrades when a new major ships. Node: "name@version" or "@scope/name@version" (e.g. ["mppx@0.7.0", "viem@2.21.0"]). Python: "name==version" (e.g. ["requests==2.31.0"]). |
| notify_email | string | Optional address for best-effort run-completion emails. When set, each scheduled (cron) or async `/trigger` run sends one email on finalize with its status, duration, cost, and the tail of stdout. Synchronous runs (`/runs`, `/webhook`) do not email — the result is returned inline. Delivery never blocks or fails a run. |
| max_runtime_secrequired | integer | Hard cap on per-run wall-clock seconds; max 900. |
| max_sibling_callsrequired | integer | Hard cap on sibling proxy calls per run; max 1000. Defaults to 0 — no sibling calls; set it > 0 to let `source` use call(...). |
| max_amount_usdc_microsrequired | string | Channel deposit ceiling in USDC micros (positive integer as string, or number up to 2^53-1). Bounds total lifetime spend. Size it >= estimated_ceiling_micros * (runs you want before a top-up); if it is below one ceiling the task pauses before its first run. LLM-enabled tasks reserve the profile cost cap per run — see the `llm` field. |
| max_sibling_spend_micros | string | Optional per-run sibling-spend ceiling in USDC micros (positive integer as string, or number up to 2^53-1). REQUIRED when `tool_list` is omitted AND `max_sibling_calls` > 0 (open proxy) so spend stays bounded; optional otherwise. Replaces the legacy max_sibling_calls × per-call-fee reservation in the run ceiling. |
Output
Schema · Response
| Field | Type | Description |
|---|---|---|
| idrequired | string | |
| cronrequired | — | |
| statusrequired | string | |
| timezonerequired | string | |
| channel_idrequired | — | |
| next_run_atrequired | — | |
| billing_railrequired | string | |
| channel_open_txrequired | — | |
| max_amount_microsrequired | string | |
| balance_available_microsrequired | string | |
| estimated_ceiling_microsrequired | string |
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