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The Stealth Agent is StealthGPT’s premium long-form content API. It replaces the legacy business: true flag on /api/stealthify with a complete generation pipeline that researches the topic, drafts the content, optionally fact-checks it, humanizes the prose, and (optionally) inserts images. If you used to enable business: true for higher-quality output, this is your migration target.

Synchronous endpoint

POST /api/stealthify/agent — wait for the final markdown in one long-running HTTP request.

Async runs endpoint

POST /api/stealthify/agent/runs — create a run, poll status, and optionally receive a webhook callback.

Why Stealth Agent

A single-pass humanizer (the /api/stealthify endpoint) is excellent at rewriting text you already have. For long-form generation where the model has to plan, research, cite, and write from scratch, a single pass is not enough. The Stealth Agent runs each step as a dedicated stage with its own model, prompt, and validation:

Researched, not invented

Web research grounds the draft in real sources before the writing model sees the prompt, reducing hallucinations.

Optional fact-checking

enableFactCheck: true runs an additional pass that verifies claims and rewrites unsupported ones before humanization.

Humanized last

Humanization runs after drafting and fact-checking, so the final text reads naturally and stays low-detection.

Format-aware output

Each preset returns markdown shaped for its medium — academic structure with citations, SEO sections with headings, or platform-tuned social posts.

Presets

The endpoint accepts a discriminated union on preset. You pick the preset that matches your output, and the agent picks the right pipeline.
Use for: essays, literature reviews, study-guide style explainers, research-paper drafts.Pipeline: web research → academic draft → optional fact-check → humanize → academic post-processing (citations + optional images).Returns markdown with citations formatted in your chosen style (APA by default).

What you get back

Every successful run returns final markdown plus billing metadata. The synchronous endpoint returns it directly as 200 OK; the async endpoint returns it from polling or webhook callback once the run is completed.
FieldWhat it is
resultFinal humanized content as markdown. The exact same content stored against documentId.
runIdServer-side identifier of the run. Useful for support tickets and future replay endpoints.
documentIdIdentifier of the persisted document for this run.
presetEchoes your input preset.
outputWordsWord count of result, used for billing.
creditsSpentceil(outputWords × 10) Stealth API words charged for this run.
remainingCreditsPrepaid balance after the charge.
billingMode"prepaid" or "payg".
meteredChargedCreditsWords billed to metered usage (0 when fully prepaid).
See the synchronous endpoint reference or async runs reference for complete schemas and error codes.

Billing model

Stealth Agent uses the same Stealth API balance and pay-as-you-go rules as /api/stealthify, but charges by output:
  • creditsSpent = ceil(outputWords × 10) — input length does not change the price.
  • Billing falls back from prepaid balance to pay-as-you-go automatically when terms are accepted and a payment method is on file.
  • Cancelled requests (HTTP 499) are not charged.
See Pricing for full rate cards and tiers.

How long does a run take

Stealth Agent runs are multi-step and can take several minutes. For direct synchronous calls, the server allows up to 600 seconds per request and your client must use a 10-minute timeout. For production integrations, use async runs so your create request returns immediately and the final result is delivered through polling or webhook. The usage guide walks through timeout configuration, balance preflight checks, error recovery, and idempotency considerations end-to-end.

Next steps

Usage guide

End-to-end walkthrough: pick a preset, configure the client, handle errors, and ship to production.

Use cases

Concrete prompts and recommended preset/option combinations for common workflows.

Async runs

Create runs, poll status, receive callbacks, and use idempotency keys.