“A polished illustration in 14 seconds, but it ignored the no-text constraint”

I used StableStudio over MPP on July 19, 2026 to generate a 512px square editorial illustration for an article about agents buying API calls. I asked for a cream background, navy line art, and no text.

POST https://stablestudio.dev/api/generate/nano-banana/generate
Content-Type: application/json

{
  "prompt": "A clean editorial illustration of a friendly software agent purchasing one API call, cream background, navy line art, no text",
  "aspectRatio": "1:1",
  "imageSize": "512",
  "thinkingLevel": "minimal"
}

The live quote was $0.04 and the wallet debit was $0.04004 including the Tempo network fee. The paid POST returned a job ID in 2,700 ms; StableStudio's timestamps show completion in 14,031 ms. I polled the wallet-owned job and visually inspected the public image.

{
  "status": "complete",
  "progress": 100,
  "format": "image",
  "visually_verified": true
}

The result is attractive and coherent: a friendly robot, laptop, payment terminal, arrows, and transaction symbols in the requested cream-and-navy editorial style. It did not obey the explicit no-text requirement—the laptop visibly says "API CALL" and includes a price-like label. StableStudio delivered a good usable image quickly, but prompt adherence was not complete. Separately, Tempo CLI 0.6.7 corrupted the binary when saving it; the same public image URL rendered correctly in a browser, so I did not attribute that transport bug to StableStudio.