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CanonSheet Character Prompt Builder
x402
CanonSheet Character Prompt Builder is a paid API for AI agents from canonsheet.kaneky.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-11).
Generates a consistent, labeled prompt set for a single human character—including canonical image prompt, negative prompts, video prompt, and optional contact-sheet walk—for use with any image or video generation model.
Price / call$0.02
Success—
StatusUnknown
How this service works
Build a consistent prompt set for one human character: a canonical image prompt with every appearance fact labelled, negative prompts that stop traits like glasses or a cane from vanishing, a video prompt, and optionally a contact sheet that holds everything fixed and walks one axis. Works with any image or video model. Text keeps wardrobe and framing stable; for the same FACE across images, generate the canonical frame once and pass it back as a reference image (has_reference). Paid per call over x402: the first attempt answers HTTP 402 with the price. Invalid arguments are refused before any payment.
Output
Returns a structured prompt set containing: a canonical image prompt with every appearance detail explicitly labeled, one or more negative prompts preventing trait drift (e.g. glasses, mobility aids, tattoos), a video prompt with camera and motion settings, and optionally a series of contact-sheet prompts that hold all variables fixed while stepping through one chosen axis (such as style, lighting, or shot size).
Example use cases
Stable protagonist across illustration series
“Create a full prompt set for Marcus, a tall Black man in his 40s with salt-and-pepper locs, a scar on his left cheek, and a long charcoal coat — medium shot, three-quarter turn angle, 85mm lens, cinematic style, overcast lighting in a rainy city street. Include negative prompts so his scar and coat never vanish, and also give me a video prompt with a turn-to motion and a gentle breeze ambient.”
Contact sheet walk for costume variations
“I need a contact sheet for Yuki — petite Japanese woman, early 20s, violet eyes, undercut hair dyed silver, usually holding a sketchbook — lock everything to a close shot, eye-level, 50mm lens, soft-key lighting, illustration style, and walk the style axis so I can see how she looks across photo, cinematic, painterly, and anime renders.”
Video ad character with reference image
“Build me a video prompt for a recurring brand character named Leo: medium-build Latino man, late 30s, warm olive skin, thick dark eyebrows, wearing a white chef's apron — three-quarter shot, low angle, rim lighting, practical ambient, push-in camera, and a speak motion. I already have a canonical reference image for his face, so set has_reference to true.”
Technical details
Endpoint
POSThttps://canonsheet.kaneky.dev/api/build_character_prompts?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to lock a character's appearance across multiple AI-generated images or video clips and prevent trait drift — especially when the character has distinctive features like glasses, facial hair, a mobility aid, or tattoos that tend to disappear between generations. It is purpose-built for prompt engineering workflows rather than direct image generation, so prefer it when your downstream tool is any image or video model and you want a reusable, labeled prompt corpus rather than a one-off image. Prefer it over generic prompt templates when you need structured negative prompts and optional contact-sheet enumeration.
Side effects
- Invalid enum value for choices/shot, angle, lens, lighting, style, or video fields — request refused before payment with a 400-level error
- Missing or malformed required fields — rejected prior to charging
- HTTP 402 returned on first call with pricing information (expected behavior, not a true failure — retry with payment)
- Payment not completed or x402 flow not followed — no prompts returned
- Exceeding maxItems 6 on custom_traits — request refused
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| name | string | |
| video | object | |
| traits | object | |
| choices | object | |
| walk_axis | string | |
| appearance | object | |
| custom_traits | array | |
| has_reference | boolean |
Tags
x402
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