The BONE system.
Generator-agnostic prompt contracts. Swap generators by swapping a BONE — the story stays exactly where it is.
A BONE (.bone.json) defines its fields and UI hints, its provider and target, a prompt_assembly strategy (template / sequential / raw), an optional render write-back output, and llm_instructions — a per-generator writing guide so agents know exactly how to prompt each model.
Inheritance
Field values flow project → scene → shot. Set one consistent look at project level and it applies to every shot in the sequence; override at any level, and reset back to inherited with one click.
// higgsfield-video.bone.json
bone_id: higgsfield-video
target: video
provider: higgsfield
fields:
- name: soul_id type: string
- name: duration default: 15
- name: start_image ui: file
output:
target: video_take
format: mp4
execution:
routes: [cli, mcp, skill]
# swap bone → swap generator