---

name: backend-and-api description: "Reason about Dream Textures backend API contracts, DiffusersBackend routing, generator subprocess behavior, schedulers, model/task compatibility, and custom backend diagnosis." disable-model-invocation: true metadata: disco-role: operating license: GPL 3.0

Backend and API

Use this sub-skill when a task is about Dream Textures' backend extension surface or local Diffusers backend internals rather than a user-facing prompt recipe.

Route Here

• Implement or update a custom backend, including Backend.generate(arguments, step_callback, callback) and GenerationResult callbacks.
• Inspect or reason about GenerationArguments, Task dataclasses, Prompt, Model, ControlNet, GenerationResult, SeamlessAxes, or StepPreviewMode.
• Diagnose DiffusersBackend model/task validation, scheduler enum errors, device selection, model cache invalidation, checkpoint conversion/loading, SDXL refiner behavior, ControlNet routing, or optimization flags.
• Understand the Generator actor/Future callback lifecycle without running Blender UI, model downloads, or original repository tests.
• Handle source-level symptoms such as missing bpy outside Blender, stale community backend signatures, cancellation that never calls back, or optional backend dependency import failures.

Start With

• API Reference for verified public dataclass, enum, and Backend method signatures.
• Diffusers Backend for task routing, model loading, scheduler values, device order, optimizations, and compatibility checks.
• Custom Backends when writing or porting a backend.
• Troubleshooting for symptom-oriented backend/API diagnosis.
• scripts/inspect_public_api.py for safe signature/enum inspection in a minimal Python environment with NumPy and either an installed Dream Textures package or a supplied add-on source directory.

Boundaries

• End-user prompt, inpaint/outpaint, ControlNet-from-image, history, seamless texture, and upscaling recipes belong in the sibling generation-workflows sub-skill.
• Installation, dependency variants, model acquisition, Hugging Face tokens, DreamStudio keys, and checkpoint import UI guidance belong in setup-and-models.
• Texture projection, scene nodes, annotation maps, render passes, compositor sockets, and Cycles integration belong in scene-integration.
• Do not treat full Stable Diffusion inference, Blender UI execution, or original repository tests as required checks for this sub-skill; use source-backed reasoning and safe helper inspection.

Safe Inspection Pattern

python scripts/inspect_public_api.py --help
python scripts/inspect_public_api.py --addon-dir /path/to/dream_textures --json

The helper sets backend/actor inspection stubs, avoids Blender UI imports, and does not download models. If the user's add-on directory is already installed/importable as dream_textures, --addon-dir can be omitted. A direct source directory with another basename is inspected via sys.path insertion using that basename only; no symlink, copy, or source mutation is performed.