calesthio FLUX Best Practices
Use this skill when generating prompts for any BFL FLUX model to ensure optimal image quality and accurate prompt interpretation.
Extended reference:
AGENTS.mdin this directory is the long-form upstream FLUX guide (vendored from Black Forest Labs). It is supplementary reference material scoped to this skill only —SKILL.mdis the loadable entry point and the authority. It does not override or extend the repository-rootAGENTS.md/AGENT_GUIDE.md.
When to Use
- Creating prompts for FLUX.2 or FLUX.1 models
- Text-to-image (T2I) generation
- Image-to-image (I2I) editing with FLUX.2 models
- Structured scene generation with JSON
- Typography and text rendering
- Multi-reference style transfer
- Color-accurate brand generations
Quick Reference
Prompt Structure Formula
[Subject] + [Action/Pose] + [Style/Medium] + [Context/Setting] + [Lighting] + [Camera/Technical]
Model Selection
| Use Case | Recommended Model | Notes |
|---|---|---|
| Fastest generation | FLUX.2 [klein] | 4B or 9B, sub-second |
| Highest quality | FLUX.2 [max] | Best detail, grounding search |
| Production balanced | FLUX.2 [pro] | Quality + speed |
| Typography/text | FLUX.2 [flex] | Best text rendering |
| Local/development | FLUX.2 [dev] | Open weights |
| Image editing | FLUX.2 [pro/max] | Pass image URL directly to input_image |
| Inpainting | FLUX.1 Fill | Object removal/completion |
| Context editing | FLUX.1 Kontext | Older model, prefer FLUX.2 |
Critical Rules
- NO negative prompts - FLUX does not support negative prompts; describe what you want
- Be specific - Vague prompts produce mediocre results
- Use natural language - Prose/narrative style works best
- Specify lighting - Lighting has the biggest impact on quality
- Quote text - Use "quoted text" for typography rendering
- Hex colors - Use #RRGGBB format with color description
Related
For API integration (endpoints, polling, webhooks), see the bfl-api skill.
Rules Reference
Read individual rule files for detailed guidance:
- rules/core-principles.md - Universal FLUX prompting principles
- rules/flux2-models.md - FLUX.2 family: klein, max, pro, flex, dev
- rules/flux1-models.md - FLUX.1 family: older generation of FLUX.2 models - pro, Kontext, Fill
- rules/t2i-prompting.md - Text-to-image prompting patterns
- rules/i2i-prompting.md - Image-to-image editing with FLUX.2
- rules/json-structured-prompting.md - Complex scene composition
- rules/hex-color-prompting.md - Precise color specification
- rules/typography-text.md - Text rendering and typography
- rules/multi-reference-editing.md - Multi-image references
- rules/negative-prompt-alternatives.md - Positive alternatives
- rules/model-selection-guide.md - Choosing the right model
Example Prompt
A weathered fisherman in his 70s with deep wrinkles and a salt-and-pepper beard,
wearing a navy cable-knit sweater, standing at the helm of his wooden boat.
Golden hour sunlight from the left creates dramatic rim lighting on his profile.
Shot on Hasselblad with 85mm lens at f/2.8, shallow depth of field with harbor
lights creating soft bokeh in the background. Kodak Portra 400 color science.