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MCP Prompts

image-generation-mcp provides two prompts that give LLM clients guidance on provider selection and prompt formatting.

select_provider

Guidelines for selecting the best image generation provider based on the user's request.

When to use

MCP clients (like Claude) can load this prompt to understand provider strengths before calling generate_image. It helps the client make informed decisions about which provider to use.

Content summary

The prompt covers:

  • Provider strengths -- what each provider (OpenAI, SD WebUI, Placeholder) is best at
  • Selection rules -- ordered decision logic:
    1. Text/logos/typography -> use OpenAI
    2. Photorealism/portraits/product shots -> prefer SD WebUI (fall back to OpenAI)
    3. Art/illustration/anime -> prefer SD WebUI (fall back to OpenAI)
    4. Quick test/placeholder -> use placeholder
    5. General requests -> default to OpenAI
  • Usage guidance -- how to call generate_image with provider="auto" or a specific provider name

sd_prompt_guide

Guide for writing effective Stable Diffusion prompts using the CLIP-based tag format.

When to use

MCP clients should load this prompt when generating images with the SD WebUI provider. Stable Diffusion models respond better to comma-separated tags than natural language descriptions.

Content summary

The prompt covers:

  • Tag format -- comma-separated descriptive tags ordered by importance: subject, medium, style, lighting, camera, quality tags
  • Example prompts -- portrait, landscape, and product shot examples
  • Quality tags -- masterpiece, best quality, highly detailed, sharp focus, 8k, ultra high res
  • Negative prompts -- general-purpose negative prompt for avoiding common artifacts, plus photorealism and anime-specific additions
  • CLIP token limits -- SD 1.5: 77 tokens per chunk, SDXL: 77 tokens per chunk with two encoders
  • BREAK syntax -- how to separate concepts into different CLIP chunks
  • Aspect ratios -- supported ratios: 1:1, 16:9, 9:16, 3:2, 2:3

Example prompt format

1girl, long hair, blue eyes, school uniform, standing, cherry blossoms,
soft lighting, detailed face, masterpiece, best quality

See the Prompt Writing Guide for more detailed examples and tips.