MCP Resources

image-generation-mcp exposes resources for provider information and image access.

info://providers

Provider capabilities and supported features.

MIME type: application/json

Response

{
  "providers": {
    "placeholder": {
      "available": true,
      "description": "Zero-cost solid-color PNG — instant, no API key, for testing and drafts",
      "capabilities": {
        "provider_name": "placeholder",
        "models": [
          {
            "model_id": "placeholder",
            "display_name": "Placeholder (solid-color PNG)",
            "can_generate": true,
            "can_edit": false,
            "supports_mask": false,
            "supported_aspect_ratios": ["1:1", "16:9", "9:16", "3:2", "2:3"],
            "supported_qualities": ["standard"],
            "supported_formats": ["png"],
            "supports_negative_prompt": false,
            "supports_background": true,
            "max_resolution": 640,
            "default_steps": null,
            "default_cfg": null,
            "prompt_style": null
          }
        ],
        "supports_background": true,
        "supports_negative_prompt": false,
        "discovered_at": 1710777600.0,
        "degraded": false
      }
    },
    "openai": {
      "available": true,
      "description": "OpenAI (gpt-image-1 / dall-e-3) — best for text, logos, and general-purpose generation",
      "capabilities": {
        "provider_name": "openai",
        "models": [
          {
            "model_id": "gpt-image-1",
            "display_name": "GPT Image 1",
            "can_generate": true,
            "can_edit": true,
            "supports_mask": true,
            "supported_aspect_ratios": ["1:1", "16:9", "9:16", "3:2", "2:3"],
            "supported_qualities": ["standard", "hd"],
            "supported_formats": ["png", "jpeg", "webp"],
            "supports_negative_prompt": false,
            "supports_background": true,
            "max_resolution": 1536,
            "default_steps": null,
            "default_cfg": null,
            "prompt_style": null
          }
        ],
        "supports_background": true,
        "supports_negative_prompt": false,
        "discovered_at": 1710777600.0,
        "degraded": false
      }
    }
  },
  "supported_aspect_ratios": ["1:1", "16:9", "9:16", "3:2", "2:3"],
  "supported_quality_levels": ["standard", "hd"],
  "supported_backgrounds": ["opaque", "transparent"]
}

Only registered (configured) providers appear. Degraded providers (where capability discovery failed at startup) show "degraded": true with an empty models list -- they remain available for generation.

---

info://prompt-guide

Provider-specific prompt writing guidance for LLM clients. Read this resource to learn how to write effective prompts for each provider.

MIME type: text/markdown

Content

Markdown document covering:

• General tips — aspect ratio selection, quality levels, when to use negative prompts
• OpenAI — natural-language prompts, style keywords, text rendering tips
• SD WebUI (Stable Diffusion) — CLIP tags for SD 1.5/SDXL, natural language for Flux, negative prompts, BREAK syntax, model-specific advice
• Placeholder — prompt-to-color mapping explanation

The generate_image tool description references this resource. LLM clients can read it before generating images to produce better prompts.

---

image://{id}/view

Image data with optional CDN-style transforms. This is a resource template (RFC 6570) with query parameters.

URI template: image://{image_id}/view{?format,width,height,quality}

MIME type: varies (depends on original format or requested format)

Parameters

Parameter	Type	Default	Description
format	str	(original)	Convert to png, webp, or jpeg
width	int	(original)	Target width in pixels
height	int	(original)	Target height in pixels
quality	int	90	Compression quality for lossy formats (1-100)

Transform behavior

Parameters provided	Behavior
None	Returns original bytes unchanged
format only	Format conversion (e.g. PNG to WebP)
width + height	Center-crop to exact dimensions
width only	Proportional resize (height calculated from aspect ratio)
height only	Proportional resize (width calculated from aspect ratio)
format + dimensions	Convert and resize/crop

Examples

# Original image
image://a1b2c3d4e5f6/view

# Convert to WebP
image://a1b2c3d4e5f6/view?format=webp

# Resize to 512px wide (proportional)
image://a1b2c3d4e5f6/view?width=512

# Center-crop to 256x256
image://a1b2c3d4e5f6/view?width=256&height=256

# Convert to JPEG at quality 85
image://a1b2c3d4e5f6/view?format=jpeg&quality=85

---

image://{id}/metadata

Sidecar JSON metadata with generation provenance.

MIME type: application/json

Response

{
  "id": "a1b2c3d4e5f6",
  "content_type": "image/png",
  "provider": "openai",
  "prompt": "a watercolor painting of mountains at sunset",
  "negative_prompt": null,
  "aspect_ratio": "16:9",
  "quality": "standard",
  "original_dimensions": [1536, 1024],
  "provider_metadata": {
    "model": "gpt-image-1",
    "size": "1536x1024",
    "quality": "standard",
    "api_quality": "high"
  },
  "created_at": 1710777600.0
}

---

image://list

List all registered images and pending generations.

MIME type: application/json

Response

Each item includes a status field: "completed" for registered images, "generating" or "failed" for pending background generations.

[
  {
    "image_id": "a1b2c3d4e5f6",
    "provider": "openai",
    "prompt": "a watercolor painting of mountains at sunset",
    "aspect_ratio": "16:9",
    "created_at": 1710777600.0,
    "status": "completed"
  },
  {
    "image_id": "c3d4e5f6a7b8",
    "provider": "sd_webui",
    "prompt": "a cyberpunk cityscape",
    "status": "generating",
    "progress": 0.3,
    "progress_message": "Step 9/30 (ETA 12s)"
  },
  {
    "image_id": "b2c3d4e5f6a7",
    "provider": "placeholder",
    "prompt": "test image",
    "aspect_ratio": "1:1",
    "created_at": 1710777500.0,
    "status": "completed"
  }
]

Pending generations (status "generating" or "failed") appear in the list alongside completed images. They are cleaned up automatically after a 10-minute TTL.

---

ui://image-viewer/view.html

Interactive image viewer rendered by MCP Apps-capable clients (Claude Desktop, claude.ai).

MIME type: text/html

This resource is an MCP App — a custom HTML page loaded in a sandboxed iframe. It listens for show_image tool results and displays the image with metadata. The show_image tool is wired to this resource via AppConfig(resourceUri=...).

The viewer persists rendered images in localStorage (keyed by image ID, LRU-capped at 5 entries). When a new widget instance loads, the ontoolinput handler restores cached state immediately so the image is visible before the tool result arrives. The live ontoolresult always takes precedence over the cached version.

The widget does not render download links — the sandboxed iframe cannot navigate to external URLs. When download_url is present in the show_image metadata, the LLM should present it directly to the user as a clickable link in the conversation text.

Clients without MCP Apps support ignore this resource entirely.