Forge Painter — MCP Server

An MCP server for SD WebUI Forge (Neo Branch) that exposes image generation tools to Claude Desktop and other MCP-compatible clients.

Tools

Tool	Description
txt2img	Generate an image from a text prompt
img2img	Generate an image from a prompt + input image
inpaint	Inpaint a masked region of an image
upscale_image	Upscale an image
get_models / set_model / get_current_model / refresh_models	Manage checkpoints
get_loras / get_samplers / get_embeddings / get_upscalers / get_vaes	List available assets
get_progress / interrupt_generation	Monitor and control active jobs

Compatibility

This server targets SD WebUI Forge Neo and is developed and tested against it. That said, Forge Neo's API is a superset of the standard AUTOMATIC1111 API, so sd-webui-automatic1111 (legacy A1111) may work if you point the server URL at your A1111 instance.

Untested. No compatibility testing has been done against legacy A1111. Core tools (txt2img, img2img, inpaint, get_models, get_samplers, etc.) map to standard /sdapi/v1/ endpoints and are likely to work. Tools that rely on forge-specific extensions may not behave correctly or may return errors. Use at your own risk and open an issue if you encounter problems.

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Installation

Option A — Download from Releases (recommended)

Prerequisites:

• SD WebUI Forge Neo running locally (default: http://127.0.0.1:7860)
• uv installed and on your PATH

Download the latest forge-painter.mcpb from the Releases page, then drag it into Claude Desktop (or double-click it). Claude Desktop will prompt for your Forge URL and optional credentials, then handle the rest automatically — no Python installation required.

Prompt	Default	Description
Forge URL	http://127.0.0.1:7860	URL of your Forge Neo (or A1111) instance
API Username	(blank)	Only needed if Forge was launched with --api-auth
API Password	(blank)	Only needed if Forge was launched with --api-auth
Output Directory	Documents/forge-painter	Folder where generated images will be saved

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Option B — Manual setup (development)

Prerequisites:

• Python 3.10+
• SD WebUI Forge Neo running locally (default: http://127.0.0.1:7860)

python -m venv .venv
.venv\Scripts\activate
pip install -r requirements.txt

Copy .env.example to .env and edit as needed:

copy .env.example .env

Variable	Default	Description
FORGE_URL	http://127.0.0.1:7860	Forge Neo (or A1111) instance URL
FORGE_API_USER	(blank)	Username if Forge was launched with --api-auth
FORGE_API_PASSWORD	(blank)	Password if Forge was launched with --api-auth
OUTPUT_DIR	outputs	Directory where generated images are saved
TIMEOUT_GENERATION	300	Seconds to wait for txt2img/img2img/inpaint
TIMEOUT_MODEL_SWITCH	120	Seconds to wait for a checkpoint switch

Then register the server in %APPDATA%\Claude\claude_desktop_config.json:

{
  "mcpServers": {
    "forge-painter": {
      "command": "C:\\path\\to\\forge-mcp\\.venv\\Scripts\\python.exe",
      "args": ["C:\\path\\to\\forge-mcp\\server.py"],
      "cwd": "C:\\path\\to\\forge-mcp"
    }
  }
}

Restart Claude Desktop. Forge Painter will appear in the MCP tools panel.

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Building the .mcpb yourself

One-time prerequisites:

pip install uv
npm install -g @anthropic-ai/mcpb

Build and sign:

mcpb validate manifest.json
mcpb pack . forge-painter.mcpb
$env:PATH += ";C:\Program Files\Git\usr\bin"  # provides openssl
mcpb sign forge-painter.mcpb --self-signed    # claude might not open the .mcpb when signed, do at your own peril

To publish a new release: bump version in manifest.json and pyproject.toml, rerun the build commands above, and attach the updated .mcpb as an asset to a new GitHub Release.

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Troubleshooting

• If the Forge URL is unreachable, tools return errors but the server itself still loads.
• For the .mcpb option, uv must be on your PATH when Claude Desktop launches the server.