rawtherapee-mcp-server 1.0.1

MCP server for AI-assisted RAW photo development via RawTherapee

RawTherapee MCP Server

Cross-platform Model Context Protocol (MCP) server for AI-assisted RAW photo development via RawTherapee CLI. Provides 37 tools for profile generation, image processing, visual previews, batch operations, device presets, and luminance-based local adjustments.

What makes it unique: The LLM can see the photos it's editing. Preview tools return inline Base64 images via MCP's ImageContent protocol, creating a visual feedback loop where the AI analyzes the image, adjusts settings, previews the result, and iterates — just like a human editor.

MCP Client Compatibility

Not all MCP clients handle inline images the same way. The visual feedback loop requires a client that renders ImageContent from tool responses and a backing LLM with vision capabilities.

Client	MCP Support	Image Display	Visual Workflow	Status
Claude Desktop	Full	Yes	Full	Tested
Claude Code	Full	No (terminal)	Partial	Tested — images not rendered in terminal, but processing and text analysis work fully
Cursor	Full	Should work	Should work	Untested — MCP docs indicate ImageContent support
Windsurf	Full	Should work	Should work	Untested
Cline	Partial	Unknown	Unknown	Untested — community reports suggest ImageContent may not render (#1865)
Zed	Full	Unknown	Unknown	Untested

Minimum requirements for the full visual workflow:

• MCP client renders ImageContent (type: "image", data: base64, mimeType: "image/jpeg") from tool responses
• Backing LLM supports vision/image analysis (e.g. Claude with vision)
• Tool response size accommodates ~150KB previews (most clients: 1MB limit)

Text-only clients: All 37 tools work without inline images. Preview tools return file paths instead. The LLM can still read EXIF metadata, histogram statistics, generate profiles, batch process, and use luminance presets — the visual feedback loop is the only feature that requires image support.

Prerequisites

• Python 3.11+
• RawTherapee 5.9+ with CLI component installed
• An MCP-compatible client (see table above)

Installation

From PyPI

pip install rawtherapee-mcp-server

From source

git clone https://github.com/lucamarien/rawtherapee-mcp-server
cd rawtherapee-mcp-server
pip install -e ".[dev]"

Client Configuration

Claude Desktop

The RawTherapee CLI path is auto-detected on most systems. Set RT_CLI_PATH if auto-detection fails or RawTherapee is in a non-standard location.

Windows (%APPDATA%\Claude\claude_desktop_config.json)

{
  "mcpServers": {
    "rawtherapee": {
      "command": "uvx",
      "args": ["rawtherapee-mcp-server"],
      "env": {
        "RT_CLI_PATH": "C:\\Program Files\\RawTherapee\\5.11\\rawtherapee-cli.exe",
        "RT_OUTPUT_DIR": "D:\\Photos\\Processed"
      }
    }
  }
}

macOS (~/Library/Application Support/Claude/claude_desktop_config.json)

{
  "mcpServers": {
    "rawtherapee": {
      "command": "uvx",
      "args": ["rawtherapee-mcp-server"],
      "env": {
        "RT_OUTPUT_DIR": "/Users/you/Pictures/Processed"
      }
    }
  }
}

RT CLI is auto-detected at /Applications/RawTherapee.app/Contents/MacOS/rawtherapee-cli.

Linux (~/.config/Claude/claude_desktop_config.json)

{
  "mcpServers": {
    "rawtherapee": {
      "command": "uvx",
      "args": ["rawtherapee-mcp-server"],
      "env": {
        "RT_OUTPUT_DIR": "/home/you/Pictures/Processed"
      }
    }
  }
}

RT CLI is auto-detected at /usr/bin/rawtherapee-cli, /usr/local/bin/rawtherapee-cli, or /snap/bin/rawtherapee-cli.

Development (from source)

Use uv to run from the cloned repository:

{
  "mcpServers": {
    "rawtherapee": {
      "command": "uv",
      "args": ["--directory", "/path/to/rawtherapee-mcp-server", "run", "rawtherapee-mcp-server"],
      "env": {
        "RT_OUTPUT_DIR": "/home/you/Pictures/Processed"
      }
    }
  }
}

Claude Code

# Published package
claude mcp add rawtherapee -- uvx rawtherapee-mcp-server

# Development (from source)
claude mcp add rawtherapee -- uv --directory /path/to/rawtherapee-mcp-server run rawtherapee-mcp

Cursor

Add to .cursor/mcp.json in your project:

{
  "mcpServers": {
    "rawtherapee": {
      "command": "uvx",
      "args": ["rawtherapee-mcp-server"],
      "env": {
        "RT_CLI_PATH": "/usr/bin/rawtherapee-cli",
        "RT_OUTPUT_DIR": "/home/you/Pictures/Processed"
      }
    }
  }
}

Windsurf

Add to your Windsurf MCP configuration:

{
  "mcpServers": {
    "rawtherapee": {
      "command": "uvx",
      "args": ["rawtherapee-mcp-server"],
      "env": {
        "RT_CLI_PATH": "/usr/bin/rawtherapee-cli",
        "RT_OUTPUT_DIR": "/home/you/Pictures/Processed"
      }
    }
  }
}

Cline (VS Code)

Add to your Cline MCP settings:

{
  "mcpServers": {
    "rawtherapee": {
      "command": "uvx",
      "args": ["rawtherapee-mcp-server"],
      "env": {
        "RT_CLI_PATH": "/usr/bin/rawtherapee-cli",
        "RT_OUTPUT_DIR": "/home/you/Pictures/Processed"
      }
    }
  }
}

Note: Cline may not render inline images from tool responses. All text-based tools work normally.

Quick Start

After installation and client configuration, try this workflow:

1. "Analyze this photo" — analyze_image reads EXIF, computes histogram, generates a thumbnail, and returns processing recommendations
2. "Make it warmer with more contrast" — generate_pp3_profile creates a profile with warm white balance and contrast boost, preview_before_after shows the difference
3. "The shadows are too dark" — add_luminance_adjustment adds a shadow recovery spot, preview_with_adjustments shows the result
4. "Export for my phone" — process_raw with device_preset crops and processes at the right aspect ratio

Available Tools (37)

Discovery & Configuration (5)

Tool	Description
check_rt_status	Check RawTherapee installation, version, CLI path, and server configuration
list_templates	List all available PP3 templates (built-in and custom)
list_device_presets	List all device/format crop and resize presets
list_raw_files	Scan a directory for supported RAW files
list_output_files	List processed output files in the output directory

Metadata & Analysis (5)

Tool	Description
read_exif	Read EXIF metadata with structured processing recommendations
analyze_image	All-in-one analysis: EXIF + histogram + thumbnail + recommendations
batch_analyze	Analyze multiple images with EXIF, recommendations, and thumbnails
get_image_info	Get dimensions, format, file size with optional inline thumbnail
get_histogram	RGB histogram with per-channel statistics, clipping, and SVG visualization

Profile Management (8)

Tool	Description
generate_pp3_profile	Create a PP3 profile from base template + parameters + device preset
read_profile	Display PP3 profile contents in human-readable format
adjust_profile	Modify specific parameters in an existing profile
compare_profiles	Diff two profiles with optional visual A/B comparison
save_template	Save a profile as a reusable custom template
create_template_from_description	Create a template stub from natural language description
delete_template	Delete a custom template
interpolate_profiles	Blend two profiles by linear interpolation

Preview & Visualization (7)

Tool	Description
preview_raw	Quick preview JPEG with optional inline image return
preview_before_after	Side-by-side neutral vs. profile comparison
preview_exposure_bracket	Multiple EV stops rendered for exposure comparison
preview_white_balance	Multiple WB presets with Kelvin values
batch_preview	Thumbnails for multiple RAW files
preview_luminance_mask	Grayscale mask showing local adjustment coverage
preview_with_adjustments	Preview with all Locallab spots active

Processing & Export (4)

Tool	Description
process_raw	Process a RAW file to JPEG/TIFF/PNG with inline thumbnail
apply_template	Apply a template to process a RAW file with optional device preset
batch_process	Process multiple RAW files with the same profile
export_multi_device	Export one RAW optimized for multiple devices in one call

Crop & Device (3)

Tool	Description
adjust_crop_position	Reposition crop (left/center/right, top/center/bottom, or pixel offsets)
add_device_preset_tool	Create a custom device preset
delete_device_preset	Delete a custom device preset

Local Adjustments (5)

Tool	Description
add_luminance_adjustment	Add luminance-based local adjustment (shadows/midtones/highlights/custom)
list_local_adjustments	List all Locallab spots in a profile
adjust_local_spot	Modify an existing Locallab spot
remove_local_adjustment	Remove a Locallab spot
apply_local_preset	Apply a predefined local adjustment preset with intensity scaling

Built-in Resources

PP3 Templates (5)

Template	Description
neutral	Minimal processing, camera white balance, basic sharpening
warm_portrait	Warm tones (5800K), gentle contrast, skin-friendly saturation
moody_cinematic	Cool tones (5200K), lifted blacks, reduced saturation, film look
vivid_pet	Warm tones (5600K), boosted saturation and vibrance, strong sharpening
bw_classic	Black & white via channel mixer, high contrast, strong sharpening

Device Presets (19)

• Mobile (7): Samsung Galaxy S26 Ultra, Galaxy S25 Ultra, iPhone 16 Pro Max, iPhone 16, Google Pixel 9 Pro, generic 9:16, generic 9:19.5
• Desktop (5): 4K UHD (3840x2160), WQHD (2560x1440), Full HD (1920x1080), Ultrawide 21:9 (3440x1440), Dual 4K 32:9 (7680x2160)
• Photo Formats (7): 3:2 (35mm), 4:3, 16:9, 1:1 (square), 5:4, 4:5 (Instagram portrait), 2:3 (portrait 35mm)

Custom presets can be added via add_device_preset_tool and persist across sessions.

Local Adjustment Presets (7)

Preset	Description
shadow_recovery	Brighten shadows without affecting highlights
highlight_protection	Compress highlights to recover detail
split_tone_warm_cool	Warm shadows, cool highlights
midtone_contrast	Add contrast to midtones only
shadow_desaturation	Desaturate shadow areas for a clean look
amoled_optimize	High contrast and deep blacks for AMOLED displays
hdr_natural	Natural HDR look with lifted shadows and compressed highlights

Presets accept an intensity parameter (50 = default, 25 = half, 100 = double).

Environment Variables

Variable	Default	Description
RT_CLI_PATH	Auto-detect	Path to rawtherapee-cli binary
RT_OUTPUT_DIR	~/Pictures/rawtherapee-mcp-output	Default output directory
RT_PREVIEW_DIR	OS temp dir	Preview image directory
RT_CUSTOM_TEMPLATES_DIR	./custom_templates	Custom PP3 templates directory
RT_PREVIEW_MAX_WIDTH	1200	Max preview width in pixels
RT_JPEG_QUALITY	95	Default JPEG quality (1-100)
RT_LOG_LEVEL	WARNING	Logging level (DEBUG, INFO, WARNING, ERROR)

See .env.example for a documented configuration template.

Known Limitations

• RawTherapee CLI must be installed separately — it is not a Python package and cannot be installed via pip
• stdio transport only — designed for local desktop use, no HTTP/SSE server mode
• RT 5.12 crop+resize bug — RawTherapee 5.12 silently ignores Crop when Resize is also enabled in the same PP3 profile; the server applies a crop-only workaround automatically
• 1MB MCP tool response limit — preview resolution is managed to stay within Claude Desktop's response size limit
• No pixel-level editing — no retouching, object removal, frequency separation, or content-aware fill
• No multi-image compositing — no HDR merge, panorama stitching, or focus stacking
• Luminance masks are tonal only — no spatial or subject-aware masking
• Integration tests require a RawTherapee installation and are skipped by default

Troubleshooting

RawTherapee not found:

• Run check_rt_status to see detection details
• Set RT_CLI_PATH to the full path of rawtherapee-cli:
  • Windows: C:\Program Files\RawTherapee\5.11\rawtherapee-cli.exe
  • macOS: /Applications/RawTherapee.app/Contents/MacOS/rawtherapee-cli
  • Linux: /usr/bin/rawtherapee-cli

Paths with spaces on Windows:

• Always use the full path in RT_CLI_PATH, including quotes if your shell requires them
• Environment variables in MCP client config JSON do not need extra escaping

Preview images too large:

• Reduce RT_PREVIEW_MAX_WIDTH (default: 1200)
• Preview tools auto-thumbnail to stay within the 1MB response limit

Server not responding:

• Verify the entry in your MCP client config is correct
• Restart your MCP client after config changes
• Set RT_LOG_LEVEL=DEBUG to see detailed logs on stderr

Docker

docker build -t rawtherapee-mcp-server .
docker run -i --rm \
  -v /path/to/photos:/photos \
  -v /path/to/output:/output \
  -e RT_OUTPUT_DIR=/output \
  rawtherapee-mcp-server

Development

See docs/DEVELOPMENT.md for full setup instructions.

git clone https://github.com/lucamarien/rawtherapee-mcp-server
cd rawtherapee-mcp-server
pip install -e ".[dev]"
make validate    # lint + format + typecheck + test + security + audit

Testing

# Unit tests (mocked, no RawTherapee required)
pytest -v

# Integration tests (requires RawTherapee installation)
pytest -m integration -v

MCP Inspector

npx @modelcontextprotocol/inspector uv run rawtherapee-mcp

Contributing

See CONTRIBUTING.md for development guidelines, coding standards, and PR checklist.

License

MIT