Rnv Color MCP

What RNVizion/rnv-color-mcp MCP server does

RNVizion/rnv-color-mcp MCP server exposes a color-processing workflow through MCP over Streamable HTTP. It handles digital and subtractive color operations, generates common harmony schemes, compares perceptual differences, checks accessible contrast, and stores named palettes for later retrieval. It also includes exact text case transformations as a separate utility.

Color inputs can be hexadecimal values, CSS color names, RNV brand names, or references to stored palettes. Palette references may identify the whole palette or a specific swatch, such as the second item in a named palette. Brand names take precedence when they collide with CSS names, while a css: prefix selects the CSS interpretation. Unrecognized names are rejected rather than approximated.

How it works

The hosted deployment is available at https://rnvizion-rnv-color-mcp.hf.space/mcp. An MCP client connects to that URL and sends natural-language requests that the model maps to server tools. The public deployment has authentication disabled, so no token or credential is needed for the connection.

Mixing supports up to 12 colors. Available modes include RGB, HSV, LAB, CMY, RYB, and paint mixing based on Kubelka-Munk pigment calculations. Format conversion covers hex, RGB, HSV, HSL, and LAB. Harmony generation supports complementary, analogous, triadic, split-complementary, tetradic or square, monochromatic, and compound schemes.

The server separates read-only operations from palette mutation when optional authentication is enabled. The read scope covers eight read-only tools, while write is required for save_palette. Tools outside a token's scope are hidden from the tool list.

Tools and capabilities

RNVizion/rnv-color-mcp MCP server includes these capabilities:

• mix_colors for multi-color blending in six supported modes.
• convert_color for conversions among five color representations.
• generate_harmony for seven harmony patterns.
• color_difference using CIEDE2000 or CIE76 Delta-E calculations.
• contrast_check for WCAG ratios and AA or AAA results.
• transform_text for 11 exact case transformations.
• save_palette, list_palettes, and get_palette for named palette storage and retrieval.

Setup and configuration

The hosted endpoint can be added as a custom connector in Claude by opening Settings, choosing Connectors, selecting Add custom connector, and entering the MCP URL. The README also describes running a local copy with pip install -r requirements.txt, followed by python server.py; the default port is 7860 unless PORT is set.

For durable palette storage in a self-hosted deployment, configure HF_TOKEN and a writable Hugging Face Dataset. Without that setup, saved palettes remain in process memory and disappear when the container restarts.

Optional authentication is enabled with RNV_AUTH=1, true, yes, or on. An enabled deployment must provide either RNV_AUTH_JWKS_URI or RNV_AUTH_PUBLIC_KEY, along with the expected issuer and audience settings. RNV_AUTH_BASE_URL supplies the server base URL without /mcp.

Limitations and notes

The canonical service is hosted and may differ from independently rebuilt copies. Self-hosted deployments need appropriate outbound network access for capabilities that fetch data. The color engine is dependency-free, but the server layer uses FastMCP. The README states that authentication tests run in CI, while the color engine itself is not covered by automated tests.