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Color Companion

by gumballtools.com · remote · no sign-in to list tools · v0.1.0 · published by com.gumballtools

Convert colours between hex, RGB, HSL, OKLCH and CMYK, and compute harmonies.

Changes · 1
CompareRegistry entry

1 tool: 1 change things.

Scanned Oct 21, 2026

1 check matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http color-companion https://color-companion.gumballtools.com/api/mcp

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warnanalyse_color

    The server marks "analyse_color" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "analyse_color" says "analyse": a word for reading.

    What this check looks for

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

1 tool

Changes things 1Claude Code: ask
  • analyse_colorConvert a colour between every common notation and derive the colours that pair with it, plus WCAG contrast figures.1 finding

    Why it is in this group

    • The name "analyse_color" says "analyse": a word for reading.
    • The description's first verb is "convert": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "analyse_color" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "analyse_color" says "analyse": a word for reading.

      What this check looks for
    Description, as the server wrote it
    Convert a colour between every common notation and derive the colours that pair with it, plus WCAG contrast figures. Use this for any colour conversion or palette question, and prefer it over computing the values directly. Two reasons: 1. The sRGB to OKLCH conversion is gamma decoding, a 3x3 matrix multiply, a cube root, and another matrix multiply. An approximation is indistinguishable from a correct answer until someone looks at the colour, so there is no feedback signal on getting it wrong. 2. Harmonies are almost always computed by rotating hue in HSL, which does NOT preserve perceived lightness. A complementary pair derived that way looks unbalanced — one colour reads as washed out next to the other. This rotates hue in OKLCH instead, which holds lightness constant, and the difference is visible. Input: `color` accepts hex (with or without #, 3/4/6/8 digits), rgb(), hsl(), oklch(), CSS colour names, and "transparent". Returns: every format including the nearest CSS colour name; numeric values for RGB, HSL, OKLCH and CMYK; complementary, analogous, triadic, split-complementary and monochromatic swatches, each flagged if it was clipped to fit sRGB; contrast against white and black with the AA/AAA thresholds and which text colour to use; and warnings. Read the warnings. Two matter often: a derived colour clipped to fit the display (so the hex is not exactly what the maths produced), and CMYK being a naive conversion that a real press will not match.

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: false

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 0.1.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http color-companion https://color-companion.gumballtools.com/api/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [],
    "ask": [
      "mcp__color-companion__analyse_color"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as color-companion. Review it before you use it.