Color Similarity SkillColor Similarity Skill

OnlineCredit Usage:1 per callTool:ColorSimilaritySkill

The tool

Color Similarity Calculator provides detailed color comparison using both RGB and HSL color spaces, calculating similarity percentages, color distances, and providing categorical similarity ratings.

Once your client is connected to the VerveKit MCP server, this appears in its tool list as ColorSimilaritySkill. It is read-only and open-world: it fetches, it never mutates anything on your side, so most clients will call it without asking you to confirm.

Tool call
{
  "name": "ColorSimilaritySkill",
  "arguments": {
    "color1": "FF5733",
    "color2": "FF6B47"
  }
}

What that looks like in a conversation

You don't name the tool — the model picks it. Asking about FF5733 in the terms this source covers is enough for it to reach for ColorSimilaritySkill on its own.

Connecting

One server URL covers every skill in the catalog, including this one. Authorization is OAuth — the client opens a browser once and there is no key to paste into a config file.

Client config
{
  "mcpServers": {
    "vervekit": {
      "url": "https://api.vervekit.com/v1/mcp"
    }
  }
}
Endpoint
https://api.vervekit.com/v1/mcp

Per-client setup — Claude Desktop, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made.

ArgumentTypeExampleDescription
color1RequiredstringFF5733First hex color value (with or without # prefix)
color2RequiredstringFF6B47Second hex color value (with or without # prefix)

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client can read fields without parsing prose. status is "ok" on success and error is null; a null field means the value wasn't available for that input, not that the call failed.

Result
{
  "status": "ok",
  "error": null,
  "data": {
    "color1": {
      "hex": "#FF5733",
      "rgb": {
        "r": 255,
        "g": 87,
        "b": 51
      },
      "hsl": {
        "h": 10.6,
        "s": 100,
        "l": 60
      }
    },
    "color2": {
      "hex": "#FF6B47",
      "rgb": {
        "r": 255,
        "g": 107,
        "b": 71
      },
      "hsl": {
        "h": 11.7,
        "s": 100,
        "l": 63.9
      }
    },
    "rgb_distance": 28.28,
    "rgb_similarity": 93.6,
    "hsl_similarity": 97.71,
    "overall_similarity": 95.65,
    "delta_e": 28.28,
    "hue_difference": 1.15,
    "saturation_difference": 0,
    "lightness_difference": 3.92,
    "similarity_category": "nearly identical",
    "are_identical": false
  }
}

Fields

Fields marked Premium need a paid plan. On a plan without them the key is absent rather than wrong, so a model never reasons over a substituted value.
FieldTypeExampleDescription
color1object{…}The first colour, in hex, RGB and HSL
color1.hexstring#FF5733First color in hexadecimal format representation
color1.rgbobject{…}First colour as red, green and blue channels
color1.rgb.rnumber255Red channel value for first color
color1.rgb.gnumber87Green channel value for first color
color1.rgb.bnumber51Blue channel value for first color
color1.hslobject{…}First colour as hue, saturation and lightness
color1.hsl.hnumber10.6Hue value for first color in degrees
color1.hsl.snumber100Saturation percentage for first color
color1.hsl.lnumber60Lightness percentage for first color
color2object{…}The second colour, in hex, RGB and HSL
color2.hexstring#FF6B47Second color in hexadecimal format representation
color2.rgbobject{…}Second colour as red, green and blue channels
color2.rgb.rnumber255Red channel value for second color
color2.rgb.gnumber107Green channel value for second color
color2.rgb.bnumber71Blue channel value for second color
color2.hslobject{…}Second colour as hue, saturation and lightness
color2.hsl.hnumber11.7Hue value for second color in degrees
color2.hsl.snumber100Saturation percentage for second color
color2.hsl.lnumber63.9Lightness percentage for second color
rgb_distancePremiumnumber28.28Euclidean distance between colors in RGB space
rgb_similarityPremiumnumber93.6Percentage similarity based on RGB color space
hsl_similarityPremiumnumber97.71Percentage similarity based on HSL color space
overall_similaritynumber95.65Combined similarity percentage from all algorithms
delta_ePremiumnumber28.28Delta E color difference metric for perceptual similarity
hue_differencePremiumnumber1.15Hue difference between colors in degrees
saturation_differencePremiumnumber0Saturation percentage difference between colors
lightness_differencePremiumnumber3.92Lightness percentage difference between colors
similarity_categorystringnearly identicalHuman readable category describing similarity level
are_identicalbooleanfalseBoolean indicating if colors are exactly identical

Failure modes

Errors come back as tool errors with a sentence the model can act on, not a bare status code.

StatusWhat it means
400 / 422The arguments didn't validate. The message names the offending one.
401The OAuth session is invalid or expired — reconnect the server.
403Out of credits. Not a bad key — the month's allowance is spent.
404This skill isn't part of VerveKit. Check the catalog.
429Brief rate limit. Retrying after a moment succeeds.

Other ways to use Color Similarity Skill

Set up Color Similarity Skill on VerveKit, or reach the same source a different way. Your VerveKit account and credits work on all of them — one key, one balance.

Call it as a REST APIOne HTTPS endpoint and an X-API-Key header, with SDKs for Node, Python and .NET.APIVerveReference →
Use it in Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheetsReference →
Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContextReference →

Frequently asked questions

Do I have to tell the agent to use ColorSimilaritySkill?

No. The tool's name and description are in the model's context once the server is connected, so it selects the tool when the question calls for it. Naming it explicitly works too and is useful when you want to force the call.

Does connecting the server expose every tool at once?

Yes — one connection lists the whole VerveKit catalog. Clients with a tool budget can usually filter the list; the credit cost is per call, so an unused tool costs nothing.

What does a call cost?

1 credit each time the tool actually runs. A model that reasons about the tool without calling it costs nothing.

Is there a REST version of this?

Yes — the same source is available as a plain HTTPS endpoint on APIVerve, linked above. Same data, same credits, same account.

What's Next?

Continue your journey with these recommended resources

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