# Color Companion (remote · color-companion.gumballtools.com)

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

- Trust score: 76/100 (medium)
- Change this week: +4
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-25

## Components

- remote · `color-companion.gumballtools.com`: 76/100 (this document), [markdown](https://verifymcp.io/servers/com-gumballtools-color-companion/api-mcp.md), [page](https://verifymcp.io/servers/com-gumballtools-color-companion/api-mcp)

## Channel facts

- Endpoint: `https://color-companion.gumballtools.com/api/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.1.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-09-25.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 1 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 72/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 398 tokens (~398/item across 1 items; 1 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 67/100
  - Stability observed for 20 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 1 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 1 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the Color Companion MCP server?

Color Companion is a hosted endpoint at https://color-companion.gumballtools.com/api/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

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

### Cursor

```json
{
  "mcpServers": {
    "com-gumballtools-color-companion": {
      "url": "https://color-companion.gumballtools.com/api/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "com-gumballtools-color-companion": {
      "type": "http",
      "url": "https://color-companion.gumballtools.com/api/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.com-gumballtools-color-companion]
url = "https://color-companion.gumballtools.com/api/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-gumballtools-color-companion": {
      "type": "remote",
      "url": "https://color-companion.gumballtools.com/api/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-gumballtools-color-companion --url 'https://color-companion.gumballtools.com/api/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-gumballtools-color-companion:
    url: "https://color-companion.gumballtools.com/api/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "com-gumballtools-color-companion": {
      "Transport": "http",
      "Url": "https://color-companion.gumballtools.com/api/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add com-gumballtools-color-companion -t streamable-http -u 'https://color-companion.gumballtools.com/api/mcp'
```

### Other

```json
{
  "mcpServers": {
    "com-gumballtools-color-companion": {
      "type": "http",
      "url": "https://color-companion.gumballtools.com/api/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-09-25 (score 76, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-23 (score 75, +1)

No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-21 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 50 to 53. That category is still filling its 30-day observation window: 15 days of observed history at the previous scan, 16 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-19 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 43 to 47. That category is still filling its 30-day observation window: 13 days of observed history at the previous scan, 14 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-17 (score 72, +1)

No change was recorded against any check on this day. Stability & Change Management went from 37 to 40. That category is still filling its 30-day observation window: 11 days of observed history at the previous scan, 12 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-15 (score 71, +1)

No change was recorded against any check on this day. Stability & Change Management went from 30 to 33. That category is still filling its 30-day observation window: 9 days of observed history at the previous scan, 10 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-13 (score 70, +1)

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-10 (score 69, +1)

No change was recorded against any check on this day. Stability & Change Management went from 13 to 17. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 5 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (1)

### `analyse_color` (~398 tokens)

Convert a colour and find its harmonies

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.

Input parameters:

- `color` (string, required): A colour in any common notation: hex ("#3b82f6" or "3b82f6", 3/4/6/8 digits), rgb(), hsl(), oklch(), a CSS colour name ("rebeccapurple"), or "transparent".

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-gumballtools-color-companion/api-mcp#diagnostics

## Score history

- 2026-09-25: 76
- 2026-09-24: 75
- 2026-09-23: 75
- 2026-09-22: 74
- 2026-09-21: 74
- 2026-09-20: 73
- 2026-09-19: 73
- 2026-09-18: 72
- 2026-09-17: 72
- 2026-09-16: 71
- 2026-09-15: 71
- 2026-09-14: 70
- 2026-09-13: 70
- 2026-09-12: 69
- 2026-09-11: 69
- 2026-09-10: 69
- 2026-09-09: 68
- 2026-09-08: 68
- 2026-09-07: 67
- 2026-09-06: 67
- 2026-09-05: 66

## Common questions

### What is the Color Companion MCP server?

Color Companion is an MCP server listed in the public MCP registry as com.gumballtools/color-companion. Convert colours between hex, RGB, HSL, OKLCH and CMYK, and compute harmonies. This page covers its hosted endpoint (https://color-companion.gumballtools.com/api/mcp).

### Is the Color Companion MCP server safe to use?

Color Companion scores 76 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the Color Companion MCP server expose?

Color Companion exposes 1 tool: analyse_color. Their descriptions and schemas cost roughly 398 tokens of context every time the server is loaded.

### Does the Color Companion MCP server require authentication?

No. We connected to Color Companion without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the Color Companion MCP server still maintained?

Color Companion is still listed as active in the MCP registry. We last reached this channel on 25 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://color-companion.gumballtools.com/api/mcp
- Repository: https://github.com/bwalvoord/gumball
- Website: https://color-companion.gumballtools.com/
- Changelog RSS feed: https://verifymcp.io/servers/com-gumballtools-color-companion/api-mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-gumballtools-color-companion/api-mcp.json
- HTML version of this page: https://verifymcp.io/servers/com-gumballtools-color-companion/api-mcp