# Zovo Palette Lab

> WCAG contrast & palettes

- name: io.github.theluckystrike/contrast-checker
- version: 1.0.0
- connection class: R0 (autonomous)
- trust: 78/100 flags: no-repository
- quality: 91/100 (strong)
- owner: not claimed
- descriptor: https://api.protogrid.dev/v1/servers/io.github.theluckystrike%2Fcontrast-checker
- tools: https://api.protogrid.dev/v1/servers/io.github.theluckystrike%2Fcontrast-checker/tools

**An agent can connect right now, no human step.** Remote endpoint, no authentication, reachable on the last probe.

## Connection (mcpServers)

```json
{
  "mcpServers": {
    "contrast-checker": {
      "type": "http",
      "url": "https://contrast-checker.zovo.one/mcp"
    }
  }
}
```


## Trust

- hygiene: 80
- liveness: 100
- freshness: 100
- provenance: 40
- drivers: +website -thin-description +reachable +uptime-100% +updated-23d-ago -no-repository
- Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed.

## Quality 91/100 (strong)

### protocol: 75 (weight 25)

- warn `protocol.modern`: newest supported version is 2025-11-25; 2026-07-28 not supported, older versions are deprecated until 2027-07-28
- n/a `protocol.stateless`: only applies to 2026-07-28 servers
- pass `protocol.transport`: streamable HTTP
- n/a `protocol.list_ttl`: only applies to 2026-07-28 servers

### authorization: n/a (weight 15)

- n/a `auth.prm`, `auth.as_metadata`, `auth.cimd`: no remote uses OAuth
- n/a `auth.secret_in_url`: no templated URL

### tool hygiene: 100 (weight 30)

- pass `tools.descriptions`: every tool has a description
- pass `tools.description_length`: descriptions are concise
- pass `tools.schemas`: every tool has an object input schema
- pass `tools.annotations`: 3 of 3 tools declare readOnlyHint or destructiveHint
- pass `tools.directory_hints`: every tool declares readOnlyHint, destructiveHint, idempotentHint and openWorldHint
- pass `tools.token_cost`: about 1,245 tokens to load every tool
- pass `tools.api_dump`: tools are not a one-to-one API dump
- pass `tools.hidden_text`: no hidden text in tool names, descriptions, schemas or annotations

### stability: 100 (weight 15)

- pass `stability.changes`: no tool changes in 30 days
- pass `stability.rug_pull`: no tool changed its meaning under the same name
- pass `stability.new_links`: no tool change named a new site

### dependencies: n/a (weight 15)

- n/a `deps.known_vulns`, `deps.mcp_sdk_version`, `deps.resolvable`: no npm or PyPI package

- tools: 3, about 1,245 tokens to load them all
- tool set hash: 796f654f6784853142b556c02c99c6ef
- badge: [![protogrid quality](https://protogrid.dev/badge/io.github.theluckystrike/contrast-checker.svg)](https://protogrid.dev/servers/io.github.theluckystrike/contrast-checker)
- Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed.

### Tool changes

_No tool definition changes recorded._

## Remotes

- https://contrast-checker.zovo.one/mcp (streamable-http, auth none, reachable true, uptime30d 1)

## Packages

_none_

## Tools (3)

- `check_color_contrast`: Use this when the user wants to know whether a text, icon or border colour has enough contrast against a background: a WCAG contrast checker for one colour pair (e.g. "does white text on #F59E0B pass WCAG AA", "contrast ratio of #767676 on white", "what text color for this background"). Returns the computed WCAG 2.x ratio (truncated to 2 decimals, rounded down), AA/AAA results for normal text, large text and UI components, a verdict for a given font size, APCA Lc as draft information, and the nearest passing colours for AA and AAA (darker and lighter, same OKLCH hue and chroma). Accepts hex, 8-digit hex with alpha, rgb(), hsl(), hwb(), lab(), lch(), oklab(), oklch(), color(display-p3 ...) and CSS colour names; wide-gamut colours are clipped to sRGB with a note. Does not read colours from images or web pages, resolve CSS variables or currentColor, or check gradients as a whole (check each stop). For 3 or more colours use check_palette_contrast.
- `check_palette_contrast`: Use this when the user has a colour palette (2 to 12 colours) and wants to know which combinations are accessible: "check contrast of my color palette", "which of these colors can I use for text", "accessible color palette checker". Returns the full pairwise WCAG 2.x contrast matrix (ratios truncated, rounded down), which pairs pass AA/AAA for text or 3:1 for large text and UI, and a recommended text colour for each background (a palette colour that passes AA, otherwise black or white). Does not generate new colours; use generate_accessible_palette for a tonal scale and check_color_contrast for fixes to one pair.
- `generate_accessible_palette`: Use this when the user wants an accessible colour scale or palette built from one colour: "color palette generator from hex", "generate a 50-950 scale from #1E6FD9", "tailwind color palette generator", "accessible color palette for my website". Builds an 11-step 50-950 tonal scale in OKLCH with the base hue, where 50-400 pass AA with black text, 500 passes AA with both white and black text, 600 passes AA with white text and 700-950 pass AAA with white text, and each ratio is reported. Returns CSS custom properties and a Tailwind config as downloads. Does not pick colours by mood or brand meaning and does not extract palettes from images.