Contrast Checker Mcp
This server gives Claude WCAG 2.1 contrast checking tools so it can verify color accessibility, compute ratios, and suggest compliant alternatives. It exposes three tools: check_contrast for ratios and pass/fail against AA/AAA thresholds, suggest_accessible_color to fix failing pairs while preserving hue, and parse_color for format conversion. It handles hex, rgb, hsl, named colors, and alpha transparency with proper compositing. Calculations match WebAIM's checker exactly, including the 0.03928 sRGB threshold and truncated ratios. Useful when building UIs, auditing designs, or having Claude generate accessible color schemes without leaving the conversation.
- tools
- 3
- transport
- STDIO
- last updated
- Feb 25, 2026
Tools
3 toolsPublic tool metadata for what this MCP can expose to an agent.
check_contrastCheck the contrast ratio between two colors and evaluate WCAG 2.1 compliance.
Check the contrast ratio between two colors and evaluate WCAG 2.1 compliance.
No parameter schema in public metadata yet.
suggest_accessible_colorSuggest a replacement color that meets a WCAG contrast target, keeping the hue as close to the original as possible.
Suggest a replacement color that meets a WCAG contrast target, keeping the hue as close to the original as possible.
No parameter schema in public metadata yet.
parse_colorParse a color string and return it in multiple formats.
Parse a color string and return it in multiple formats.
No parameter schema in public metadata yet.
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contrast-checker-mcp
An MCP server that provides color contrast checking tools for AI assistants. Verify WCAG 2.1 accessibility compliance, compute contrast ratios with alpha transparency support, and get accessible color suggestions — all via the standard Model Context Protocol.
Contrast calculations match WebAIM's contrast checker — including alpha compositing, WCAG 0.03928 sRGB threshold, and truncated (not rounded) ratios.
Tools
check_contrast
Check the contrast ratio between two colors and evaluate WCAG 2.1 compliance.
Inputs:
foreground— Foreground color (e.g.#333,rgb(0,0,0),rgba(0,0,0,0.5),navy)background— Background color (e.g.#fff,rgb(255,255,255),white)
Output: Contrast ratio, WCAG 2.1 pass/fail results (AA normal, AA large, AAA normal, AAA large), parsed color values. When the foreground has alpha, shows the effective composited color used for the calculation.
suggest_accessible_color
Suggest a replacement color that meets a WCAG contrast target, keeping the hue as close to the original as possible.
Details
- Repository
- github.com/ogsingh/contrast-checker-mcp
- Package
contrast-checker-mcp- Transport
- STDIO
- Registry
- MCP registry, active