[tools] Add check_color_contrast_tool for WCAG accessibility compliance #53
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Implements a comprehensive color contrast checker that validates color combinations against WCAG 2.1 accessibility standards. Key features: - Calculates contrast ratios using WCAG 2.1 algorithm - Supports multiple color formats (hex, rgb, rgba, named colors) - Validates against WCAG AA and AAA levels - Separate requirements for normal and large text - Provides actionable recommendations when contrast fails - Full luminance calculation with gamma correction The tool extends BaseTool for offline operation (no API calls). Uses the official WCAG 2.1 relative luminance and contrast ratio formulas to ensure accurate accessibility measurements. Color format support: - 3-digit, 6-digit, and 8-digit hex colors (#RGB, #RRGGBB, #RRGGBBAA) - RGB and RGBA functional notation - CSS named colors (black, white, red, blue, etc.) WCAG requirements: - AA: 4.5:1 (normal text), 3:1 (large text) - AAA: 7:1 (normal text), 4.5:1 (large text) Test coverage: 28 comprehensive test cases covering all features including maximum contrast, WCAG AA/AAA compliance, all color formats, error handling, default parameters, recommendations, and real-world color combinations. Documentation: Added comprehensive README documentation with parameters, color format support, WCAG requirements, return values, and example prompts. Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
mattpodwysocki
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Jan 9, 2026
…roduction prompt Adds comprehensive style quality validation capabilities: Skill: - Created mapbox-style-quality skill document (390+ lines) - Pre-production checklist and validation best practices - Guidance on expression validation, GeoJSON validation, and accessibility - Optimization strategies and workflow recommendations - Integration patterns for Git hooks, CI/CD, and code review Prompt: - Created prepare-style-for-production prompt - Orchestrates validation workflow using 5 quality tools: * validate_expression_tool - Validate expressions in filters/paint/layout * validate_geojson_tool - Validate GeoJSON sources * check_color_contrast_tool - WCAG accessibility compliance * optimize_style_tool - Remove redundancies and optimize * compare_styles_tool - Compare versions (implicit in workflow) - Configurable WCAG level (AA/AAA) and optional optimization skip - Generates comprehensive quality report with deployment readiness assessment Testing: - 15 test cases for PrepareStyleForProductionPrompt - All 386 tests passing - Updated prompt registry tests Documentation: - Updated README with new skill listing - Added prompt documentation with usage examples - Cross-referenced skill and prompt Related PRs: - PR #50: validate_geojson_tool - PR #51: validate_expression_tool - PR #52: compare_styles_tool - PR #53: check_color_contrast_tool - PR #54: optimize_style_tool Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
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Summary
Implements a comprehensive color contrast checker that validates color combinations against WCAG 2.1 accessibility standards.
Key Features
Implementation Details
BaseToolfor offline operation#RGB#RRGGBB#RRGGBBAArgb(r, g, b),rgba(r, g, b, a)black,white,red,blue, etc.WCAG 2.1 Requirements
Testing
All tests passing ✅
Documentation
Added comprehensive README documentation with:
Use Cases
This tool enables:
Related PRs
Part of the offline validation tools initiative:
🤖 Generated with Claude Code