{"id":"color-contrast-wcag","version":"1.0.0","description":"Compute WCAG 2.x relative luminance, contrast ratio, and AA/AAA pass flags for two opaque sRGB colors.","supported_operations":["compute WCAG color contrast","check text color accessibility","calculate contrast ratio between colors","test WCAG AA contrast","test WCAG AAA contrast","compare foreground and background luminance","convert sRGB colors to relative luminance"],"unsupported_operations":["alpha compositing or translucent colors","APCA perceptual contrast","wide-gamut or non-sRGB colors"],"semantics":["Each color is exactly a #RRGGBB string or an object with integer r, g and b channels from 0 through 255; output hex is uppercase.","Relative luminance uses the WCAG 2.x sRGB transfer breakpoint 0.04045 and coefficients 0.2126, 0.7152 and 0.0722.","The contrast ratio is (lighter luminance + 0.05) / (darker luminance + 0.05); raw values determine thresholds before formatting.","Relative luminance strings have exactly six digits after the decimal point and contrast_ratio has exactly two, both rounded by ECMAScript Number toFixed.","AA thresholds are 4.5 for normal text and 3 for large text; AAA thresholds are 7 for normal text and 4.5 for large text.","Colors are opaque sRGB only; this tool performs neither alpha compositing nor APCA."],"limits":{"max_color_text_bytes":7},"pricing":{"status":"unpriced","charge_usd":null},"input_schema":{"type":"object","additionalProperties":false,"required":["foreground","background"],"properties":{"foreground":{"oneOf":[{"type":"string","minLength":7,"maxLength":7,"pattern":"^#[0-9A-Fa-f]{6}$"},{"type":"object","additionalProperties":false,"required":["r","g","b"],"properties":{"r":{"type":"integer","minimum":0,"maximum":255},"g":{"type":"integer","minimum":0,"maximum":255},"b":{"type":"integer","minimum":0,"maximum":255}}}]},"background":{"oneOf":[{"type":"string","minLength":7,"maxLength":7,"pattern":"^#[0-9A-Fa-f]{6}$"},{"type":"object","additionalProperties":false,"required":["r","g","b"],"properties":{"r":{"type":"integer","minimum":0,"maximum":255},"g":{"type":"integer","minimum":0,"maximum":255},"b":{"type":"integer","minimum":0,"maximum":255}}}]}}},"output_schema":{"type":"object","additionalProperties":false,"required":["foreground","background","contrast_ratio","passes"],"properties":{"foreground":{"type":"object","additionalProperties":false,"required":["hex","r","g","b","relative_luminance"],"properties":{"hex":{"type":"string","minLength":7,"maxLength":7,"pattern":"^#[0-9A-F]{6}$"},"r":{"type":"integer","minimum":0,"maximum":255},"g":{"type":"integer","minimum":0,"maximum":255},"b":{"type":"integer","minimum":0,"maximum":255},"relative_luminance":{"type":"string","pattern":"^(0|1)\\.[0-9]{6}$"}}},"background":{"type":"object","additionalProperties":false,"required":["hex","r","g","b","relative_luminance"],"properties":{"hex":{"type":"string","minLength":7,"maxLength":7,"pattern":"^#[0-9A-F]{6}$"},"r":{"type":"integer","minimum":0,"maximum":255},"g":{"type":"integer","minimum":0,"maximum":255},"b":{"type":"integer","minimum":0,"maximum":255},"relative_luminance":{"type":"string","pattern":"^(0|1)\\.[0-9]{6}$"}}},"contrast_ratio":{"type":"string","pattern":"^(?:[1-9]|1[0-9]|2[01])\\.[0-9]{2}$"},"passes":{"type":"object","additionalProperties":false,"required":["aa_normal","aa_large","aaa_normal","aaa_large"],"properties":{"aa_normal":{"type":"boolean"},"aa_large":{"type":"boolean"},"aaa_normal":{"type":"boolean"},"aaa_large":{"type":"boolean"}}}}},"examples":[{"input":{"foreground":"#000000","background":"#FFFFFF"},"output":{"foreground":{"hex":"#000000","r":0,"g":0,"b":0,"relative_luminance":"0.000000"},"background":{"hex":"#FFFFFF","r":255,"g":255,"b":255,"relative_luminance":"1.000000"},"contrast_ratio":"21.00","passes":{"aa_normal":true,"aa_large":true,"aaa_normal":true,"aaa_large":true}}},{"input":{"foreground":{"r":119,"g":119,"b":119},"background":"#ffffff"},"output":{"foreground":{"hex":"#777777","r":119,"g":119,"b":119,"relative_luminance":"0.184475"},"background":{"hex":"#FFFFFF","r":255,"g":255,"b":255,"relative_luminance":"1.000000"},"contrast_ratio":"4.48","passes":{"aa_normal":false,"aa_large":true,"aaa_normal":false,"aaa_large":false}}}],"execute_url":"/v1/tools/color-contrast-wcag/versions/1.0.0/execute"}