AI agents call color_contrast_ratio to retrieve information from UnClick without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
background | string | Yes | |
foreground | string | Yes |
Parameters from the server's own tool schema.
This tool performs a calculation or lookup of contrast ratio values based on input colors. It retrieves data (the contrast ratio result) without creating, modifying, deleting, or executing external operations. No destructive, financial, or code execution capabilities are present. This is a pure Read operation with minimal security risk.
From the tool's definition Tool name 'color_contrast_ratio' and description 'Check the contrast ratio between two colors' indicate a query operation that retrieves computed contrast information without side effects.
Attacks that exploit this kind of access
Check the contrast ratio between two colors. It is categorised as a Read tool in the UnClick MCP Server, which means it retrieves data without modifying state.
color_contrast_ratio accepts 2 parameters: background, foreground. Required: background, foreground. The full parameter table on this page comes from the server's own tool schema.
Register the UnClick MCP server in PolicyLayer and add a rule for color_contrast_ratio: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches UnClick. Nothing to install.
color_contrast_ratio is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the color_contrast_ratio rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for color_contrast_ratio. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
color_contrast_ratio is provided by the UnClick MCP server (@unclick/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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