contrast_ratio
Calculate contrast ratio between two colors (WCAG).
This record as markdown: /tools/io-tinyfn-tinyfn/contrast-ratio.md
What contrast_ratio does on TinyFn
AI agents call contrast_ratio to retrieve information from TinyFn without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
color1 | string | Yes | First hex color |
color2 | string | Yes | Second hex color |
Parameters from the server's own tool schema.
Why contrast_ratio is rated Low
This is a read-only utility that retrieves or computes information (contrast ratio per WCAG standards) based on input parameters without modifying any state, creating, deleting, or executing external operations. It falls clearly into the Read category with low severity since misuse poses no meaningful risk to systems or data.
From the tool's definition Tool calculates and returns contrast ratio between two colors—a pure computation with no side effects, data modification, or external operations. Description indicates 'calculate' which is deterministic analysis only.
Attacks that exploit this kind of access
The rule that runs contrast_ratio safely
PolicyLayer is an MCP gateway: it sits between your AI agents and TinyFn, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For contrast_ratio, this is the rule to start with:
contrast_ratio is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect TinyFn, apply this rule, and every contrast_ratio call is checked against it from then on.
Questions about contrast_ratio
Calculate contrast ratio between two colors (WCAG). It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
contrast_ratio accepts 2 parameters: color1, color2. Required: color1, color2. The full parameter table on this page comes from the server's own tool schema.
Register the TinyFn MCP server in PolicyLayer and add a rule for 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 TinyFn. Nothing to install.
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 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 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.
contrast_ratio is provided by the TinyFn MCP server (https://api.tinyfn.io/mcp/all/). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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