AI agents call get_luminance to retrieve information from TinyFn without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
hex_color | string | Yes | Hex color |
Parameters from the server's own tool schema.
This is a deterministic mathematical function that computes and returns a color property value. It retrieves/calculates information without modifying state, creating resources, executing external code, deleting data, or moving money. It poses minimal security risk.
From the tool's definition Tool name 'get_luminance' and description 'Calculate relative luminance of a color' indicate a pure calculation/retrieval operation with no side effects.
Attacks that exploit this kind of access
Calculate relative luminance of a color. It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
get_luminance accepts 1 parameter: hex_color. Required: hex_color. 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 get_luminance: 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.
get_luminance 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 get_luminance 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 get_luminance. 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.
get_luminance 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.
get_luminance is one line of TinyFn's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
Teams ship this data inside their own products. See what a licence covers →