This record as markdown: /tools/io-tinyfn-tinyfn/darken-color.md
What darken_color does on TinyFn
AI agents call darken_color 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 |
|---|---|---|---|
amount | integer | — | Amount to darken (0-100) |
hex_color | string | Yes | Hex color to darken |
Parameters from the server's own tool schema.
Why darken_color is rated Low
This is a utility function that performs a mathematical color transformation based on input parameters. It retrieves/computes a result without side effects, modifying no external state, creating no records, and executing no code or commands. It belongs in the Read category as a computational transformation tool.
From the tool's definition Tool name 'darken_color' and description 'Darken a color by a percentage' indicate a pure color transformation utility. No data is created, modified, deleted, or persisted. The operation is deterministic (pure function) and read-only in nature.
Attacks that exploit this kind of access
The rule that runs darken_color 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 darken_color, this is the rule to start with:
darken_color 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 darken_color call is checked against it from then on.
Questions about darken_color
Darken a color by a percentage. It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
darken_color accepts 2 parameters: amount, 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 darken_color: 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.
darken_color 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 darken_color 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 darken_color. 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.
darken_color 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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