This record as markdown: /tools/io-tinyfn-tinyfn/calculate-discount.md
What calculate_discount does on TinyFn
AI agents call calculate_discount 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 |
|---|---|---|---|
original_price | number | Yes | Original price |
discount_percent | number | Yes | Discount percentage |
Parameters from the server's own tool schema.
Why calculate_discount is rated Low
This is a deterministic math/calculation tool on a server described as providing '500+ deterministic tools for AI agents: math, conversion, validation.' It computes a discounted price value locally without moving money, modifying data, or triggering external operations. Consistent with sibling tools like absolute_value, add, acres_to_hectares — all pure computations.
From the tool's definition 'Calculate discounted price' — performs a mathematical computation (price × discount rate) with no side effects
Attacks that exploit this kind of access
The rule that runs calculate_discount 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 calculate_discount, this is the rule to start with:
calculate_discount 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 calculate_discount call is checked against it from then on.
Questions about calculate_discount
Calculate discounted price. It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
calculate_discount accepts 2 parameters: original_price, discount_percent. Required: original_price, discount_percent. 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 calculate_discount: 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.
calculate_discount 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 calculate_discount 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 calculate_discount. 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.
calculate_discount 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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