AI agents call rule_of_72 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 |
|---|---|---|---|
rate | number | Yes | Annual interest rate (percentage) |
Parameters from the server's own tool schema.
This is a deterministic financial formula calculator (Rule of 72 is a quick mental math formula). It takes investment parameters as input and returns a calculated estimate of doubling time. It performs no mutations, no external operations, and does not execute actual financial transactions or create obligations. It is purely informational/computational, fitting the Read category.
From the tool's definition Tool name 'rule_of_72' and description 'Calculate time to double investment using Rule of 72' indicate a pure calculation utility that retrieves/computes a mathematical result without modifying any data, executing external operations, or committing financial…
Attacks that exploit this kind of access
Calculate time to double investment using Rule of 72. It is categorised as a Read tool in the TinyFn MCP Server, which means it retrieves data without modifying state.
rule_of_72 accepts 1 parameter: rate. Required: rate. 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 rule_of_72: 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.
rule_of_72 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 rule_of_72 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 rule_of_72. 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.
rule_of_72 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.
rule_of_72 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.
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