fisher_f_variate
AI agents call fisher_f_variate to retrieve information from FortunaMCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves/generates random numerical values (a statistical sample from the Fisher F-distribution) without modifying, executing external operations, or deleting data. It is a pure read/query operation returning computed output. Severity is low because misuse produces only incorrect statistical results, not data loss, code execution, or financial harm.
From the tool's definition Tool named 'fisher_f_variate' on a server described as 'generating high-quality random values' using a 'C-extension' RNG.
Attacks that exploit this kind of access
fisher_f_variate. It is categorised as a Read tool in the FortunaMCP MCP Server, which means it retrieves data without modifying state.
Register the Fortuna MCP server in PolicyLayer and add a rule for fisher_f_variate: 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 FortunaMCP. Nothing to install.
fisher_f_variate 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 fisher_f_variate 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 fisher_f_variate. 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.
fisher_f_variate is provided by the Fortuna MCP server (siliconsociety/fortunamcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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