eigenvalues

THE RISK

Low Risk

Why eigenvalues needs a policy

Eigenvalue computation is a read-only mathematical operation that retrieves derived numerical data from an input matrix without creating, modifying, deleting, or executing anything. The tool produces no side effects and the result depends solely on the mathematical properties of the input matrix.

From the tool's definition Tool 'eigenvalues' computes and returns eigenvalues of a matrix. The description explicitly states it 'Returns an array of numbers' with no mention of modifying state, executing external operations, or triggering side effects.

Documented attack patterns abuse exactly the kind of access eigenvalues gives an agent:

POLICY

How to control eigenvalues

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Calc Tools, and nothing reaches the server without passing your rules. This is the rule we recommend for eigenvalues:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "eigenvalues": {}
  }
}

eigenvalues is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register MCP Calc Tools — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
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Rate Limiting MCP Tool Calls: A Practical Guide →
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FAQ

Questions about eigenvalues

What does the eigenvalues tool do? +

Find the eigenvalues of a square matrix. Returns an array of numbers. Example: eigenvalues([[4,1],[2,3]]) -> [5, 2]. It is categorised as a Read tool in the MCP Calc Tools MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on eigenvalues? +

Register the MCP Calc Tools MCP server in PolicyLayer and add a rule for eigenvalues: 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 MCP Calc Tools. Nothing to install.

What risk level is eigenvalues? +

eigenvalues is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit eigenvalues? +

Yes. Add a rate_limit block to the eigenvalues 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.

How do I block eigenvalues completely? +

Set action: deny in the PolicyLayer policy for eigenvalues. 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.

What MCP server provides eigenvalues? +

eigenvalues is provided by the MCP Calc Tools MCP server (nbiish/mcp-calc-tools). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP Calc Tools tool call.

Start from MCP Calc Tools, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →