mcp_performance

THE RISK

Low Risk

Why mcp_performance needs a policy

This tool retrieves and displays observability metrics (call counts, error rates, tool usage statistics) about MCP server performance. It is purely a read/query operation with no side effects, data modification, or destructive actions. Misuse potential is minimal as it only surfaces existing telemetry data.

From the tool's definition Track MCP server performance: call counts, error rates, most used tools

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

POLICY

How to control mcp_performance

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

policy.json

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

mcp_performance 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 Claude Code Toolkit — 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

Related tools and policies

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Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about mcp_performance

What does the mcp_performance tool do? +

Track MCP server performance: call counts, error rates, most used tools. It is categorised as a Read tool in the Claude Code Toolkit MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on mcp_performance? +

Register the Claude Code Toolkit MCP server in PolicyLayer and add a rule for mcp_performance: 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 Claude Code Toolkit. Nothing to install.

What risk level is mcp_performance? +

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

Can I rate-limit mcp_performance? +

Yes. Add a rate_limit block to the mcp_performance 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 mcp_performance completely? +

Set action: deny in the PolicyLayer policy for mcp_performance. 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 mcp_performance? +

mcp_performance is provided by the Claude Code Toolkit MCP server (asifkibria/claude-code-toolkit). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Claude Code Toolkit tool call.

Start from Claude Code Toolkit, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →