debug_version

THE RISK

Low Risk

Why debug_version needs a policy

This tool retrieves version and debug metadata about the MCP server itself. It performs no side effects, makes no changes to packages or system state, and executes no external operations. It is a simple query/inspection operation typical of diagnostic tools.

From the tool's definition Tool name is 'debug_version' and description states 'Get debug information about the running MCP server version' — purely informational retrieval with no modification or execution capability.

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

POLICY

How to control debug_version

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

policy.json

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

debug_version 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 Npmplus — 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

More Npmplus tools

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All 16 Npmplus tools →

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 debug_version

What does the debug_version tool do? +

Get debug information about the running MCP server version. It is categorised as a Read tool in the Npmplus MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on debug_version? +

Register the Npmplus MCP server in PolicyLayer and add a rule for debug_version: 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 Npmplus. Nothing to install.

What risk level is debug_version? +

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

Can I rate-limit debug_version? +

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

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

debug_version is provided by the Npmplus MCP server (shacharsol/js-package-manager-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Npmplus tool call.

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

CHECK YOUR STACK →