AI agents call npm_package_types to retrieve information from Npm Info without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only reads and reports metadata about npm packages—specifically whether TypeScript type definitions are present. It has no side effects, cannot modify any data, execute arbitrary code, or perform destructive operations. The potential for misuse is minimal as the worst outcome would be receiving incorrect information about type definitions, which would not cause system damage or compromise.
From the tool's definition Tool retrieves information about whether an npm package includes TypeScript type definitions. The description indicates it 'detects bundled types' and 'checks' for type definitions without any modification, creation, deletion, or execution of code.
Attacks that exploit this kind of access
Check whether an npm package ships TypeScript type definitions. Detects bundled types from three sources (in priority order): 1. \. It is categorised as a Read tool in the Npm Info MCP Server, which means it retrieves data without modifying state.
Register the Npm Info MCP server in PolicyLayer and add a rule for npm_package_types: 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 Npm Info. Nothing to install.
npm_package_types 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 npm_package_types 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 npm_package_types. 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.
npm_package_types is provided by the Npm Info MCP server (kongyo2/npm-info). 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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