This record as markdown: /tools/io-github-kivanccakmak-yaver/npm-versions.md
What npm_versions does on Yaver
AI agents call npm_versions to retrieve information from Yaver without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
package | string | Yes |
Parameters from the server's own tool schema.
Why npm_versions is rated Low
This tool queries npm package registry data to list available versions. It performs no writes, deletions, code execution, or financial operations. The blast radius of misuse is minimal—an agent could only retrieve package version information already public on npm registries. This is a straightforward Read category tool with low severity.
From the tool's definition Tool name 'npm_versions' and description 'List versions of an npm package' indicate a read-only query operation that retrieves package metadata without modification or side effects.
Attacks that exploit this kind of access
The rule that runs npm_versions safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Yaver, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For npm_versions, this is the rule to start with:
npm_versions is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Yaver, apply this rule, and every npm_versions call is checked against it from then on.
Questions about npm_versions
List versions of an npm package. It is categorised as a Read tool in the Yaver MCP Server, which means it retrieves data without modifying state.
npm_versions accepts 1 parameter: package. Required: package. The full parameter table on this page comes from the server's own tool schema.
Register the Yaver MCP server in PolicyLayer and add a rule for npm_versions: 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 Yaver. Nothing to install.
npm_versions 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_versions 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_versions. 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_versions is provided by the Yaver MCP server (yaver-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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