This record as markdown: /tools/io-github-kivanccakmak-yaver/port-check.md
What port_check does on Yaver
AI agents call port_check 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 |
|---|---|---|---|
port | integer | Yes | Port number to check |
Parameters from the server's own tool schema.
Why port_check is rated Low
This tool reads system information about port usage. It performs a diagnostic query with no side effects, no code execution, and no data modification. The only potential risk is information disclosure (learning which processes are bound to ports), which is minimal in a local development context and is essential for debugging network issues.
From the tool's definition Tool description states 'Check what process is using a specific port' — a query operation that retrieves information about system state without modification or execution.
Attacks that exploit this kind of access
The rule that runs port_check 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 port_check, this is the rule to start with:
port_check 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 port_check call is checked against it from then on.
Questions about port_check
Check what process is using a specific port. It is categorised as a Read tool in the Yaver MCP Server, which means it retrieves data without modifying state.
port_check accepts 1 parameter: port. Required: port. 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 port_check: 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.
port_check 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 port_check 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 port_check. 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.
port_check 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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