list_ports
AI agents call list_ports to retrieve information from Arduino MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool appears to list available serial ports that Arduino boards connect to, which is a non-destructive information retrieval operation. No side effects, modifications, or external state changes are implied. The empty description lowers confidence slightly, but the tool name and sibling context make the read classification highly probable.
From the tool's definition Tool name 'list_ports' indicates retrieval/enumeration of serial ports or communication endpoints. No description provided, but naming convention and context within Arduino CLI tools (alongside list_connected_boards, compile_sketch, install_library) strongly…
Attacks that exploit this kind of access
list_ports. It is categorised as a Read tool in the Arduino MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Arduino MCP Server MCP server in PolicyLayer and add a rule for list_ports: 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 Arduino MCP Server. Nothing to install.
list_ports 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 list_ports 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 list_ports. 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.
list_ports is provided by the Arduino MCP Server MCP server (niradler/arduino-mcp). 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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