discover_tools
AI agents call discover_tools to retrieve information from Homeassistant without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool appears to query or list available tools/capabilities in the Home Assistant MCP server. Without a description, confidence is moderate, but the name strongly suggests a non-destructive discovery operation typical of Read category. Discovery tools have minimal blast radius as they only retrieve information about available functionality without modifying or executing operations.
From the tool's definition Tool name 'discover_tools' suggests discovery/enumeration of available tools or capabilities, which is a read operation with no side effects.
Attacks that exploit this kind of access
discover_tools. It is categorised as a Read tool in the Homeassistant MCP Server, which means it retrieves data without modifying state.
Register the Homeassistant MCP server in PolicyLayer and add a rule for discover_tools: 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 Homeassistant. Nothing to install.
discover_tools 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 discover_tools 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 discover_tools. 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.
discover_tools is provided by the Homeassistant MCP server (robbrad/homeassistant-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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