clean_mqtt
Remove stale MQTT discovery entries for an ESPHome device (MQTT mode only).
This record as markdown: /tools/fistacho-ha-nexus-agent/clean-mqtt.md
What clean_mqtt does on Ha Nexus Agent
AI agents call clean_mqtt to permanently remove resources in Ha Nexus Agent, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Why clean_mqtt is rated Critical
This tool deletes MQTT discovery entries, which are configuration state that cannot be automatically recovered once removed. While the scope is limited to 'stale' entries for a specific ESPHome device, deletion of discovery entries could break device communication or require manual reconfiguration. The 'Remove' action is irreversible without external backup or MQTT message replay.
From the tool's definition Tool name 'clean_mqtt' combined with description 'Remove stale MQTT discovery entries' — the verb 'Remove' indicates irreversible deletion of MQTT configuration data.
Attacks that exploit this kind of access
The rule that runs clean_mqtt safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Ha Nexus Agent, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For clean_mqtt, this is the rule to start with:
clean_mqtt is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect Ha Nexus Agent, apply this rule, and every clean_mqtt call is checked against it from then on.
Questions about clean_mqtt
Remove stale MQTT discovery entries for an ESPHome device (MQTT mode only). It is categorised as a Destructive tool in the Ha Nexus Agent MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Ha Nexus Agent MCP server in PolicyLayer and add a rule for clean_mqtt: 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 Ha Nexus Agent. Nothing to install.
clean_mqtt is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the clean_mqtt 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 clean_mqtt. 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.
clean_mqtt is provided by the Ha Nexus Agent MCP server (fistacho/ha-nexus-agent). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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