AI agents invoke home_robot to trigger actions in Opentrons MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
Homing a robot causes physical mechanical movement of axes or pipettes to a reference position. This is an external operation with physical effects on lab equipment, fitting the Execute category. Misuse could disrupt ongoing operations or cause collisions, warranting medium severity.
From the tool's definition Home robot axes or specific pipette — triggers physical movement of the robot hardware to its home position
Documented attack patterns abuse exactly the kind of access home_robot gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Opentrons MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for home_robot:
{
"version": "1",
"default": "deny",
"tools": {
"home_robot": {
"limits": [
{
"counter": "home_robot_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}home_robot stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Home robot axes or specific pipette. It is categorised as a Execute tool in the Opentrons MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Opentrons MCP Server MCP server in PolicyLayer and add a rule for home_robot: 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 Opentrons MCP Server. Nothing to install.
home_robot is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the home_robot 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 home_robot. 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.
home_robot is provided by the Opentrons MCP Server MCP server (yerbymatey/opentrons-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Opentrons MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
14 Opentrons MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.