Stop a running skill for ONE companion (kills the background process).
AI agents invoke companion_stop to trigger actions in Factorio AI Companion. 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.
The tool terminates a background process, which is an external operation execution. While not destructive in the sense of permanent data loss, killing processes can cause game state disruptions, interrupted tasks, or loss of in-progress work depending on the companion's current activity. This makes it Execute rather than Write (which is reversible) or Destructive (which is permanent data loss).
From the tool's definition Tool description states it 'kills the background process' for a companion. This is a process termination action that executes an external operation (stopping a running skill) whose effects depend on which companion is targeted.
Documented attack patterns abuse exactly the kind of access companion_stop gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Factorio AI Companion, and nothing reaches the server without passing your rules. This is the rule we recommend for companion_stop:
{
"version": "1",
"default": "deny",
"tools": {
"companion_stop": {
"limits": [
{
"counter": "companion_stop_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}companion_stop 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.
Free to start. No card required.
Stop a running skill for ONE companion (kills the background process). It is categorised as a Execute tool in the Factorio AI Companion MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Factorio AI Companion MCP server in PolicyLayer and add a rule for companion_stop: 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 Factorio AI Companion. Nothing to install.
companion_stop 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 companion_stop 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 companion_stop. 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.
companion_stop is provided by the Factorio AI Companion MCP server (lveillard/factorio-ai-companion). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Factorio AI Companion, 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.
3 Factorio AI Companion tools catalogued and risk-classified — across an index of 43,000+ MCP servers.