AI agents invoke gns3_stop_node to trigger actions in GNS3 Network Simulator 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.
This tool executes a command that changes the state of a network simulation node by stopping it. While not destructive (the node can be restarted), it is an Execute action because it triggers an external operation with effects determined by the arguments provided.
From the tool's definition Tool name is 'gns3_stop_node' with description 'Stop a specific node.' This performs an operational action (stopping a running simulation node) whose effects depend on which node is targeted.
Documented attack patterns abuse exactly the kind of access gns3_stop_node gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and GNS3 Network Simulator MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for gns3_stop_node:
{
"version": "1",
"default": "deny",
"tools": {
"gns3_stop_node": {
"limits": [
{
"counter": "gns3_stop_node_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}gns3_stop_node 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 specific node. It is categorised as a Execute tool in the GNS3 Network Simulator MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the GNS3 Network Simulator MCP Server MCP server in PolicyLayer and add a rule for gns3_stop_node: 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 GNS3 Network Simulator MCP Server. Nothing to install.
gns3_stop_node 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 gns3_stop_node 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 gns3_stop_node. 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.
gns3_stop_node is provided by the GNS3 Network Simulator MCP Server MCP server (wael-rd/gns3-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from GNS3 Network Simulator 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.
42 GNS3 Network Simulator MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.