Create a new device for a specific firewall
AI agents use create_firewall_device to create or update resources in Linode MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Linode MCP Server environment.
This tool creates a new device association within a firewall rule, which is a reversible write operation. While firewalls are security-critical infrastructure, the tool itself only adds a device to an existing firewall (does not delete, does not execute code, and does not move money).
From the tool's definition Tool name is 'create_firewall_device' and description states 'Create a new device for a specific firewall'. The verb 'create' indicates a write operation that adds a new resource to the firewall configuration.
Documented attack patterns abuse exactly the kind of access create_firewall_device gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Linode MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_firewall_device:
{
"version": "1",
"default": "deny",
"tools": {
"create_firewall_device": {
"limits": [
{
"counter": "create_firewall_device_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_firewall_device stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Create a new device for a specific firewall. It is categorised as a Write tool in the Linode MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Linode MCP Server MCP server in PolicyLayer and add a rule for create_firewall_device: 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 Linode MCP Server. Nothing to install.
create_firewall_device is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the create_firewall_device 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 create_firewall_device. 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.
create_firewall_device is provided by the Linode MCP Server MCP server (takashito/linode-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Linode MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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416 Linode MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.