fw_defederate

THE RISK

Critical Risk

Why fw_defederate needs a policy

This tool performs two destructive actions: (1) purging cached content, which irreversibly deletes data, and (2) defederating a domain, which severs federation relationships in a way that requires significant effort to reverse. Although the action is queued and requires operator confirmation (reducing immediate blast radius), the underlying operations are fundamentally destructive and irreversible.

From the tool's definition Full defederation: block domain + purge cached content. The verb 'purge' indicates irreversible deletion of cached content, and 'block domain' is a permanent network-level action that cannot be easily undone.

Documented attack patterns abuse exactly the kind of access fw_defederate gives an agent:

POLICY

How to control fw_defederate

PolicyLayer is an MCP gateway — it sits between your AI agents and Crow, and nothing reaches the server without passing your rules. This is the rule we recommend for fw_defederate:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "fw_defederate"
  ]
}

fw_defederate disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register Crow — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

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Go deeper

Critical-risk tools in Crow → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about fw_defederate

What does the fw_defederate tool do? +

Full defederation: block domain + purge cached content. QUEUED — requires operator confirmation in the Nest panel. It is categorised as a Destructive tool in the Crow MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on fw_defederate? +

Register the Crow MCP server in PolicyLayer and add a rule for fw_defederate: 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 Crow. Nothing to install.

What risk level is fw_defederate? +

fw_defederate is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit fw_defederate? +

Yes. Add a rate_limit block to the fw_defederate 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.

How do I block fw_defederate completely? +

Set action: deny in the PolicyLayer policy for fw_defederate. 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.

What MCP server provides fw_defederate? +

fw_defederate is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Crow tool call.

Start from Crow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →