Add a federation-aware reverse-proxy site block. Emits directives for the chosen profile (matrix | activitypub | peertube | generic-ws) — websocket upgrade, large request body, proxy timeouts — plus optional /.well-known/ handlers. Idempotent: re-running with the same domain replaces the existing...
AI agents use caddy_add_federation_site to create or update resources in Crow — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Crow environment.
This is a Write operation: it creates or modifies Caddy site configuration persistently. Although not irreversible (hence not Destructive), it's high-severity because misconfiguration by an AI agent could redirect traffic incorrectly, expose services, or create security vulnerabilities in federation setups. The idempotent nature and potential impact on system routing justify high severity.
From the tool's definition Tool adds/modifies site configuration blocks in Caddy (reverse proxy), with explicit description "replaces the existing block" showing it creates or modifies configuration persistently.
Documented attack patterns abuse exactly the kind of access caddy_add_federation_site gives an agent:
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 caddy_add_federation_site:
{
"version": "1",
"default": "deny",
"tools": {
"caddy_add_federation_site": {
"limits": [
{
"counter": "caddy_add_federation_site_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}caddy_add_federation_site 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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Add a federation-aware reverse-proxy site block. Emits directives for the chosen profile (matrix | activitypub | peertube | generic-ws) — websocket upgrade, large request body, proxy timeouts — plus optional /.well-known/ handlers. Idempotent: re-running with the same domain replaces the existing block. It is categorised as a Write tool in the Crow MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Crow MCP server in PolicyLayer and add a rule for caddy_add_federation_site: 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.
caddy_add_federation_site 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 caddy_add_federation_site 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 caddy_add_federation_site. 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.
caddy_add_federation_site 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.
Start from Crow, 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.
576 Crow tools catalogued and risk-classified — across an index of 43,000+ MCP servers.