caddy_list_servers

THE RISK

Low Risk

Why caddy_list_servers needs a policy

This tool queries and returns information about existing server configurations without altering, deleting, or executing operations. It is purely informational, making it a Read operation. Severity is low because discovering server names and listening addresses poses minimal direct security risk, though the information could inform further attacks.

From the tool's definition Tool description explicitly states 'List all configured HTTP servers' with retrieval of names, addresses, route counts, and TLS status—a pure query/discovery operation with no modifications, deletions, or side effects.

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

POLICY

How to control caddy_list_servers

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "caddy_list_servers": {}
  }
}

caddy_list_servers is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

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

CAP THIS TOOL →

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EXPLORE

Related tools and policies

More Caddy tools

Destructive caddy_config_delete Delete config at a JSON path. Removes the config node at the specified path. Deleting a pa Destructive caddy_remove_route Remove a route. Target by @id (preferred — stable across reorderings) or by array index on Destructive caddy_load Replace the entire Caddy configuration atomically. Accepts a JSON config object, or a Cadd Execute caddy_stop Gracefully shut down the Caddy server. Requires confirm=true to prevent accidental shutdow Write caddy_add_route Add a route with full control over match conditions and handlers. Supports any Caddy handl Write caddy_config_set Write config at a JSON path. Mode Write caddy_reverse_proxy Add a reverse proxy route. The most common operation — just specify where traffic comes fr Write caddy_revert Manage config snapshots for rollback. Snapshots are auto-captured before caddy_load and ke

All 18 Caddy tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about caddy_list_servers

What does the caddy_list_servers tool do? +

List all configured HTTP servers with their names, listen addresses, route counts, and TLS status. Use this to discover server names before calling route tools. It is categorised as a Read tool in the Caddy MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on caddy_list_servers? +

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

What risk level is caddy_list_servers? +

caddy_list_servers is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit caddy_list_servers? +

Yes. Add a rate_limit block to the caddy_list_servers 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 caddy_list_servers completely? +

Set action: deny in the PolicyLayer policy for caddy_list_servers. 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 caddy_list_servers? +

caddy_list_servers is provided by the Caddy MCP server (yawlabs/caddy-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Caddy tool call.

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

CHECK YOUR STACK →