mcp_server_register · LocalAnt MCP: Risk & Policy

WHAT IT DOES

What mcp_server_register does on LocalAnt

AI agents use mcp_server_register to create or update resources in LocalAnt — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your LocalAnt environment.

WHY IT NEEDS A POLICY

Why mcp_server_register needs a policy

This tool creates a new registration entry for a downstream MCP server, which is a reversible write operation. However, registering a new server through the gateway could expand the attack surface by adding new tools/capabilities accessible to the AI agent, making it medium severity. It does not execute code directly or irreversibly destroy data.

From the tool's definition Register a downstream MCP server (stdio or streamable-http) to bridge through the gateway.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mcp_server_register Rate-limited

mcp_server_register 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "mcp_server_register": {
      "limits": [
        {
          "counter": "mcp_server_register_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches LocalAnt, so you can run agents against it safely.

FAQ

Questions about mcp_server_register

What does the mcp_server_register tool do? +

Register a downstream MCP server (stdio or streamable-http) to bridge through the gateway. It is categorised as a Write tool in the LocalAnt MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on mcp_server_register? +

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

What risk level is mcp_server_register? +

mcp_server_register is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit mcp_server_register? +

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

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

mcp_server_register is provided by the LocalAnt MCP server (yuga-hashimoto/localant). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.