register_agent · Mcp Switchboard MCP: Risk & Policy

WHAT IT DOES

What register_agent does on Mcp Switchboard

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

WHY IT NEEDS A POLICY

Why register_agent needs a policy

This tool creates or updates agent metadata/state in the inter-agent communication system. While idempotent (reversible via deregistration or refresh), it modifies the system's awareness of active agents and their presence on the bus. This is a Write operation rather than Read (which would only query agent status) or Execute (which would trigger external code).

From the tool's definition Tool description states 'Register/refresh this agent on the bus (idempotent)' which creates or modifies agent registration state on the centralized switchboard.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

register_agent Rate-limited

register_agent 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": {
    "register_agent": {
      "limits": [
        {
          "counter": "register_agent_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 Mcp Switchboard, so you can run agents against it safely.

FAQ

Questions about register_agent

What does the register_agent tool do? +

Register/refresh this agent on the bus (idempotent). Call on startup. It is categorised as a Write tool in the Mcp Switchboard MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on register_agent? +

Register the Mcp Switchboard MCP server in PolicyLayer and add a rule for register_agent: 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 Mcp Switchboard. Nothing to install.

What risk level is register_agent? +

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

Can I rate-limit register_agent? +

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

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

register_agent is provided by the Mcp Switchboard MCP server (jemplayer82/mcp-switchboard). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.