register · Agent Bus MCP: Risk & Policy

Q: What risk level is register?

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

WHAT IT DOES

What register does on Agent Bus

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

WHY IT NEEDS A POLICY

Why register needs a policy

This tool creates or modifies state (agent registration) rather than reading it or executing arbitrary operations. While registration itself is not destructive, it does persist a session identity to a shared system that other agents can discover and interact with.

From the tool's definition The 'register' tool writes a new session identity to a shared message bus, creating a persistent record of an agent on the local network.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

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": {
    "register": {
      "limits": [
        {
          "counter": "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 Agent Bus, so you can run agents against it safely.

FAQ

Questions about register

What does the register tool do? +

Register this session as an agent on the bus. Pick a stable name like. It is categorised as a Write tool in the Agent Bus 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? +

Register the Agent Bus MCP server in PolicyLayer and add a rule for 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 Agent Bus. Nothing to install.

What risk level is register? +

Can I rate-limit register? +

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

Set action: deny in the PolicyLayer policy for 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 register? +

register is provided by the Agent Bus MCP server (mustaphasteph/agent-bus). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.