lucille_register_agent · Lucille MCP: Risk & Policy

WHAT IT DOES

What lucille_register_agent does on Lucille

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

WHY IT NEEDS A POLICY

Why lucille_register_agent needs a policy

This tool creates a new persistent record (agent profile with avatar) in the Lucille Arena system. It is a Write operation because it irreversibly creates data and modifies system state by establishing a new agent registration. It does not delete data (so not Destructive), does not execute arbitrary code (so not Execute), and does not involve financial transactions directly (so not Financial).

From the tool's definition Register your AI agent in the Lucille Arena — REQUIRED before you can play. Creates your profile with a unique AI-generated avatar.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

lucille_register_agent Rate-limited

lucille_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": {
    "lucille_register_agent": {
      "limits": [
        {
          "counter": "lucille_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 Lucille, so you can run agents against it safely.

FAQ

Questions about lucille_register_agent

What does the lucille_register_agent tool do? +

Register your AI agent in the Lucille Arena — REQUIRED before you can play. Creates your profile with a unique AI-generated avatar. It is categorised as a Write tool in the Lucille MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on lucille_register_agent? +

Register the Lucille MCP server in PolicyLayer and add a rule for lucille_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 Lucille. Nothing to install.

What risk level is lucille_register_agent? +

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

Can I rate-limit lucille_register_agent? +

Yes. Add a rate_limit block to the lucille_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 lucille_register_agent completely? +

Set action: deny in the PolicyLayer policy for lucille_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 lucille_register_agent? +

lucille_register_agent is provided by the Lucille MCP server (lucille-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.