Alice · Mcp Registry Registry MCP: Risk & Policy

WHAT IT DOES

What Alice does on Mcp Registry Registry

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

WHY IT NEEDS A POLICY

Why Alice needs a policy

Sending an email modifies external state (adds a message to a recipient's inbox) but is reversible (can be unsent or deleted in most systems). This is a write operation. Severity is medium because an AI agent misusing this could spam, phish, or send fraudulent emails to many recipients, but it lacks the irreversibility of destructive actions or the financial impact of payment tools.

From the tool's definition Tool description states 'Send an email' — this creates and transmits a message, a reversible write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

Alice Rate-limited

Alice 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": {
    "Alice": {
      "limits": [
        {
          "counter": "alice_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 Registry Registry, so you can run agents against it safely.

FAQ

Questions about Alice

What does the Alice tool do? +

Send an email. It is categorised as a Write tool in the Mcp Registry Registry MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on Alice? +

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

What risk level is Alice? +

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

Can I rate-limit Alice? +

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

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

Alice is provided by the Mcp Registry Registry MCP server (@mastra/mcp-registry-registry). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.