create_inbox · Lobstermail MCP: Risk & Policy

WHAT IT DOES

What create_inbox does on Lobstermail

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

WHY IT NEEDS A POLICY

Why create_inbox needs a policy

Creating an inbox is a reversible write operation (the inbox can be deleted via delete_inbox). It does not execute arbitrary code, delete data irreversibly, or move money. The severity is medium because email inboxes are communication channels; an attacker could create numerous inboxes for spam or impersonation, but the damage is containable and reversible.

From the tool's definition Tool description states 'Create a new email inbox' — this is a creation operation that modifies the account's data structure by adding a new inbox resource.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_inbox Rate-limited

create_inbox 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": {
    "create_inbox": {
      "limits": [
        {
          "counter": "create_inbox_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 Lobstermail, so you can run agents against it safely.

FAQ

Questions about create_inbox

What does the create_inbox tool do? +

Create a new email inbox. Returns an @lobstermail.ai address. It is categorised as a Write tool in the Lobstermail MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_inbox? +

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

What risk level is create_inbox? +

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

Can I rate-limit create_inbox? +

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

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

create_inbox is provided by the Lobstermail MCP server (lobster-kit/mcp-server-lobstermail). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.