create_inbox · AgentMail MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_inbox does on AgentMail MCP Server

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

WHY IT NEEDS A POLICY

Why create_inbox needs a policy

The tool creates a new resource (email inbox) with side effects, but the creation is reversible (the inbox can be deleted). It does not execute arbitrary code, destroy data, move money, or perform read-only operations. This is a straightforward Write action.

From the tool's definition Tool description states 'Create a new email inbox' — a create operation that establishes new persistent state in the email system.

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"
        }
      ]
    }
  }
}

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Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches AgentMail MCP Server, 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. It is categorised as a Write tool in the AgentMail MCP Server 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 AgentMail MCP Server 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 AgentMail MCP Server. 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 AgentMail MCP Server MCP server (kamath/agentmail-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.