auth_complete · Mail Cal Drive MCP: Risk & Policy

WHAT IT DOES

What auth_complete does on Mail Cal Drive

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

WHY IT NEEDS A POLICY

Why auth_complete needs a policy

This tool finalizes an authentication handshake, establishing credentials/session state in the system. It creates or modifies auth state (Write), but does not delete data, execute code, or move money. Misuse could allow unauthorized account linking, hence medium severity.

From the tool's definition Complete a pending authentication flow... polls for device code completion... checks if OAuth callback was received

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

auth_complete Rate-limited

auth_complete 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": {
    "auth_complete": {
      "limits": [
        {
          "counter": "auth_complete_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 Mail Cal Drive, so you can run agents against it safely.

FAQ

Questions about auth_complete

What does the auth_complete tool do? +

Complete a pending authentication flow. For Microsoft, polls for device code completion. For Google, checks if OAuth callback was received. It is categorised as a Write tool in the Mail Cal Drive MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on auth_complete? +

Register the Mail Cal Drive MCP server in PolicyLayer and add a rule for auth_complete: 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 Mail Cal Drive. Nothing to install.

What risk level is auth_complete? +

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

Can I rate-limit auth_complete? +

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

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

auth_complete is provided by the Mail Cal Drive MCP server (rumbitopi/mail-cal-drive-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.