email_flag

THE RISK

Critical Risk

Why email_flag needs a policy

The tool is explicitly labeled 'DESTRUCTIVE' in its description, suggesting irreversible or significant side effects. The dry-run default with a confirm=true gate reinforces that applying the action has meaningful consequences.

From the tool's definition DESTRUCTIVE. Defaults to dry-run; pass confirm=true to apply.

Documented attack patterns abuse exactly the kind of access email_flag gives an agent:

POLICY

How to control email_flag

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Email Service, and nothing reaches the server without passing your rules. This is the rule we recommend for email_flag:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "email_flag"
  ]
}

email_flag disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register MCP Email Service — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MCP Email Service tools

Destructive email_delete DESTRUCTIVE. Defaults to dry-run; pass confirm=true to delete. By default moves to Trash; Destructive cleanup Rule-based classifier into protected_finance/protected_travel/security/support_case (never Destructive email_move DESTRUCTIVE. Defaults to dry-run; pass confirm=true to apply. Execute digest_run DESTRUCTIVE if confirm=true (sends notifications to Lark/Telegram). Defaults to dry-run pr Write email_send DESTRUCTIVE / IRREVERSIBLE. Defaults to dry-run preview; pass confirm=true to actually sen Write sync_force Refresh the local SQLite cache from IMAP. Synchronous; can take 5-30s for first sync. Subs Write email_mark DESTRUCTIVE. Defaults to dry-run; pass confirm=true to actually flip flags. Read account_list Returns every account known to mailbox: id, email, provider (gmail/qq/163/outlook/...), IM

All 16 MCP Email Service tools →

Destructive tools on other servers

Android Forensics ADB MCP Server create_full_backup 0xarchive web3_revoke_key Frida Game Hacking MCP clear_scan cPanel MCP Server clear_spam_box

Go deeper

Critical-risk tools in MCP Email Service → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about email_flag

What does the email_flag tool do? +

DESTRUCTIVE. Defaults to dry-run; pass confirm=true to apply. It is categorised as a Destructive tool in the MCP Email Service MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on email_flag? +

Register the MCP Email Service MCP server in PolicyLayer and add a rule for email_flag: 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 Email Service. Nothing to install.

What risk level is email_flag? +

email_flag is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit email_flag? +

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

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

email_flag is provided by the MCP Email Service MCP server (leeguooooo/mailbox). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP Email Service tool call.

Start from MCP Email Service, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →