unblock_sender

Remove a sender from the blocked list. Requires TREKMAIL_ALLOW_DESTRUCTIVE=true.

SERVERTrekMail MCP Server SOURCEtrekmail/mcp-server

Critical RISK CLASS

Category Destructive

Parameters 00 required

Recommended Hiddensee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/trekmail-mcp-server/unblock-sender.md

WHAT IT DOES

What unblock_sender does on TrekMail MCP Server

AI agents call unblock_sender to permanently remove resources in TrekMail MCP Server, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.

RISK

Why unblock_sender is rated Critical

While unblocking a sender is not data deletion, it irreversibly removes a security control (the block) and is explicitly gated behind a DESTRUCTIVE flag by the server itself. This indicates the authors consider it a destructive operation. Misuse could expose users to previously blocked malicious senders, giving it medium severity.

From the tool's definition 'Remove a sender from the blocked list' and 'Requires TREKMAIL_ALLOW_DESTRUCTIVE=true'

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs unblock_sender safely

PolicyLayer is an MCP gateway: it sits between your AI agents and TrekMail MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For unblock_sender, this is the rule to start with:

unblock_sender Hidden

unblock_sender is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.

View as policy code

policy.json

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

RESTRICT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect TrekMail MCP Server, apply this rule, and every unblock_sender call is checked against it from then on.

FAQ

Questions about unblock_sender

What does the unblock_sender tool do? +

Remove a sender from the blocked list. Requires TREKMAIL_ALLOW_DESTRUCTIVE=true. It is categorised as a Destructive tool in the TrekMail MCP Server 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 unblock_sender? +

Register the TrekMail MCP Server MCP server in PolicyLayer and add a rule for unblock_sender: 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 TrekMail MCP Server. Nothing to install.

What risk level is unblock_sender? +

unblock_sender 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 unblock_sender? +

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

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

unblock_sender is provided by the TrekMail MCP Server MCP server (trekmail/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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