AI agents call trash_message to permanently remove resources in Gmail MCP — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Moving a message to trash is a destructive operation that removes it from the inbox. While Gmail trash can theoretically be restored within 30 days, this is an irreversible action from the user's workflow perspective and can lead to data loss if trash is auto-emptied. The blast radius is high as an AI agent could trash important emails at scale.
From the tool's definition Move a message to the trash
Documented attack patterns abuse exactly the kind of access trash_message gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Gmail MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for trash_message:
{
"version": "1",
"default": "deny",
"hide": [
"trash_message"
]
}trash_message disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
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Move a message to the trash. It is categorised as a Destructive tool in the Gmail MCP MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Gmail MCP server in PolicyLayer and add a rule for trash_message: 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 Gmail MCP. Nothing to install.
trash_message is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the trash_message 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.
Set action: deny in the PolicyLayer policy for trash_message. 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.
trash_message is provided by the Gmail MCP server (shinzo-labs/gmail-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 65 Gmail MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
65 Gmail MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.