AI agents call delete_filter 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.
Deleting a filter is an irreversible action that cannot be undone without manual reconfiguration. While the blast radius is not catastrophic (it doesn't delete emails themselves), it permanently removes a user's filter rule and its associated settings. This fits the Destructive category.
From the tool's definition Tool name is 'delete_filter' with description 'Deletes a filter'. The verb 'Deletes' explicitly indicates irreversible removal of data (an email filter configuration).
Documented attack patterns abuse exactly the kind of access delete_filter 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 delete_filter:
{
"version": "1",
"default": "deny",
"hide": [
"delete_filter"
]
}delete_filter disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
Free to start. No card required.
Deletes a filter. 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 delete_filter: 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.
delete_filter 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 delete_filter 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 delete_filter. 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.
delete_filter 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.