AI agents call list-filters to retrieve information from Enhanced Gmail MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves filter metadata/configuration from Gmail without side effects. It is purely informational—no filters are created, modified, deleted, or executed. The action is a simple enumeration/query of existing filters, which is characteristic of Read operations. The blast radius is minimal as an AI cannot cause harm by merely viewing filter configurations.
From the tool's definition Tool name 'list-filters' and description 'Lists all email filters in the user' indicate a retrieval operation that queries existing filter configuration data without modifying or executing anything.
Documented attack patterns abuse exactly the kind of access list-filters gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Enhanced Gmail MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list-filters:
{
"version": "1",
"default": "deny",
"tools": {
"list-filters": {}
}
}list-filters is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Lists all email filters in the user. It is categorised as a Read tool in the Enhanced Gmail MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Enhanced Gmail MCP Server MCP server in PolicyLayer and add a rule for list-filters: 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 Enhanced Gmail MCP Server. Nothing to install.
list-filters is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list-filters 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 list-filters. 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.
list-filters is provided by the Enhanced Gmail MCP Server MCP server (theposch/gmail-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Enhanced Gmail MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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27 Enhanced Gmail MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.