Create a Gmail filter for automatic message processing.
AI agents use createGmailFilter to create or update resources in Google Workspace MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Google Workspace MCP Server environment.
Creating a Gmail filter is a write operation that adds or modifies email processing rules. While filters affect how emails are handled, they are configuration changes that can be edited or deleted without irreversible data loss. This is more severe than a simple read operation but less severe than destructive actions (which would permanently delete emails) or financial operations.
From the tool's definition Tool name 'createGmailFilter' and description 'Create a Gmail filter for automatic message processing' indicate creation of a new filter configuration. This is a write operation that modifies Gmail settings reversibly.
Documented attack patterns abuse exactly the kind of access createGmailFilter gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Google Workspace MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for createGmailFilter:
{
"version": "1",
"default": "deny",
"tools": {
"createGmailFilter": {
"limits": [
{
"counter": "creategmailfilter_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}createGmailFilter stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Create a Gmail filter for automatic message processing. It is categorised as a Write tool in the Google Workspace MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Google Workspace MCP Server MCP server in PolicyLayer and add a rule for createGmailFilter: 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 Google Workspace MCP Server. Nothing to install.
createGmailFilter is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the createGmailFilter 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 createGmailFilter. 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.
createGmailFilter is provided by the Google Workspace MCP Server MCP server (sputnicyoji/google-workspace-mcp-with-script). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Google Workspace MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
72 Google Workspace MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.