Send an email via Gmail. Supports threading for replies.
AI agents use sendGmailMessage 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.
Sending email creates new messages and modifies the state of the mailbox/conversation threads, making it a Write operation. Severity is medium because email can be misused for spam, phishing, or harassment, but the impact is typically contained to the message recipients rather than affecting the system at large or causing financial harm. Confidence is high because the tool's purpose is explicit and unambiguous.
From the tool's definition Tool name is 'sendGmailMessage' and description states 'Send an email via Gmail.' This directly performs the action of composing and sending email messages, which creates new data (the email) in Gmail's system.
Documented attack patterns abuse exactly the kind of access sendGmailMessage 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 sendGmailMessage:
{
"version": "1",
"default": "deny",
"tools": {
"sendGmailMessage": {
"limits": [
{
"counter": "sendgmailmessage_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}sendGmailMessage 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.
Free to start. No card required.
Send an email via Gmail. Supports threading for replies. 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 sendGmailMessage: 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.
sendGmailMessage 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 sendGmailMessage 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 sendGmailMessage. 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.
sendGmailMessage 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.