Mark all emails as read.
AI agents use mark_emails_as_read to create or update resources in Gmail — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Gmail environment.
This tool changes the read status of emails, which is a modification operation. However, it is fully reversible (emails can be marked unread again, as evidenced by the sibling tool 'mark_emails_as_unread'), has limited blast radius, and does not delete, destroy, or move money. Therefore, it is classified as Write with low severity.
From the tool's definition Tool name 'mark_emails_as_read' and description 'Mark all emails as read' indicates modification of email metadata (read status), which is reversible.
Documented attack patterns abuse exactly the kind of access mark_emails_as_read gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Gmail, and nothing reaches the server without passing your rules. This is the rule we recommend for mark_emails_as_read:
{
"version": "1",
"default": "deny",
"tools": {
"mark_emails_as_read": {
"limits": [
{
"counter": "mark_emails_as_read_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}mark_emails_as_read 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.
Mark all emails as read. It is categorised as a Write tool in the Gmail MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Gmail MCP server in PolicyLayer and add a rule for mark_emails_as_read: 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. Nothing to install.
mark_emails_as_read 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 mark_emails_as_read 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 mark_emails_as_read. 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.
mark_emails_as_read is provided by the Gmail MCP server (ivanlhz/gmail-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Gmail, 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.
12 Gmail tools catalogued and risk-classified — across an index of 43,000+ MCP servers.