AI agents use update_imap to create or update resources in Gmail MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Gmail MCP environment.
This tool modifies email client configuration (IMAP settings) rather than email content or financial transactions. It falls into the Write category because it creates or modifies data reversibly. Severity is medium because misconfiguration could disrupt email access or expose credentials if security settings are weakened, but the changes are not irreversible and do not directly delete data or move money.
From the tool's definition Tool name is 'update_imap' with description 'Updates IMAP settings'. IMAP settings are configuration data that can be modified but typically cannot be irreversibly deleted or cause financial harm.
Documented attack patterns abuse exactly the kind of access update_imap 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 update_imap:
{
"version": "1",
"default": "deny",
"tools": {
"update_imap": {
"limits": [
{
"counter": "update_imap_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_imap 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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Updates IMAP settings. It is categorised as a Write tool in the Gmail MCP 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 update_imap: 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.
update_imap 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 update_imap 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 update_imap. 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.
update_imap 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.
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65 Gmail MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.