AI agents use update_language 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 creates or modifies configuration data (language preference) reversibly. It is not a Read operation (does not retrieve data), Execute (does not run code or trigger external workflows), Destructive (settings can be changed back), or Financial (no monetary implications). The low severity reflects that misconfiguring language settings has minimal blast radius — the user can easily correct it.
From the tool's definition Tool name is 'update_language' and description states 'Updates language settings' — this modifies user preferences/settings in Gmail without deleting or executing external operations.
Documented attack patterns abuse exactly the kind of access update_language 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_language:
{
"version": "1",
"default": "deny",
"tools": {
"update_language": {
"limits": [
{
"counter": "update_language_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_language 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 language 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_language: 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_language 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_language 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_language. 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_language 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.