AI agents call list_labels to retrieve information from Gmail without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves organizational information (labels and folders) from Gmail without side effects. It is a read-only operation that queries existing data structure. The blast radius is minimal since listing labels cannot expose sensitive email content itself and causes no state changes. Severity is low given the limited nature of the information exposed.
From the tool's definition The tool 'list_labels' lists Gmail labels and folders. The server description confirms it 'Enables reading Gmail emails' with operations like 'listing.' The tool performs no modification, deletion, or execution—it only retrieves metadata about label…
Attacks that exploit this kind of access
List all Gmail labels and folders. It is categorised as a Read tool in the Gmail MCP Server, which means it retrieves data without modifying state.
Register the Gmail MCP server in PolicyLayer and add a rule for list_labels: 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.
list_labels is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_labels 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 list_labels. 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.
list_labels is provided by the Gmail MCP server (symbolstar/gmail-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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