Apply a label to an email
AI agents use label_email to create or update resources in Gmail MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Gmail MCP Server environment.
Labeling constitutes a write operation as it modifies email state by adding organizational metadata. It is reversible (labels can be removed), so it does not qualify as Destructive. The severity is medium because misuse could result in emails being mislabeled (affecting message retrieval and organization), but does not involve deletion, data loss, or financial impact.
From the tool's definition Tool description states 'Apply a label to an email' — labeling is a reversible modification operation that changes email metadata/organization without altering the email content itself.
Attacks that exploit this kind of access
Apply a label to an email. It is categorised as a Write tool in the Gmail MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Gmail MCP Server MCP server in PolicyLayer and add a rule for label_email: 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 Server. Nothing to install.
label_email 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 label_email 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 label_email. 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.
label_email is provided by the Gmail MCP Server MCP server (xiangwanggithub/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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