Set the default Gmail account for operations when no email is specified
AI agents use gmail.setDefaultAccount 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.
This is a Write action because it creates or modifies data (account preference configuration) reversibly. While it has no destructive impact, it meaningfully alters the state of the system for future operations.
From the tool's definition The tool modifies configuration state by setting a default account preference, which is a persistent change to operational settings.
Attacks that exploit this kind of access
Set the default Gmail account for operations when no email is specified. 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 gmail.setDefaultAccount: 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.
gmail.setDefaultAccount 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 gmail.setDefaultAccount 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 gmail.setDefaultAccount. 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.
gmail.setDefaultAccount is provided by the Gmail MCP Server MCP server (shcallaway/gmail-mcp-server). 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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