List all mailboxes associated with the API key, including plan and usage information.
AI agents call list_mailboxes to retrieve information from agentsbase — Email for AI Agents without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns information about existing mailboxes without modifying, deleting, or executing any operations. It is a pure read operation that gathers metadata about resources. While exposure of mailbox metadata could inform further attacks, the tool itself performs no state-changing actions, making it Read category with low severity.
From the tool's definition Tool name 'list_mailboxes' and description 'List all mailboxes associated with the API key, including plan and usage information' indicate a retrieval operation with no side effects.
Attacks that exploit this kind of access
List all mailboxes associated with the API key, including plan and usage information. It is categorised as a Read tool in the agentsbase — Email for AI Agents MCP Server, which means it retrieves data without modifying state.
Register the agentsbase — Email for AI Agents MCP server in PolicyLayer and add a rule for list_mailboxes: 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 agentsbase — Email for AI Agents. Nothing to install.
list_mailboxes 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_mailboxes 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_mailboxes. 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_mailboxes is provided by the agentsbase — Email for AI Agents MCP server (agentsbase-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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