AI agents call list_folders to retrieve information from Tbird without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves folder metadata (names) from a user's Thunderbird mail account without modifying, deleting, or executing anything. It has no side effects and poses minimal risk if invoked by an AI agent. Classified as Read with low severity.
From the tool's definition Tool is named 'list_folders' and described as 'List mbox folder names for an account'. The verb 'List' and the action of enumerating folder names without modification are characteristic of read operations.
Attacks that exploit this kind of access
List mbox folder names for an account (by email address). It is categorised as a Read tool in the Tbird MCP Server, which means it retrieves data without modifying state.
Register the Tbird MCP server in PolicyLayer and add a rule for list_folders: 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 Tbird. Nothing to install.
list_folders 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_folders 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_folders. 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_folders is provided by the Tbird MCP server (neil-zielsdorf/tbird-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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