List all calendars accessible to the authenticated user
AI agents call list_calendars to retrieve information from VaultAssist without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only queries and returns calendar data without altering state. It is a straightforward read operation that retrieves information the authenticated user already has access to. The blast radius of misuse is minimal—unauthorized enumeration of calendars is a low-severity information disclosure risk.
From the tool's definition Tool name is 'list_calendars' and description states 'List all calendars accessible to the authenticated user' — a pure retrieval operation with no modification, deletion, or side effects.
Documented attack patterns abuse exactly the kind of access list_calendars gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and VaultAssist, and nothing reaches the server without passing your rules. This is the rule we recommend for list_calendars:
{
"version": "1",
"default": "deny",
"tools": {
"list_calendars": {}
}
}list_calendars is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all calendars accessible to the authenticated user. It is categorised as a Read tool in the VaultAssist MCP Server, which means it retrieves data without modifying state.
Register the VaultAssist MCP server in PolicyLayer and add a rule for list_calendars: 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 VaultAssist. Nothing to install.
list_calendars 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_calendars 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_calendars. 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_calendars is provided by the VaultAssist MCP server (3xcaffeine/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from VaultAssist, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
79 VaultAssist tools catalogued and risk-classified — across an index of 43,000+ MCP servers.