List available calendars
AI agents call outlook_list_calendars to retrieve information from Outlook without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves calendar information from Outlook via Microsoft Graph API. It performs no side effects, creates no data, executes no commands, and deletes nothing. Listing available calendars is a straightforward data retrieval operation with minimal security risk—the user can already see their own calendars in Outlook.
From the tool's definition Tool name is 'outlook_list_calendars' and description is 'List available calendars'. The verb 'list' indicates a read-only query operation that retrieves calendar metadata without modification, deletion, or execution of external operations.
Documented attack patterns abuse exactly the kind of access outlook_list_calendars gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Outlook, and nothing reaches the server without passing your rules. This is the rule we recommend for outlook_list_calendars:
{
"version": "1",
"default": "deny",
"tools": {
"outlook_list_calendars": {}
}
}outlook_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 available calendars. It is categorised as a Read tool in the Outlook MCP Server, which means it retrieves data without modifying state.
Register the Outlook MCP server in PolicyLayer and add a rule for outlook_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 Outlook. Nothing to install.
outlook_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 outlook_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 outlook_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.
outlook_list_calendars is provided by the Outlook MCP server (xenoxilus/outlook-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Outlook, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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43 Outlook tools catalogued and risk-classified — across an index of 43,000+ MCP servers.