AI agents call cal_get_event to retrieve information from M365 without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves calendar event information by ID without creating, modifying, deleting, or executing any operations. It is a read-only query operation with minimal blast radius—even if misused by an AI agent, it only exposes existing calendar data the user has access to via OAuth 2.1 delegation.
From the tool's definition Tool name 'cal_get_event' and description 'Get the full details of a specific calendar event by ID, including the full body/description' indicate retrieval of calendar event metadata and content without modification or side effects.
Attacks that exploit this kind of access
Get the full details of a specific calendar event by ID, including the full body/description. The event_id MUST be from a recent cal_list_events response. It is categorised as a Read tool in the M365 MCP Server, which means it retrieves data without modifying state.
Register the M365 MCP server in PolicyLayer and add a rule for cal_get_event: 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 M365. Nothing to install.
cal_get_event 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 cal_get_event 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 cal_get_event. 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.
cal_get_event is provided by the M365 MCP server (swamirama/m365-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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