Microsoft 365 MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows this is a safe read operation. The description adds useful behavioral context: it specifies that event bodies are returned only in HTML format, mentions two scenarios for accessing other users' calendars (though not detailed), and hints at pagination/expansion limitations. It doesn't contradict annotations, but could provide more on rate limits or authentication needs.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is moderately concise but could be more front-loaded. It starts with the core purpose, then adds details on content types, alternatives, and limitations. However, the last sentence is incomplete ('There are two scenarios where an app can get events in another user's calendar:'), which reduces clarity and efficiency, making it less than optimal.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (12 parameters, no output schema) and rich annotations (readOnlyHint, openWorldHint), the description is somewhat complete but has gaps. It covers purpose and some behavioral traits, but lacks details on output format beyond HTML, doesn't explain the incomplete sentence about other users' calendars, and could better integrate with sibling tools for a fuller context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with all 12 parameters well-documented in the input schema (e.g., 'top' for limiting items, 'timezone' for IANA timezone). The description adds no additional parameter semantics beyond what the schema provides, so it meets the baseline for high schema coverage without compensating value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'Get a list of event objects in the user's mailbox.' It specifies the resource (event objects) and scope (user's mailbox), and distinguishes content types (single instance meetings and series masters). However, it doesn't explicitly differentiate from sibling tools like 'list-specific-calendar-events' or 'get-calendar-view' beyond mentioning them in passing.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides some usage context by mentioning alternatives ('To get expanded event instances, you can get the calendar view, or get the instances of an event') and hints at scenarios for accessing other users' calendars. However, it doesn't give explicit guidance on when to use this tool versus its siblings (e.g., 'list-specific-calendar-events'), nor does it outline prerequisites or exclusions clearly.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.