Microsoft 365 MCP Server

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

Annotations indicate destructive/write behavior, which the description confirms. It adds valuable context not in annotations: the scope (user vs group calendars) and the critical prerequisite about email resolution workflow. It does not contradict annotations.

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?

Two sentences plus a clearly demarcated tip. No wasted words. Front-loaded with the core action. The emoji and 'CRITICAL' label effectively highlight the important prerequisite. Could be improved by removing 'Use this API to' boilerplate.

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?

Covers the essential action and a critical prerequisite (email lookup), but given the complex nested body parameter (4 params, deep nesting) and lack of output schema, it lacks guidance on typical usage patterns, required sub-fields in the body, or what constitutes a successful creation.

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?

With 75% schema coverage, the baseline is 3. The description implies usage of calendarId through the calendar type explanation, and the tip hints at the attendees parameter structure, but offers no additional semantic clarity for the complex nested body object which has dozens of properties.

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 creates a new event in user or Microsoft 365 group calendars, but fails to distinguish from sibling tool 'create-calendar-event' (likely the default calendar variant). Without explicit comparison, agents cannot confidently select between the two creation tools.

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?

Provides excellent specific guidance via the CRITICAL tip to use 'list-users' rather than guessing email addresses, which is a clear prerequisite. However, it lacks guidance on when to use this tool versus the sibling 'create-calendar-event' or other alternatives.

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