Microsoft 365 MCP Server

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

Annotations explicitly mark this as destructive (destructiveHint: true, readOnlyHint: false), so the description does not need to establish the mutation nature. However, it adds no context about partial update behavior, idempotency, what happens if the event is not found, or required permissions beyond the 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?

The description mixes technical implementation detail ('navigation property') with a seemingly unrelated security tip about email addresses. The structure is disjointed—one cryptic sentence followed by an emoji-led warning—rather than a coherent explanation front-loaded with purpose.

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?

For a complex mutation operation with deeply nested event properties (body, attendees, attachments) and no output schema, the description is insufficient. It fails to mention required identifiers (calendarId, eventId) in the text, explain what constitutes a successful update, or describe validation constraints beyond the raw schema.

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 high at 80%, with detailed descriptions for the complex nested body object (attendees, start/end times, etc.) and path parameters. The description text contributes nothing about parameters, but the high schema coverage meets the baseline without requiring compensatory description text.

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 uses obscure Graph API technical jargon ('navigation property events in me') rather than clear user-facing language. While 'Update' and 'events' are present, the phrase 'navigation property' and 'in me' (referring to the /me endpoint) create confusion without clarifying what distinguishes this tool from the sibling update-calendar-event.

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?

Contains one specific operational tip about not guessing email addresses and using list-users instead, which is relevant when updating attendees. However, lacks general guidance on when to use this tool versus update-calendar-event or other calendar operations, and does not explain the workflow for identifying calendarId and eventId.

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