Microsoft 365 MCP Server

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

Beyond the readOnlyHint annotation, the description adds valuable behavioral context: it discloses that 'this operation returns event bodies in only HTML format' (format limitation) and clarifies the distinction between series masters and expanded instances. It attempts to explain cross-user access patterns (relevant to openWorldHint: true) but cuts off mid-sentence.

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 contains relevant information in the first three sentences, but has a significant structural defect: it ends with an incomplete sentence ('There are two scenarios where an app can get events in another user's calendar:'). This truncation suggests missing content and leaves the description technically incomplete.

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 13 parameters with full schema coverage and no output schema, the description adequately covers the core purpose and behavioral constraints (HTML-only, masters vs instances). However, the incomplete final sentence creates a gap regarding delegated access permissions, and there's no mention of pagination behavior despite the presence of pagination parameters (top, skip, fetchAllPages).

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 100% schema description coverage across 13 parameters, the schema definitions carry the full semantic burden. The description does not add parameter-specific guidance (e.g., that 'timezone' accepts IANA names), but at this coverage level, the baseline 3 is appropriate as the schema documentation is complete.

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 'Get a list of event objects in the user's mailbox' with specific verb and resource. It distinguishes its scope by specifying it returns 'single instance meetings and series masters' (not expanded instances), and explicitly contrasts itself with sibling tools by mentioning 'To get expanded event instances, you can get the calendar view' (referencing get-calendar-view) and 'get the instances of an event' (referencing list-calendar-event-instances).

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 clear guidance on when not to use this tool ('To get expanded event instances') and alternatives to use instead ('get the calendar view, or get the instances of an event'). However, it contains an incomplete sentence cut off ('There are two scenarios where an app can get events in another user's calendar:') that would have explained delegated access patterns, slightly reducing the guidance quality.

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