Microsoft 365 MCP Server

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

The description adds valuable behavioral context beyond the readOnlyHint annotation by explaining that the tool returns 'expanded recurring event instances (not just seriesMaster)' and includes linkage fields like 'seriesMasterId and type.' It also explains the pagination behavior for large result sets. This disclosure of instance expansion behavior is crucial for agents to understand the difference between this and listing raw calendar events.

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 suffers from a poor opening with tautological sentences ('The calendar view for the calendar') that should be removed, but the TIP section is efficiently written with high information density. The emoji and 'TIP' label slightly detract from professional conciseness but the content is valuable. Overall, the structure is inverted with API jargon preceding practical guidance.

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?

Despite lacking an output schema, the description adequately explains return values by noting 'Each instance includes seriesMasterId and type fields' and describing the expanded recurring event format. It covers pagination, timezone handling (via parameter), and extended properties options. For a 16-parameter read operation, it successfully highlights the key functional behaviors agents need to understand.

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 coverage, the baseline documentation is complete, but the description adds practical usage guidance by emphasizing the ISO 8601 format for date parameters and specifically advising when to use fetchAllPages. The reinforcement of the date format requirements adds clarity beyond the schema examples. This compensates for the high parameter count by highlighting the most critical configuration options.

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 TIP section clearly states the tool 'Returns expanded recurring event instances... within a date range for a specific calendar,' providing a specific verb, resource, and scope. However, the opening sentence 'The calendar view for the calendar' is tautological and wastes space. The description successfully distinguishes this from generic calendar views by emphasizing the specific calendar ID requirement and expanded recurring event behavior.

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 prerequisites stating it 'Requires startDateTime and endDateTime query parameters' and offers pagination guidance ('Use fetchAllPages=true... when there are many events'). While it differentiates implicitly by describing 'expanded recurring event instances' (likely distinct from list-specific-calendar-events), it lacks explicit when-to-use guidance comparing against sibling tools like get-calendar-view. The required parameter emphasis helps agents understand prerequisites.

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