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 specifics: it includes modified exceptions but excludes canceled occurrences, and mentions nullable returns. This discloses important domain-specific filtering behavior that annotations cannot express.

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 first paragraph contains API-documentation cruft ('Navigation property. Read-only. Nullable.') that wastes space without helping tool selection. However, the 💡 TIP section is well-structured and front-loaded with practical guidance, partially redeeming the structure.

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 17-parameter tool with complex recurrence logic, the description adequately covers the critical behavioral edge cases (exceptions vs cancellations) and required query parameters. No output schema exists, but the description sufficiently characterizes the return set composition.

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?

Despite 100% schema coverage (baseline 3), the description adds meaningful context by specifying ISO 8601 date format requirements and providing concrete examples (e.g., 2024-01-01T00:00:00Z), which helps the agent understand the temporal query constraints better than the schema alone.

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 begins with 'The occurrences of a recurring series...' which ambiguously describes an API property rather than stating the tool's action, but the TIP section clarifies with 'Expand a recurring event into individual instances.' It distinguishes from siblings like get-calendar-event by focusing on recurrence expansion, though the opening syntax is confusing.

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 TIP explicitly states when to use this tool: 'Expand a recurring event into individual instances within a date range' and identifies required parameters (startDateTime, endDateTime) with format specification (ISO 8601). Clear prerequisite guidance for targeting recurring series masters.

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