Microsoft 365 MCP Server

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

Annotations indicate destructiveHint=true and readOnlyHint=false, which the description does not contradict. The description adds value by warning against guessing email addresses, which is a critical behavioral constraint not covered by annotations. However, it misses other behavioral aspects like permission requirements, rate limits, or mutation effects beyond the email tip.

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 is concise with two sentences: one stating the purpose and one providing a critical tip. It is front-loaded with the core function. However, the first sentence is tautological and could be more informative, slightly reducing efficiency.

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 the tool's complexity (4 parameters, nested objects, no output schema) and annotations covering safety (destructive), the description is incomplete. It lacks details on return values, error handling, or scope of updates. The email tip addresses one aspect but does not compensate for broader gaps in a mutation tool with rich input 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 75%, providing good documentation for parameters. The description adds no parameter-specific information beyond the tip about email addresses for attendees, which relates to the 'body.attendees' parameter. This minimal addition does not significantly enhance understanding, aligning with the baseline for high schema coverage.

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 'Update the properties of the event object' is a tautology that restates the tool name ('update-calendar-event') without adding specificity. It does not clarify what 'properties' means or distinguish this tool from sibling tools like 'update-specific-calendar-event'. The tip about email addresses is helpful but does not define the core purpose.

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 provides implicit guidance to use 'list-users' for finding email addresses, suggesting an alternative tool for a related task. However, it lacks explicit when-to-use guidance compared to siblings (e.g., 'update-specific-calendar-event'), prerequisites, or exclusions. The guidance is limited to a specific parameter concern rather than overall usage context.

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