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

The description discloses important behavioral traits: adding guests emails each an invitation from the user's address, no guests notifies nobody, and addVideoMeeting attaches a Teams link without recording/transcribing. These go beyond the schema and annotations (which are absent), providing valuable context about side effects. It doesn't mention permissions or reversibility, but the key side effects are covered.

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?

Three sentences with zero waste. The most important behavioral facts (invitation side effects, Teams link behavior) are front-loaded. Every sentence earns its place.

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 10-parameter tool with no output schema, the description covers the critical behavioral aspects: guest invitations, all-day event semantics, timezone handling, and Teams link behavior. It doesn't explain return values, but the absence of an output schema lowers the bar. The description is complete enough for an agent to call the tool correctly without opening the 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 coverage is 60%, and the description adds meaning to key parameters: attendees (emails invitations), addVideoMeeting (Teams link behavior), and the all-day event semantics for start/end. The timeZone parameter is well-documented in the schema, and the description reinforces the importance of setting it. The description compensates for the 40% gap by explaining the behavioral implications of parameters.

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 states a clear verb and resource: 'Create an event' in Outlook Calendar. It distinguishes itself from siblings like create_google_calendar_event and update_outlook_calendar_event by the resource and action, though it doesn't explicitly name a sibling. The title and description align well.

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 context on when to use this tool: creating an Outlook calendar event. It doesn't explicitly state when not to use it or name alternatives, but the sibling list makes the distinction obvious. The note about confirming with the user before inviting guests is a useful usage guideline.

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