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

Annotations cover readOnly=false, destructive=true and openWorld=true, so the safety bar is already met, yet the description adds real side-effect context: inviting guests emails them an invitation, the reverse case notifies nobody, and addVideoMeeting creates a link without recording or joining. That is meaningful external-effect disclosure beyond the annotations.

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?

Four tight sentences, front-loaded with the core action, and each sentence carries distinct information (date formats, guest side effect, video flag). No padding or restatement of the name.

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 destructive, open-world mutation with no output schema, the description covers the highest-risk behaviors (outbound invitations, video attachment). It omits where the event lands by default and any recurrence/calendarId guidance, but nothing an agent must know to call it safely is missing.

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 60% schema coverage the description usefully adds the guest-notification consequence and the Meet-link behavior for addVideoMeeting, and clarifies the date-format contract for start/end. It leaves calendarId, location, timeZone and description semantics to the schema, so it compensates but does not fully cover the gap.

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?

States a specific verb+resource ("Create an event") that distinguishes it from the nearest lookalike, create_google_calendar. It does not explicitly differentiate from the parallel create_outlook_calendar_event sibling, but the resource name makes the provider obvious.

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?

Provides conditional guidance on date formats (all-day vs timed) and implies guest behavior, but never states when to prefer this over create_outlook_calendar_event or update_google_calendar_event. Usage is inferable rather than explicit.

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