Create Calendar

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

Annotations already declare this is a non-destructive write (readOnlyHint=false, destructiveHint=false, openWorldHint=true), and the description adds two pieces of context the annotations cannot convey: the required scope "calendar.write" and the side-effect boundary that no invitations or email reminders are sent. The idempotency behavior is covered by the annotation and the Idempotency-Key schema field, so the remaining gap is minor.

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 short sentences, front-loaded with the action and the usage gate before the auth and side-effect notes. No redundant wording, though the separate "does not send invitations or email reminders" sentence is slightly tangential for a calendar-creation tool.

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?

With annotations covering safety and idempotency, a 100%-covered input schema, and an output schema that removes the need to describe return values, the description supplies exactly the missing pieces: the required permission and the absence of notification side effects. Nothing an agent needs to call this correctly is absent.

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 100%, with name, time_zone, mailbox_id, and Idempotency-Key all documented in the schema itself. The description adds only the adjective "private" for the name parameter and nothing about time_zone format or mailbox_id targeting, so the baseline of 3 is appropriate.

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 and resource ("Create a private calendar") and scopes it as private, which is meaningful against calendar listing/getting siblings. It does not explicitly differentiate itself from mailbox_create_calendar_event, which is the closest sibling, so an agent must infer the calendar-vs-event distinction from names alone.

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 phrase "only when the user asks" gives a clear gating condition for invoking the tool, but there is no mention of alternatives (e.g., use create_calendar_event to add events, list_calendars to check existing ones) and no explicit when-not guidance beyond the user-request constraint.

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