calendar_update_event

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

Annotations already declare the full safety profile (non-readOnly, idempotent, non-destructive, openWorld). The description adds the recurring-series scoping behavior and the required 'calendar' permission, which are genuine additions not covered by annotations. It does not describe what happens to unspecified fields or any rate/permission failure behavior.

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?

Two tight sentences with the operation and scope front-loaded, plus a compact permission/version tag. No filler, though the bracketed tag is slightly meta rather than task-oriented.

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?

An output schema exists and annotations cover the safety profile, so the description needn't explain returns. With complete parameter documentation and an explicit permission requirement, an agent has enough to invoke it correctly; only sibling routing is left implicit.

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%, so every one of the 10 parameters is documented in the schema itself (including _idempotencyKey reuse rules and calendarId defaulting). The description adds no parameter-level detail beyond the 'native ID' phrasing, so the baseline 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+resource ('Update one occurrence of an event') and its scope ('by native ID'), which clearly separates it from calendar_create_event and calendar_delete_event. It does not explicitly name those siblings, but the operation is unambiguous.

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 line 'Recurring series are not bulk modified' implies the tool operates on a single occurrence rather than a whole series, which is useful scoping. However, it never states when to choose this over calendar_create_event/calendar_delete_event, and gives no prerequisites or exclusions beyond that hint.

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