Update event

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

Beyond the annotations (destructiveHint=true, idempotentHint=false), it discloses that omitted fields stay unchanged, that a new start preserves old duration unless duration_minutes is given, that a recurring event's whole series changes, and that members see changes immediately. That is rich, non-obvious behavioral context an agent could not infer from the schema.

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?

It is front-loaded with purpose and then behavior, and every sentence carries useful information. The only waste is the redundant repetition of 'Admins only' in both paragraphs.

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 12 parameters, full schema coverage, no output schema and annotations covering safety, the description supplies the remaining essentials — partial-update behavior, recurring-series scope, duration defaults and the admin requirement — so an agent has what it needs to call it correctly.

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 100%, so the schema already documents each parameter and the baseline would be 3. The description adds cross-parameter meaning the schema cannot express — the start/duration interaction and the partial-update semantics — pushing it above baseline.

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 opens with a specific verb and resource — 'Change a calendar event's title, time, place or access' — and frames it as editing one existing event, which clearly separates it from create_event, delete_event, get_event and list_events in the sibling set.

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?

It gives concrete usage context: 'Admins only' (stated twice) and 'Edits one event, as the event's Edit does,' which tells the agent this is a partial-update operation. It doesn't explicitly name a when-not condition or point to an alternative tool, so it falls short of a 5.

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