calendar_update_event

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

With no annotations, the description carries the full burden and does disclose meaningful behavior: updates are partial, omitted fields retain existing values, and specific empty-string values clear fields. It also explains that the returned event reflects stored data. It still lacks auth, error, and rate-limit 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?

The description is front-loaded with purpose and uses a clear Args block. The returned-event paragraph is somewhat long but earns its place by explaining omission behavior and avoiding a re-fetch. Overall it is well structured with minor verbosity.

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 14-parameter mutation tool with no annotations and no output schema, the description is not complete enough. It cannot document all parameters, auth requirements, error cases, or return structure, so an agent still lacks important context despite the useful partial-update explanation.

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 0% for 14 parameters, so the description must compensate. It documents event_uid and calendar_name and gives clearing semantics for end_datetime, location, recurrence_rule, and recurring, but defers most other fields to calendar_create_event without describing them, leaving substantial gaps.

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 ('Update an existing event') and immediately clarifies partial-update semantics ('Only the arguments you pass are changed'). It implicitly distinguishes from calendar_create_event by saying 'existing event', though it does not name siblings or address overlap with calendar_upsert_events.

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 useful update behavior and operational details, such as omitting calendar_name to search all calendars and clearing values with empty strings. However, it gives no explicit when-to-use guidance versus alternatives like calendar_create_event or calendar_upsert_events, nor any prerequisites.

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