calendar_update_event

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

The annotations already flag this as destructive and not read-only, so the description does not need to restate that. It adds meaningful behavioral context: only provided fields are changed, preventing the agent from assuming null values clear fields. It also states the return shape, which is useful behavior beyond 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?

The description is compact and front-loaded. The first sentence states the operation, the second clarifies the update semantics, and the returns line is brief and useful. There is no redundancy or filler.

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?

Given the schema's detailed parameter descriptions and the annotations covering read-only/destructive behavior, the description is largely complete. It covers the key partial-update rule and return format. Minor gaps like error handling or permission requirements exist, but they are not critical for an agent to invoke the tool 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?

The description does not enumerate individual parameters, but the schema already provides strong per-field descriptions like 'New start time (RFC3339 or YYYY-MM-DD), if changing it.' The description's 'Only provided fields change' adds a useful cross-cutting rule, but it does not carry the parameter-documentation burden.

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 clearly states a specific operation ('Update fields') on a specific resource ('existing calendar event'). The phrase 'Only provided fields change' adds partial-update semantics and helps differentiate this from create_event and delete_event siblings.

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 description implies when to use it: when modifying an existing calendar event rather than creating or deleting one. However, it does not explicitly name alternatives or state when not to use this tool, leaving the agent to infer routing from the tool name and sibling list.

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