Create or overwrite one calendar event

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

Annotations already indicate destructive and non-read-only behavior. The description adds critical behavioral context: the API does nothing when event type and duration match, even if start time differs; recommends verifying writes by reading back; states idempotency; declares required scope and that it writes data. This goes well beyond annotations.

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 efficiently structured: clear purpose first, then use case, critical caveat, alternative method, verification advice, scope, and write warning. Every sentence provides necessary information without redundancy.

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 write tool with 8 parameters and no output schema, the description thoroughly covers usage, behavioral nuances, parameter interactions, failure modes, and recommended verification. It also references relevant sibling tools explicitly.

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%, baseline 3. The description adds semantic value by explaining that the event type cannot be changed and why duration_minutes matching prevents start_time_minutes updates, and when custom_day_off_type_id is required.

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 the tool performs an idempotent upsert of a single calendar event by type on a given date, overwriting existing or creating new. It distinguishes from siblings by explicitly contrasting with officient_delete_calendar_event + officient_add_calendar_event for start time changes.

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 includes explicit guidance on when to use alternatives: to move an existing event's start time, use delete then add. It also notes the caveat about same duration preventing update, guiding users away from this tool when that condition is problematic.

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