update_calendar_event

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

With no annotations, the description must disclose side effects. It states the input and return value but does not mention that updating is destructive (overwrites previous data), any permission requirements, or implications for recurrence. It also omits that partial updates might be allowed (only specified fields are changed). This leaves room for assumptions about mutability and safety.

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 well-structured with a clear summary, bulleted use cases, a parameter list, and return statement. It is appropriately sized for 8 parameters—each parameter gets a brief line but no long prose. Front-loaded with the core purpose, so the key information is immediately visible.

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 tool's complexity (8 optional params) and lack of annotations/output schema, the description covers the basics but misses important context: whether allDay interacts with startsAt/endsAt, any behavioral quirks (e.g., event recurrence), and what happens if a field is omitted (partial update or reset). Not incomplete but leaves gaps that could lead to misuse.

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 schema coverage is 100% with detailed descriptions for each parameter. The tool description repeats parameter names and adds small examples but does not add substantial meaning beyond the schema. However, it clarifies that startsAt/endsAt are ISO format and categoryIds map to family members, which is redundant. Meets baseline for high coverage.

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 updates an existing calendar event, with specific examples (changing time, details, renaming) and distinguishes it from siblings like create_calendar_event and delete_calendar_event. The purpose is unambiguous and well-scoped.

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 provides clear 'Use this when' examples covering common scenarios, which helps the agent decide when to invoke it. It does not explicitly mention when NOT to use it (e.g., creating vs updating), but the context of 'existing event' and sibling names implies the distinction. Slight gap in explicit exclusions, but adequate.

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