calendar_update_event

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

No annotations are provided, so the description carries the burden. It discloses that the tool updates fields and that omitted fields keep existing values. However, it does not mention any side effects, authentication requirements, rate limits, or error scenarios. The description is adequate but minimal.

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 the main purpose and then follows a clear, structured list of arguments. Every sentence serves a purpose, and there is no redundant information. It is efficient for an AI agent to parse.

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 that an output schema exists (from context), the description need not explain return values. It covers all parameters and provides necessary operational details (e.g., 'omit to keep existing'). However, it lacks information on what happens if the href is invalid or on error handling, which would make it more complete.

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 input schema has 0% coverage (no descriptions for parameters). The description adds meaning by explaining each parameter: href from list, title as new summary, start/end as ISO strings, etc. This compensates well for the schema's lack of descriptions.

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 'Update fields on an existing CalDAV event,' providing a specific verb and resource. It distinguishes itself from sibling tools like calendar_create_event and calendar_delete_event by focusing on update operations.

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 gives context for the href parameter (from calendar_list_events) and explains that other fields are optional to keep existing values. However, it does not explicitly state when to use this tool versus alternatives like calendar_create_event or calendar_delete_event, and lacks when-not-to-use guidance.

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