Update a calendar event

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

Annotations provide idempotentHint and destructiveHint. The description adds partial-update behavior ('Only the fields you provide are changed.') and clarifies time format (local wall-clock + IANA time zone), which goes beyond annotations. No contradictions.

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?

Three concise sentences each serving a distinct purpose: purpose, partial update, time format, and usage instruction. No redundancy, front-loaded with the most critical information.

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 8 parameters, nested objects, destructive action, and no output schema, the description covers core functionality, partial update, time handling, and user confirmation. Missing return value description, which would be helpful since no output schema exists.

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 75%, with detailed descriptions for most parameters. The description adds value by summarizing the partial-update nature and time zone handling, complementing the schema without repeating it. Not all params are mentioned, but the schema covers them.

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 verb 'Update' and specifies the resource 'an existing calendar event' and some fields (time, location, subject, body). It distinguishes from list/read tools but does not explicitly differentiate from create_event (e.g., by stating not for creation).

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 usage for modifying existing events and provides a direct instruction to 'Confirm changes with the user before calling.' However, it does not mention when not to use this tool or name alternatives like create_event for new events.

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