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

Annotations already indicate this is a write operation (readOnlyHint=false, destructiveHint=false). The description adds meaningful behavioral context: waitSync controls whether the response includes links, timezone is stored as-is rather than replaced by the user timezone, and all-day events use YYYY-MM-DD. These are non-obvious behaviors that help an agent predict side effects.

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 core purpose appears in the first sentence, followed by the most important constraints. It covers 12 parameters without becoming a wall of text, though a couple of details (e.g., status enum values) are also present in the schema and could be trimmed.

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 create tool with 12 parameters and an output schema, the description covers the essential decision points: required field, date/time formats, timezone semantics, recurrence, status, type, and waitSync behavior. It does not explain return values, but the output schema exists, so that is not a gap. It could be more explicit about when to omit calendarId, but the schema already says 'omit for the default calendar'.

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 description coverage is 100%, so the schema already documents every parameter. The description adds value by clarifying the timezone behavior, the waitSync trade-off, and the all-day date format, which are semantic details beyond the schema's field-level 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 states a specific verb ('Create') and resource ('event or task'), and immediately distinguishes the two item types. It also names the required field and key constraints, so an agent can tell this tool from siblings like update_event or set_event_status without opening the schema.

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 clear context for when to use the tool: creating an event or task for the authenticated user, with the required title and optional scheduling fields. It does not explicitly name alternatives or exclusions, but the sibling list and the create/update distinction make the usage context reasonably clear.

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