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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering safety. The description adds behavioral context beyond annotations by explaining that the output contains calendar.id and that display names must not be used as calendar_id—a common pitfall. No contradiction with 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?

Two sentences with no waste: the first states the purpose, the second delivers a crucial usage constraint. The key information is front-loaded, making it easy to parse quickly.

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?

The description covers the core purpose and a key pitfall, but lacks guidance on pagination (limit, cursor, offset) and does not explain how to handle multiple accounts beyond what the account_id parameter description already provides. Given the low schema coverage and absence of output schema, more detail on these aspects would improve completeness.

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 only 25% (only account_id has a description). The description does not elaborate on limit, cursor, or offset, leaving pagination semantics unexplained. With such low coverage, the description should compensate, but it does not, so agents may misuse these parameters.

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 ('List'), a resource ('calendars'), and the scope ('for the connected Google or Microsoft account'). It also provides a critical usage hint about using calendar.id instead of display names, which clearly differentiates this from other calendar tools like calendar_get_calendar or calendar_create_event.

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 implicitly guides usage by stating to use the returned calendar.id before listing, creating, or updating events, and warns against using display names. It does not explicitly name alternative tools or when to use them, but the context is clear enough for an agent to know this is the go-to for listing calendars and obtaining IDs.

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