List calendars

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open world), so the bar is lower, and the description adds a concrete auth prerequisite (Calendars scope) that the annotations do not convey. It stops short of noting that results come from a remote mailbox that may include shared calendars, which the openWorldHint implies.

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 short sentences, with the resource and returned fields front-loaded and the scope requirement second. No filler or redundancy.

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?

With no output schema, the description usefully names the returned fields and the required scope, which is most of what an agent needs for a zero-argument read tool. Minor gaps remain: whether shared/delegated calendars are included and how results are ordered or paginated.

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 tool takes zero parameters, so the baseline is 4; there is no input semantics to compensate for. The listed fields describe output rather than parameters, but they do not mislead.

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?

States a specific verb and resource ('List the calendars in the mailbox') and enumerates the fields returned (id, name, owner, editability), which separates it cleanly from siblings like list_events or get_free_busy. An agent knows exactly what this tool yields without opening a 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 one hard precondition ('Needs the Calendars scope') but never says when to choose this over siblings such as list_events, nor any exclusion. Usage is implied by the name and the mailbox scoping rather than stated.

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