list_calendars

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly reveals that app identity only sees invited calendars and that the OAuth scope is required—auth and visibility constraints that go beyond the raw schema. However, it does not mention pagination behavior or return format, leaving some gaps.

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 two short sentences. The first is front-loaded with the core purpose, and the second adds essential requirements and limitations. Every word earns its place with no redundancy or filler.

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 tool has no output schema and no annotations, so the description should compensate by explaining return values and behavioral nuances. It provides important auth context but omits the structure of the returned calendar list and does not elaborate on how sync_token affects results beyond the schema's terse 'Incremental sync token (optional)'. This leaves an agent partially unprepared to consume the output.

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 100% description coverage for all three parameters, including details like page_size minimum (50) and the sync_token purpose. The description itself adds no parameter-specific meaning, so the baseline score of 3 applies as the schema does the heavy lifting.

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 action ('List the current user's calendars') and enumerates the exact resource types (primary + shared + subscribed). This distinguishes it from sibling tools like 'list_calendar_events' and 'get_calendar_event' by focusing on the calendar list rather than events or a single calendar.

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 provides clear context for when the tool is applicable: it requires a User Access Token (UAT) and the `calendar:calendar:readonly` scope, and notes that app identity only sees calendars it was explicitly invited to. This implies usage prerequisites and limitations, though it does not explicitly name alternative tools or state when not to use it.

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