list_calendars

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

With no annotations provided, the description must carry the behavioral burden. It does disclose the visibility scope ("can see") and that the response marks the default calendar, which implies a read-only operation, but it says nothing about ordering, whether hidden/subscribed calendars are included, or permission/auth requirements for a listing call.

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?

A single compact sentence with zero filler; the scope qualifier and the default-flag detail are front-loaded and each earns its place.

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 zero-parameter read with no output schema and no annotations, the description covers what the tool returns (visible calendars plus the default marker). Only minor gaps remain, such as result ordering or whether the output is meant to feed the sibling event tools.

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 and there is no parameter meaning left to compensate for. The description correctly implies no input is needed.

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?

"List the calendars this account can see, with which is the default" names a specific verb (List) and resource (calendars) and scopes it to the account's visibility, which cleanly separates it from the event-oriented siblings. It does not explicitly reference those siblings, but the resource distinction is unambiguous.

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?

Usage is only implied: an agent can infer this is the discovery step before calling find_calendar_events or create_calendar_event, but the description never says when to use it, when not to, or that its output feeds the other tools. No exclusions or prerequisites are stated.

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