list_calendars

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

No annotations are supplied, so the description carries the burden; "List" plus "visible to the account" conveys that this is a non-destructive read scoped by account visibility, which covers the core safety profile. It omits pagination behavior, permission requirements, and whether hidden or shared calendars are included beyond the vague "visible" qualifier.

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 front-loaded sentence with no filler, appropriately sized for a zero-parameter list tool. There is no wasted wording, though the brevity comes at the cost of the usage context noted elsewhere.

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 is simple, takes no parameters, and has an output schema that documents return values, so the description does not need to explain results. The remaining gap is that it never tells the agent this call typically precedes event or calendar-scoped operations, but nothing critical to correct invocation is missing.

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 there is nothing for the description to disambiguate and the baseline of 4 applies. Schema coverage is also reported at 100%, so no semantic gap exists on the input side.

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 and resource ("List calendars") plus a scope qualifier ("visible to the account"), so an agent can immediately tell this is a calendar-enumeration tool. It does not explicitly distinguish itself from siblings like list_events or list_labels, but the noun "calendars" is distinctive enough to separate it.

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?

There is no when-to-use guidance, no mention of a typical call sequence (e.g. use this first to obtain calendar IDs for list_events/create_event), and no exclusions or alternatives named. The only hint is the word "List", leaving the agent to infer the discovery role.

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