List calendars

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds that it 'Returns 50 by default' (pagination limit) and further explains the return payload fields. These are behavioral traits not in the annotations, adding value beyond the structured metadata. No contradictions found.

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 only two sentences, with the core purpose front-loaded and the default behavior and chaining guidance included in the second sentence. No fluff, no redundant repetition of schema or annotations. Every sentence 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 simple list tool with one optional parameter and no output schema, the description is complete. It tells the agent what it returns (fields), the default page size, how to use the results (via calendarId), and implicitly that it operates on the signed-in user's calendars. Nothing essential 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 schema description coverage is 100%, and the only parameter `top` is fully documented in the schema (maximum, default, meaning). The description repeats the default of 50 but does not add any new meaning beyond the schema. Per the rubric, a baseline of 3 is appropriate when the schema already covers parameter semantics.

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 verb 'Lists' and the resource 'the signed-in user's calendars', enumerating the fields returned (id, name, colour, owner, edit/share flags). This is specific and distinguishes it from sibling tools like calendar_get_event (which fetches a single calendar) and calendar_list_events (which lists events). The scope 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?

The description provides clear usage context by saying 'Use the returned id as calendarId in calendar_list_events', which tells the agent a common workflow. It does not explicitly contrast with alternatives like calendar_get_event, nor state when not to use it, but the chaining instruction gives a definite purpose. This merits a 4 (clear context, but no exclusions).

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