list_calendars

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

Annotations already establish the tool is read-only, idempotent, and non-destructive. The description adds useful behavioral context beyond those annotations by specifying the output contents, the optional calendar scoping, and the exception-count cap. It does not fully describe output shape or pagination, but the safety profile is already covered.

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 compact sentences with no filler. The primary behavior and return contents are front-loaded, and the optional usage guidance is delivered in a brief second sentence. Every phrase 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 read-only listing tool with simple scalar parameters, the description is reasonably complete: it states what is listed, how to narrow to a single calendar, and the exception limit. The main missing piece is a direct explanation of the required `path` parameter, but the overall complexity is low and no output schema exists to contradict or supplement.

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?

With 0% schema description coverage, the description must compensate, and it partially does: it explains the `calendar` parameter (name or id) and `exceptions` (limit on exception dates). However, the required `path` parameter is only implied by 'in a schedule file' and is never explicitly tied to the path argument, leaving a meaningful gap.

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 uses a specific verb ('List') with a clear resource ('work calendars in a schedule file') and enumerates the exact fields returned: work week, hours per day, exception counts, and activity usage. This level of specificity clearly separates it from sibling tools like list_activities or schedule_summary, even without naming them.

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 to use the tool: to get calendar definitions and usage counts. It also explains the optional narrowing behavior ('Pass calendar for one calendar with its exception dates'), though it does not explicitly contrast this with alternatives 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.