Who is out?

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

The description adds useful behavioral details beyond annotations: inclusive date handling, each employee appearing once per day, and pending requests counting as a plan. However, annotations mark readOnlyHint as false, and the description does not clarify whether the tool has any side effects or what the return structure looks like, leaving some behavioral ambiguity.

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 compact and front-loaded with the core purpose. Each sentence adds value: main behavior, edge-case semantics, use cases, and free-tier constraint. No filler or redundancy.

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 two-parameter tool with no output schema, the description is nearly complete: it explains scope, date format, per-day deduplication, pending-request handling, and suggested use cases. It only slightly lacks explicit guidance on when not to use it or which sibling to prefer.

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 already describes both parameters with format and inclusivity, achieving 100% schema description coverage. The description restates 'start and end are inclusive YYYY-MM-DD,' which reinforces the schema but adds little new parameter-specific meaning.

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 identifies the tool as a date-range absence query ('Who is out in a date range') with inclusive start/end dates. It is distinguishable from siblings like leave_request or leave_approve, though it does not explicitly differentiate itself from leave_list.

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 explicitly states when to use the tool: 'Use for coverage, calendars and absence summaries.' It provides clear use-case context but does not mention exclusions or alternatives, such as when leave_list or leave_balance would be more appropriate.

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