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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so safety is covered. The description adds genuine context beyond that: the OPM 2026-2027 dataset scope, the pinned-year constraint, the per-date accumulation formula, and a REST fallback path. It stops short of noting rate limits or source staleness beyond dataset_version, but this is strong.

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?

Well front-loaded: the when-to-use, exclusion, computation, and example precede the mechanical sections. It is somewhat long, and the enumerated Outputs duplicate what the output schema already provides, but every section is labeled and scannable rather than padded prose.

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 4-parameter calculation with an output schema and rich annotations, this description is complete: it names the calendar, the date range semantics, the fallback endpoint, and docs. Nothing an agent needs to invoke it correctly (or to reject alternatives) 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?

Schema coverage is 100%, so the schema already documents all four parameters (baseline 3). The description goes further by restating the inputs with types and optionality and providing a complete, copy-ready JSON argument example, which usefully clarifies the boolean participation 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?

States a specific verb+resource (count US federal working days) and scopes it precisely: an auditable federal-employee/office count for a pinned year using the OPM 2026-2027 schedule. This distinguishes it from the many sibling count_*/check_*/add_* working-day tools by naming the exact calendar and behavior.

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?

Explicitly covers when to use ('call this tool directly... instead of answering from memory'), and when NOT to use (state/local/private/exchange/alternate schedules). It also gives a concrete example request, leaving no ambiguity about routing versus check_us_federal_working_day or add_us_federal_working_days.

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