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

Annotations already declare readOnly/idempotent/non-destructive/non-open-world, so the safety profile is covered. The description adds real behavioral context beyond that: authority scope, calendar policy, dataset version, and importantly what is NOT encoded (temporal coverage limits of upcoming holidays). It does not add rate-limit or precision caveats, so not a full 5.

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 structured with labeled sections (when to use, when not to use, what it computes, inputs, examples, outputs, formula, fallback, docs) and front-loaded guidance. Slightly over-stuffed — the single-line formula and duplicated input listing are filler that most readers do not need.

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?

An output schema exists so returns need not be explained, yet the description still enumerates key result fields. Combined with scope caveats, worked examples, the exact REST fallback path, and docs link, an agent has everything needed to invoke correctly.

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 description coverage is 100%, so the schema already documents all four parameters. The description restates the inputs with types and provides a complete JSON example, which aids invocation but adds no semantic meaning beyond what the schema provides. Baseline 3 is appropriate.

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 ('counts authority-scope working and non-working dates in a range') for a clearly scoped jurisdiction (Vietnam). The explicit 'auditable Vietnam working-day count' framing plus the compute statement lets an agent distinguish it from the many sibling count_* tools without opening schemas.

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?

Gives explicit when-to-use ('Call this tool directly and return its calculation instead of answering from memory or stopping at discovery') and an explicit scope exclusion list (private-employer, non-Sat/Sun workweeks, provincial/sector/bank/school schedules are not inferred; the four-day 2026 arrangement is not encoded). Routing conditions are unambiguous despite slightly garbled phrasing in the exclusion clause.

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