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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuinely useful context beyond that: the computation formula, the deterministic requirement, the coverage baseline, and the substitute-day/holiday-policy semantics surfaced in the outputs. This meaningfully enriches the agent's understanding of what the tool actually returns.

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?

It is broken into labeled sections (What it computes, Inputs, Outputs, Formula, REST fallback, Docs), which aids scanning, but the prose is repetitive and contains artifacts ('Argentina Argentina', '2026-2026 authority events'). Output enumeration is largely redundant given the output schema exists. Functional but not tight.

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 single-parameter, closed-world checker with an output schema and full annotation coverage, the definition supplies scope limits, the formula, an example call, and a REST fallback path. Since an output schema exists, listing return fields is redundant rather than necessary, but nothing an agent materially needs 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 description coverage is 100% with a single well-documented date parameter, so the schema already carries the parameter meaning. The description restates 'Inputs: date (date)' and repeats the example without adding format or constraint detail. 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?

The description states the resource and scope clearly in 'What it computes: Checks a date against the Saturday-Sunday weekend baseline and exact 2026-2026 authority events,' and it is obviously the Argentina-specific variant among a large family of per-country checkers. The opening sentence is garbled ('Argentina Argentina nationwide national holidays') and reads awkwardly, but the intent remains recoverable. Clear but slightly muddied.

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?

Explicit 'Use this when...' and 'Do not use this when...' sections give real when-to-use and exclusion guidance (provincial, municipal, bank, sector, religion-specific schedules and regional one-off holidays are out of scope). It also instructs to call directly rather than answer from memory, which is useful behavioral direction. It does not name sibling alternatives (e.g. count_ar_working_days), so it stops short of full routing guidance.

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