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

Annotations already cover read-only, idempotent, non-destructive, closed-world semantics, so the description sensibly spends its budget elsewhere: deterministic computation, the exact authority event source, dataset/coverage years, the explicit formula, and a REST fallback endpoint with a warning not to guess other paths. This is meaningful context beyond the annotations, though no freshness/rate-limit or error-handling behavior is described.

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?

Front-loads the core directive effectively, but the block is long for a single-date lookup: the full output field list is redundant given a declared output schema, and the 'Example user requests' lines ('Indonesia: National holiday.') add little. The repeated country name is a sloppy artifact.

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?

Covers the essentials an agent needs: what the calculation means, its scope limits, source authority, coverage horizon, and a fallback path. The output-schema redundancy is a minor cost, and nothing critical for correct invocation appears 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?

Only one parameter and the schema covers it at 100% ('Gregorian date in Indonesia coverage'), so the schema carries the semantics. The description's 'Inputs: date (date)' and JSON examples repeat rather than extend what the schema already documents.

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 (checks a date), resource (Indonesia working day), and scope (national holidays plus joint-leave from the three-minister SKB), and names the weekend baseline and 2026-2027 authority events it evaluates against. It is distinguishable from the many sibling check_*_working_day tools by country, though the opening sentence is garbled (repeated 'Indonesia Indonesia') and muddies the first read.

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 ('when you need a deterministic ... schedule') and when-not ('cuti bersama is facultative for private employers', ASN-specific, local/sector/religious-optional schedules not inferred), plus the directive to call it directly rather than answer from memory. It does not point to a specific alternative tool for the excluded cases, so it falls just short of a 5.

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