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

Annotations already declare readOnly/idempotent/openWorld=false, so the safety profile is covered. The description adds real behavioral context beyond that: the Qurban Ait first-day convention, the Adilet Constitution Day vs published-calendar discrepancy, the is_working_day formula, and a REST fallback path with a warning not to guess other /api/* paths.

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-loaded with the trigger condition, which is good, but the body is verbose and repetitive ('Kazakhstan Kazakhstan', '2026-2026') and includes a legal-amendment tangent (Adilet Constitution Day / 2026-07-01 transition) whose relevance to a caller is marginal. Some sentences do not clearly earn their place.

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-input, deterministic calculator with an output schema, the description is largely complete: it defines scope, exclusions, the formula, sample inputs, and a fallback endpoint. It redundantly enumerates output fields already covered by the output schema, but nothing an agent needs to invoke it correctly 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?

Only one parameter and schema description coverage is 100%, so the schema already defines 'date' as a Gregorian date in the pinned 2026 schedule. The description reinforces this with two complete JSON argument examples and the pinned-calendar constraint, adding modest value over the schema.

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: check a date against Kazakhstan's pinned 2026 nationwide five-day schedule, and lists the exact computable output (is_working_day, holiday_names, etc.). It implicitly distinguishes check_ from the add_/count_ siblings by saying it 'checks a date', but never names them. A duplicated token ('Kazakhstan Kazakhstan') and dense phrasing slightly blur the opening.

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 when-to-use ('call this tool directly and return its calculation instead of answering from memory or stopping at discovery') and a clear exclusion list (six-day, shift, continuous-operation, employer, bank, school, local, sector calendars are not inferred). It does not name sibling tools like add_kz_working_days or count_kz_working_days, so routing among the family is left to inference.

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