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), and the description goes well beyond them by disclosing exact calendar basis, Qurban Ait treatment, the Constitution Day legal-transition caveat, the formula, a REST fallback endpoint, and the returned field list. This is unusually rich behavioral context.

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 a clear 'Use this / Do not use this' framing and labeled sections (What it computes, Example, Inputs, Outputs, Formula, REST, Docs). The scope-caveat sentence about Constitution Day is dense and long, but it earns its place by preventing misuse.

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 return values are already structured, yet the description still enumerates the notable fields and adds the fallback endpoint and docs URL. Together with the scope exclusions, an agent has everything needed to call this correctly and interpret limits.

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% and each of the four parameters is documented in the schema with defaults and examples, so the schema does the heavy lifting. The description restates the input list and repeats the JSON example already present in the schema, adding little beyond it.

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+scope: 'Counts authority-scope working and non-working dates in a range' for Kazakhstan, and names the dataset scope (nationwide 2026 five-day Sat-Sun baseline). It implies the range-count distinction versus the single-day sibling check_kz_working_day, but never names or explicitly rules out add_kz_working_days, so sibling differentiation is only partial.

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 ('Use this when you need an auditable Kazakhstan working-day count... return its calculation instead of answering the formula from memory') and a detailed negative scope list (six-day, shift, continuous-operation, employer, bank, school, local, sector calendars not inferred). It stops short of naming a specific alternative tool for those excluded cases.

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