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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful context beyond them: the authoritative data source, the covered year range with 'special school holidays' as a distinct data category, and per-call pricing on x402/Base mainnet, which an agent needs before invoking a paid tool.

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?

Two sentences, front-loaded with the resource and scope before the use cases and the billing note. The pricing sentence is short and earns its place as operational detail; nothing is padded or repeated.

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?

With only two optional parameters and no output schema, the description carries the burden of explaining returns, which it does at a category level (term dates, holidays, special holidays, boolean school-day result). An agent could decide and invoke correctly, though it does not say how terms and holidays are structured in the response.

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 both the 'date' (YYYY-MM-DD, school-day check) and 'year' (2026-2027, defaults to the date's year or current year) parameters are already fully documented. The description restates the two capabilities but adds no format, precedence, or combination semantics beyond the schema, so the baseline applies.

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 first sentence names a specific resource (South African public school term dates and holidays for 2026-2027) plus the source (Department of Basic Education) and the conditional lookup ('whether a given date is a school day'). It is clearly distinct from services like za_public_holidays or za_is_business_day, though it never names those siblings to make the distinction explicit.

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?

Usage is implied through use-case framing ('useful for family travel, childcare, events and education planning in South Africa') rather than stated as when-to-use rules. It gives no exclusions or routing guidance, e.g. it never says to use this instead of za_is_business_day or za_public_holidays when the question is about business vs school days.

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