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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so safety and determinism are covered elsewhere. The description contributes one genuinely useful behavioral detail — '(computed)' — implying results are derived rather than fetched from a fixed holiday table, but says nothing about how observances vs. eves are labeled in the output.

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?

A single tightly written sentence that front-loads the verb and resource with zero filler. Every phrase carries information.

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 read-only, single-parameter tool the description is close to sufficient, but 'year' is not a required parameter and the description never says what happens when it is omitted (current year? all years?). That is a real gap an agent could trip on.

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 coverage is 100% for the single 'year' parameter and the schema already documents its 1900-2200 range. The description only implies 'for a year' without adding format, default, or out-of-range behavior, so the baseline 3 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 description gives a specific verb ('List') and a well-scoped resource ('Swedish public holidays, eves and observances for a year'), so an agent knows exactly what it returns. It does not, however, distinguish itself from the closest sibling, swedish_date_info, which could plausibly overlap.

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?

There is no explicit when-to-use guidance and no mention of alternatives, despite swedish_date_info sitting in the same sibling list as a potential overlap. A caller must infer the use case entirely from the noun phrase.

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