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

Annotations already cover read-only and open-world safety, but the description adds non-obvious behavior: it costs no points, rejects URLs, returns a privacy_consent_required error until consent is recorded, and lacks stable holiday ids or translations. Disclosing that failure mode and the data-quality limits is exactly the kind of context annotations cannot convey. It stops short of describing result shape or any rate/size limits.

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?

The core purpose is front-loaded in the first sentence, followed by tightly packed caveats about cost, input restrictions, and the consent gate. No sentence is filler, though 'Do not invent that acceptance' is phrased as an instruction rather than a behavior and sits slightly awkwardly.

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 no output schema, the description reasonably omits return-value detail, and annotations cover safety, so the main missing piece is parameter semantics (country code format, year bounds). The cost and consent-gate disclosures are strong, but an agent could still call it with a malformed country value without guidance.

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 0%, so the description carries the burden, yet it only restates 'one country and year' without explaining that country must be a two-letter uppercase ISO-style code or what year range is valid. The only parameter hints come from the schema's own pattern and integer type. This is a clear gap for a two-required-parameter tool.

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 opens with a specific verb and resource ('List basic public holidays'), scopes it to one country and year, and names the backing source and version (Nager.Date community API v4). It also distinguishes itself from the paid Pro feed, so the agent knows exactly which dataset it gets. Sibling differentiation is largely moot since no other tool in the list covers holidays.

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?

It clarifies what the tool does not do (no points spend, no URL, no translations, no stable ids) and warns about the privacy_consent_required gate, which is useful pre-call guidance. However, it never states when to prefer this over an alternative source or when the tool is inappropriate beyond the Pro-feed contrast, so usage is only implied.

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