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

The description reconciles the unusual readOnlyHint=false by disclosing that the call 'uses one read and saves the result in the user's Puley history' — a real side effect an agent should know about, and one the annotations alone would leave confusing. It also sketches the response contents (holidays, applicable regions, the next upcoming one). It does not cover error behavior or empty-result handling.

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 capability is front-loaded and every parameter gets a compact, useful clause. The sentence is slightly run-on and the phrase 'with the regions each applies to, and the next one' is a bit tangled, but nothing is wasted.

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 four-parameter, no-output-schema tool this is nearly complete: both invocation modes, defaults, accepted formats and the notable history side effect are all stated. Only error/empty cases and a clearer picture of the returned structure are 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?

With 0% schema description coverage, the description carries the full burden and does so: country accepts a two-letter code or a name (US, GB, IN, DE, Scotland), year defaults to the current year, date takes an ISO-style value like 2026-12-26, and region takes a state or subdivision code (CA, SCT, BY). This adds concrete format and example meaning that the bare schema lacks.

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 names a specific resource (a country's public holidays for a year, including bank, national and regional days) and a second mode (checking whether a date is a holiday). It is clearly distinct from siblings such as compare_countries or find_events, which cover different subject matter.

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 explains context well by tying each parameter to a use case — pass 'date' to ask whether a specific day is a holiday, pass 'region' to restrict results to holidays that apply there — which effectively signals the two invocation modes. It does not name or exclude sibling tools, so it falls short of full when/when-not guidance.

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