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

Annotations already cover the safety profile (readOnly, non-destructive) and openWorldHint, and the description adds real value beyond them: results are relative to today and each entry reports how many days away it is. That return-shape disclosure matters since there is no output schema, and the time-relative behavior is consistent with idempotentHint=false. It says nothing about country-code resolution failures or result ordering.

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?

Three short sentences: what it returns, when to use it, one call example. Front-loaded with the return semantics and free of filler.

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 two-parameter read tool with no output schema, the description covers purpose, triggers, output content (holidays plus days-away), and a sample call. Remaining gaps — limit bounds/default, ordering, and behavior for an invalid country — are modest but real.

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 only 50% (limit is bare, country documented only as 'Country code or name'). The example {"country":"Japan","limit":3} usefully demonstrates that a full country name is accepted alongside codes and that limit is a simple result count, partially compensating for the gap. It does not mention limit's default of 5 or its 1-10 cap.

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 resource and scope: upcoming public holidays for a country, computed from today, including days-away. The 'from today' scope implicitly separates it from the sibling public_holidays, but it never names or contrasts that sibling explicitly, so differentiation requires inference.

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?

The 'Use when' clause supplies two concrete natural-language triggers (next holiday in Japan, next long weekend in France), which is clear routing context. It stops short of exclusions or naming is_public_holiday / public_holidays as the alternatives for other cases (e.g. checking a specific date or listing a full year).

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