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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description does not contradict them. The description adds behavioral context by specifying the return format (dates in YYYY-MM-DD), the bilingual names, and that bridge holidays (feriados puente) are not included, which is a meaningful limitation beyond what annotations provide. It does not cover error handling or edge cases, but the added detail justifies a score above baseline.

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 description is compact, informative, and well-structured. It front-loads the core purpose, then gives usage guidance, return format, and a caveat—all in four sentences with no redundant phrasing. Every sentence contributes value, making it an example of efficient communication.

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?

Given the tool's simplicity (single parameter, read-only, no output schema), the description is complete. It explains what is returned (national holidays), the format (dates and names), the language coverage, and the notable omission (bridge holidays). This is sufficient for an agent to understand the tool's behavior without needing an output schema.

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?

The input schema already describes the 'year' parameter with a 100% coverage, including an example ('2026'). The description adds minimal semantic detail beyond saying 'any given year,' which is already implied. Since schema coverage is high, the baseline of 3 is appropriate, and the description does not meaningfully enhance parameter comprehension.

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 clearly states the tool 'Returns Argentine national public holidays for any given year,' which specifies the exact verb (Returns), resource (Argentine national public holidays), and scope (any given year). It also distinguishes from sibling tools like get_brazil_holidays by focusing on Argentina. The additional details about date format and bilingual names further clarify the purpose.

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 description explicitly says 'Use this tool when calculating delivery dates, scheduling appointments, computing working days, or any task requiring knowledge of non-working days in Argentina,' providing clear usage contexts. However, it does not explicitly name alternative tools for other countries or state a 'when not to use' scenario beyond the note that bridge holidays are excluded, which implies a limitation but not an alternative. This is clear context without explicit exclusions.

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