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

Beyond the annotations (read-only, idempotent, non-destructive), the description reveals meaningful behavior: it accounts for country-specific weekends (e.g., Friday-Saturday), recognizes national public holidays, names every skipped day, and separates provincial holidays. It also discloses operational requirements such as pricing, prepaid header, and no wallet/API key needed. This is substantial context that aids correct invocation and interpretation of results.

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 dense but well-structured: opening with a memorable hook, then the core operation, country coverage, holiday handling, use cases, required input, and access/pricing details. Every sentence carries useful information and the main functionality is front-loaded. It is slightly longer than strictly necessary due to the pricing details, but those are operationally relevant.

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?

The description covers the tool's purpose, country/range, holiday nuance, use cases, required input, and access requirements, and an output schema exists for return values. Remaining gaps include explicit constraints on parameter combinations (e.g., add vs to exclusion) and exact date format expectations. Overall, it is nearly complete for a moderately complex tool.

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 schema already covers all four parameters; the description supplements it by clarifying the two operating modes: 'add' with a start date, or count between 'from' and 'to'. It reinforces that country is mandatory. However, it still leaves some ambiguity about date formats and whether 'add' and 'to' are mutually exclusive, so the description does not fully resolve all parameter-interaction questions.

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 identifies the tool's function: add business days to a date or count them between two dates, with country-specific weekend and holiday awareness. This is a specific verb-resource pair that distinguishes it from generic date-calculation tools. It also names the required input (country) and the potential use cases, leaving no ambiguity about what the tool does.

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 states the intended use cases ('Built for payment terms, SLAs and delivery dates') and clarifies a subtle decision point: provincial holidays are not treated as national closures and are listed separately so they can be applied when the case is regional. It does not name alternatives, but none of the sibling tools offer similar functionality, and the context is clear enough for an agent to select it. A slightly higher score would require explicit when-not-to-use guidance, which is absent.

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