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

With no annotations, the description carries the full burden and does disclose meaningful behavior: the honoring of national and optional regional holidays, configurable weekend days, and paid-per-call billing via x402 (USDC on Base). It does not describe rate limits, error behavior, or what a response looks like, which keeps it short of a 5 for an unannotated tool.

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 capabilities are front-loaded in the first sentence, followed by usage guidance and payment terms. It is dense and long, but each sentence carries distinct information; no filler sentences are present.

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 all four operating modes, the regional-holiday and weekend configurability, and the payment gate, which is enough for an agent to invoke it correctly. Since no output schema exists, it is slightly thin on return shapes (list vs. boolean vs. computed date vs. count), but the modes make those outcomes largely inferable.

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 100%, so each of the 8 parameters is already documented with format and defaults (ISO2 country, YYYY-MM-DD, weekend day numbers, optional region). The description adds mode-to-parameter context (e.g., add/until drive the arithmetic modes) but no syntax or constraint details beyond the schema, making the baseline 3 appropriate.

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 (public holidays for 200+ countries, regions and states) and enumerates the exact operations: list a year's holidays, check business-day status, add/subtract N business days, and count business days between two dates. An agent can tell immediately what the tool computes without opening the schema. Sibling differentiation is unnecessary here since no sibling tools exist.

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 states clear triggering contexts: computing a payment, delivery, or legal deadline in business days, or checking whether a date is a public holiday in a given country or region. It gives no explicit exclusions or alternatives, but with no sibling tools there is nothing to exclude against, so the practical guidance is strong.

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