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

With no annotations, the description carries the full disclosure burden and does well: it specifies the holiday scope (national holidays including Carnaval and Corpus Christi, no state/municipal holidays), defines output per mode, and states the price. It omits edge-case behavior such as what happens if both add and end are provided, or how invalid dates are handled.

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?

A single dense paragraph that front-loads the scope and then enumerates the three input modes before closing with the price. Every sentence carries essential information; no 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 simple 3-parameter utility with no output schema and no annotations, the description covers the key behaviors: holiday scope, output semantics per mode, and pricing. It falls short of fully specifying the return structure and edge cases, but is adequate for correct invocation.

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 the baseline is 3. The description adds meaning beyond the schema by clarifying that end is exclusive and by describing the return for each parameter combination, which the schema does not provide.

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?

Identifies the resource (Brazilian business days) and explains exactly what is returned for each parameter combination, making its function clear. Lacks an explicit verb at the start, but the mode descriptions leave no ambiguity about what the tool computes.

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?

Provides clear context for each input mode: 'With only date', 'With add', 'With end'. This tells an agent how to invoke the tool for the desired result. No alternative date tools exist among siblings, so no when-not-to-use guidance is needed.

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