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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds valuable beyond-annotation context: auditability, authority-scope limitations, the exact formula, non-inferred schedule types, output fields, and a direct REST fallback. This is rich behavioral disclosure without contradicting annotations.

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 front-loaded with usage guidance and organized into labeled sections, which helps scanning. However, it is overstuffed for a simple four-parameter calculator, duplicating output fields and a trivial formula that are already covered by the output schema and input schema. Every sentence does not earn its place.

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 calendar complexity, the description is complete enough for correct invocation: it covers scope, exclusions, inputs, outputs, formula, REST fallback, and documentation. Although the output schema exists and makes the output list redundant, nothing essential for selecting or calling the tool is missing.

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 schema already documents all four parameters, including dates and inclusion flags. The description restates the inputs and provides a complete JSON example, but adds little semantic meaning beyond what the schema and its examples already provide. Baseline 3 is 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 states a specific verb and resource (count Poland working days) and scope (working and non-working dates in a range). It distinguishes this from formula-memory answers and discovery, and clarifies it is for authority-scope counts rather than broader statutory-only lists. An agent can tell it apart from add/check working-day siblings by the range-counting 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?

It gives explicit when-to-use guidance and a clear when-not-to-use condition ('nationwide statutory holiday list only'). It also lists several excluded schedule types that are not inferred. However, it does not name a specific sibling alternative for those cases, so the routing guidance is strong but not fully explicit.

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