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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds genuinely useful behavioral context beyond that: it is deterministic, it does not infer substitute/sector/local schedules, it discloses the exact formula, a REST fallback endpoint, and docs. No contradiction with 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?

Front-loaded with the when-to-use clause, but the body is padded: a duplicated 'Poland Poland', repeated JSON examples already in the schema, a restated formula, and an output field list that the output schema covers. It is informative but does not earn every line.

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 single-parameter, read-only, deterministic check tool with an output schema, the description supplies more than enough: scope, exclusions, formula, fallback endpoint and docs. The enumerated output fields are redundant given the output schema, but nothing an agent needs to call it correctly 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?

One parameter with 100% schema description coverage, so the schema already documents 'date' as a Gregorian date in Poland coverage. The description repeats example values ({"date":"2026-12-24"}) but adds no syntax or format meaning beyond the schema. Baseline 3 applies.

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 (checks) and resource (a date against Poland's nationwide statutory holidays and weekend baseline), and scopes it to 2026-2027. It distinguishes itself from the many sibling country check tools by naming Poland, though the 'Poland Poland' duplication is sloppy. It stops short of explicitly contrasting with add_pl_working_days or count_pl_working_days.

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?

Strong explicit routing: 'Use this when you need a deterministic ... result' and 'Do not use this when nationwide statutory holiday list only', listing excluded scopes (Saturday substitute dates, individual work schedules, employer/sector/school/bank/local). It also instructs the agent to call directly rather than answer from memory. It does not name sibling alternatives by name, so not a full 5.

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