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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real context beyond that: the exact formula, the coverage boundary (federal statutory + 2026 transfer days only), and the fact that regional/sector schedules are not inferred. No return-value explanation is needed since an output schema exists.

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 use/don't-use guidance, which is good, but the prose is repetitive ('Russia Russia', restated coverage clauses) and pads with outputs, formula and docs links that partly duplicate the structured schema. Much of it earns its place, but trimming would help.

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 a single required parameter, an existing output schema and rich annotations, the description supplies the remaining needed context: scope limits, the compute rule, and a REST fallback path. Only minor gaps remain, e.g. no explicit alternative-country routing guidance.

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% and the single date parameter is well documented in the schema, which sets the baseline at 3. The description goes slightly further by supplying complete JSON argument examples ({"date":"2026-01-05"} etc.), giving the agent a ready invocation shape.

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?

States a specific verb and resource: checks a date against the Saturday-Sunday weekend baseline plus exact 2026 federal authority events, and enumerates the output fields. It is clear what the tool does, though it does not explicitly name a sibling country tool as the alternative; the garbled 'Russia Russia' phrasing is a cosmetic flaw.

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?

Opens with a clear 'Use this when...' trigger and follows with an explicit 'Do not use this when...' scope block (regional/local/employer/bank/school calendars not inferred; future years need a refreshed package). It also tells the agent to call the tool rather than answer from memory. It stops short of naming a specific alternative sibling for out-of-scope dates.

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