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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world scope, so the safety profile is covered. The description adds a useful non-schema fact ('Free') and enumerates the three questions it can answer, but it never explains how the two parameters select among those three modes (e.g. what add_days=0 yields vs. the is-a-working-day check), which is the key behavioral ambiguity.

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?

One front-loaded sentence opens with the use case and packs the three operations into a compact clause, with zero filler. Slightly dense parenthetical phrasing keeps it from being maximally scannable.

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?

With no output schema, the description does list the three answerable questions, which implicitly covers the return shape (a judgment, a date, a computed date). It is nearly complete for a two-param read-only tool, though it could state explicitly what is returned for each mode.

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 coverage is 100% and both parameters carry descriptions plus examples, so the baseline is 3. The description's phrase 'the date N working days later' loosely maps to add_days, but it does not clarify the mode selection (default add_days=0) or date-format expectations beyond what the schema already says.

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+resource: computing due dates in Romanian working days, with three concrete capabilities (is-it-a-working-day, next working day, date N days later) and a real example (e-Factura upload deadline). It is distinguishable from siblings like ro_holidays or ro_tax_deadlines by emphasizing working-day arithmetic, though it never names those neighbors.

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 e-Factura example implies the use case well, and 'Free' signals no cost barrier. However there is no explicit when-to-use/when-not guidance and no reference to the closely related siblings (ro_holidays, ro_tax_deadlines), so the agent must infer which tool fits which question.

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