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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), so the bar is lower, yet the description still adds real value: live computation by the same-operator calculators, the upstream page as source, the returned assumptions, and the critical limitation that Spain (es) answers covered:false. It stops short of describing latency, failure behavior, or rate limits.

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?

Purpose and supported countries are front-loaded, then parameters, then return shape, with the Spain caveat last. It is a dense, somewhat run-on single paragraph, but almost every clause carries information and nothing is 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?

With no output schema, the description carries the return-value burden well, enumerating gross/net/deductions, annual+monthly figures, the breakdown typing (tax/social/contribution/repayment), effectiveRate, tax year, currency, assumptions, and source. The es covered:false caveat closes the main coverage ambiguity.

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%, so the schema already documents all seven parameters, defaults, and enums; the description largely restates these (gross annual-by-default, US state/filingStatus, CA province, UK region). Baseline 3 is correct because the schema does the heavy lifting and the description adds little param-level detail beyond it.

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 ('Net salary after income tax and social contributions') and scopes it precisely with the ten supported country codes and the source calculators. An agent can immediately distinguish this from a sibling like uk_rates_lookup (rate lookup) versus a full take-home calculation.

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 description implies when to use it (need net pay given a gross salary) and documents period/country options, but never names an alternative tool or states when NOT to use it. No explicit routing guidance against the sibling tools, so usage is only implied.

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