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

Annotations already cover safety (readOnly, idempotent, non-destructive), but the description adds real behavioural value: the method (bisection), the precision guarantee (to the cent), and the fact that it returns the full breakdown PLUS the remaining difference to the target — which tells the agent the target may not be exactly achievable. No performance or convergence-time disclosure keeps it from a 5.

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?

Two tightly written sentences with zero filler. The core purpose and precision guarantee are front-loaded, and the return-value sentence earns its place by clarifying the 'remaining difference' output.

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?

An output schema exists, so return values need no elaboration, and the description still usefully notes the remaining-difference field. With 6 params at full schema coverage and rich nested docs, nothing critical is missing; the only gap is no explicit statement of country/period scope that the schema carries.

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%, including rich nested DE/UK profile docs, so the baseline is 3. The description adds only the notion of a 'target net' and 'gross pay', which the schema titles already convey; no period, country, or year semantics are elaborated beyond what the schema documents.

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 (find gross pay for a target net) with a precise scope qualifier: the SMALLEST gross to the cent. Combined with 'bisection over the same engine as /net', the agent immediately understands this is the inverse of the net calculator, distinguishing it from calculate_net_salary and compare_net_salaries.

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 inverse framing ('net pay reaches the target') makes the when-to-use case clear relative to calculate_net_salary, and the 'same engine as /net' note signals shared semantics. However, it never explicitly names the sibling to use when going the other direction, nor states any exclusions or prerequisites (e.g. country coverage), so it stops short of a 5.

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