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

No annotations are provided, so the description carries the full burden. It does add genuinely useful behavioral content by disclosing the formula constants (30% uplift, 80% deduction), but it never states that this is a pure, side-effect-free calculation, whether the nexus fraction is capped at 1.0, or what happens when overall_expenditure is zero or less than qualifying_expenditure.

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?

A single sentence with no filler, and the computation constants and output (effective rate) are front-loaded so an agent can grasp the tool's shape at a glance.

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 100% schema coverage and only three flat parameters the inputs are adequately covered, and the description names the two returned figures even without an output schema. However, for a quantitative calculator it omits the formula's edge behavior (capping, zero-expenditure handling) and what is returned when the optional qualifying_profit is omitted.

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%, so all three parameters (including the optional qualifying_profit) are already documented in structured form, which sets the baseline at 3. The description adds no meaning beyond the schema: it does not explain the role of qualifying_profit in the computation or how it interacts with the optional status.

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 (compute) and specific outputs: the nexus fraction with the 30% uplift and 80% deduction, plus the resulting effective corporate tax rate. The Cyprus IP box domain is unambiguous and the sibling tools (audit test, lookups, VAT registration) inhabit clearly different domains, so no in-description differentiation is required.

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?

Usage is only implied by the domain terminology; there is no statement of when this calculation applies (e.g., when an asset generates qualifying IP income) or any preconditions such as overall expenditure being at least the qualifying expenditure. No alternatives are named, though the sibling set makes an alternative unlikely to be confused.

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