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

Annotations declare readOnlyHint=true and destructiveHint=false, correctly signaling a pure computation. The description adds valuable behavioral detail: it enumerates the tax jurisdictions handled (England/Wales/NI vs Scotland), output granularity (yearly/monthly/weekly), and that it returns employer NI and total cost. That is meaningfully more than the annotations provide, though it omits assumption disclosures (e.g. which tax-year rates are current, treatment of Scottish NI).

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 dense sentence that front-loads the core purpose and then lists the computed components. Efficient with no filler, though the run-on structure and one very long clause slightly reduce scannability.

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 correctly enumerates the return contents (breakdown by component plus yearly/monthly/weekly take-home and employer cost), and it names the tax region split. It stops short of stating default tax-year behavior or rounding/assumption caveats, so a small gap remains for a multi-jurisdiction financial calculator.

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 every parameter is already documented, setting the baseline at 3. The description mentions student loan and pension contributions and the Scottish/UK tax distinction, which maps to parameters, but adds no syntax or default semantics beyond what the schema provides.

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 (calculate) and resource (take-home pay from a UK salary) with full scope detail: income tax by band, National Insurance, student loan, pension, and employer cost. An agent can distinguish this from siblings like calculate_student_loan_repayment or calculate_pension_tax_relief because this tool aggregates them into a take-home figure.

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 usage (UK salary take-home) but offers no explicit when-to-use vs alternatives such as calculate_gross_salary_for_take_home or compare_salary_and_dividends. The inverse-direction sibling (gross from take-home) and the salary-vs-dividends comparison sibling are the most likely confusions, and neither is addressed.

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