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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds genuine value by signaling a line-by-line breakdown of results and 166-country coverage (useful since no output schema exists), but it says nothing about precision assumptions, what the 2026 tax year means for other years, or how the Gulf no-income-tax path behaves.

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?

Three compact sentences, front-loaded with the most persuasive concrete outputs so the agent immediately sees the result shape. The trailing URL is minor noise, and nothing is padded.

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 10 optional parameters spanning four tax regimes and no output schema, the description should ideally explain how country/region/stateRate/otherRate/social interact or note that only a subset applies per country. It hints at the Gulf special case but leaves that interaction to the schema. Adequate, not complete.

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 one of the 10 parameters is already documented in the schema, including the country-specific quirks (GOSI, provincial tax, progressive state rates). The description's 'the Gulf included' and the Texas/England examples loosely map to country/region selection but add no syntax or conditional guidance beyond the schema. Baseline 3 applies.

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?

The description communicates the tool's function through concrete worked examples ('$75,000 in Texas leaves $61,592.50 after 2026 federal tax and FICA') plus the summary 'Net pay in 166 countries,' which makes the verb (compute net pay) and resource (after-tax salary) clear. However, it never distinguishes itself from close siblings such as income_tax_calculator, salary_calculator, or tax_free_salary_equivalent_calculator, leaving the agent to infer the boundary.

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?

There is no statement of when to use this tool versus the many overlapping salary/tax siblings, and no exclusions or prerequisites. The only implicit signal is the breadth of country coverage, which an agent must interpret on its own.

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