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

The description adds value beyond the readOnlyHint and openWorldHint annotations by specifying the calculation basis ('current official progressive brackets') and the exact outputs (tax owed, effective rate, marginal rate, take-home pay). It does not contradict annotations. Slight gap: doesn't mention that deductions default to standard, but schema covers that.

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?

The description is a single sentence with a clear front-loaded purpose and a country list. The list of 21 countries is useful but could be more compact; however, it's not excessive. The numeric mismatch (24 vs 21) is a minor blemish.

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?

For a calculator tool with only three parameters and no output schema, the description covers the main purpose, outputs, and country scope. It lacks explicit mention of tax year or residency assumptions, but overall it is sufficient for an agent to select and invoke it. The country count inconsistency is the main gap.

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?

All three parameters have schema descriptions covering 100% of the semantics, with the deduction parameter already explaining its default behavior. The tool description adds no additional parameter meaning beyond the schema, so the baseline score of 3 is appropriate.

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 clearly states the tool calculates personal income tax and lists the countries covered, along with the outputs it produces. However, it claims '24 countries' but the input schema enum contains only 21 countries, creating a minor factual inconsistency that could mislead an agent about coverage. It also does not explicitly differentiate from single-country sibling tools.

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?

No explicit guidance about when to use this tool versus the many country-specific income tax tools (e.g., china_income_tax_salary, income_tax_hong_kong, income_tax_singapore). The description implies usage for the listed countries but does not provide when-not-to-use or alternative recommendations.

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