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

Annotations already provide readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds meaningful behavior beyond annotations: demo-mode limits to 2026 and standard filing statuses, the returned output set, and the disclaimer 'Reference data only, not advice.' No contradiction with annotations.

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 tight sentences: the first states the core computation, the second lists outputs, and the third gives limitations and disclaimer. Every sentence earns its place with no filler or repetition.

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 usefully lists the returned values. The 6 parameters are mostly covered by schema descriptions plus the added demo-mode constraints. Minor gaps remain, such as exact filing-status valid values and the meaning of 'demo mode,' but nothing blocks correct invocation.

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 67%, and the description compensates by explaining that state tax is optional, that gross income/filing status/year/deductions drive the calculation, and that demo mode only supports 2026 with standard filing statuses. The schema already covers additional_income, so the overall parameter picture is reasonably complete.

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 states a specific verb and resource: 'Compute progressive federal (and optional state) tax owed from gross income, filing status, year, and deductions.' It also lists concrete outputs (tax, marginal/effective rate, take-home, per-bracket impact), which clearly distinguishes it from sibling reference tools like tax_federal_brackets or tax_summary.

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 intended use is implied by 'Compute progressive federal (and optional state) tax owed,' so an agent can infer this is for tax liability calculations rather than bracket lookups or deadlines. However, the description gives no explicit when-to-use vs alternatives and does not mention any sibling tool or exclusion.

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