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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so safety is covered. The description adds useful behavioral scope by identifying federal tax, the 2026 tax year, the worked example, and specific tax rules handled; it still omits assumptions such as state-tax exclusion and output breakdown.

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 three compact sentences with no wasted wording, and the example is front-loaded. The main weakness is that the example appears before a direct general-purpose statement.

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 seven-parameter calculator with no output schema, the description gives only a single example result and a feature list. It does not specify what the response contains (tax owed, effective rate, breakdown, assumptions), leaving an output-contract gap despite rich schema coverage.

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 the input schema already documents all seven parameters thoroughly. The description adds no parameter-specific syntax or meaning beyond the feature list, so baseline 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 concrete example ('$15,000 long-term gain... $2,250 in 2026 federal tax') and capital-gains-specific topics make clear this computes U.S. federal capital gains tax. It distinguishes itself from the generic income_tax_calculator, though it never states the overarching verb explicitly.

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 lists scenarios the calculator handles (short vs long term, 3.8% NIIT, home sale exclusion, expat stacking rule), which implies when it is relevant. However, it gives no explicit when-to-use guidance or comparison to alternatives such as income_tax_calculator.

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