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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered without the description. The description adds the return shape ({tax, gain_type}) and the rate-treatment split, but nothing about inputs' edge cases, rate-table assumptions, or errors.

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?

Two sentences, zero filler: the tax regime is front-loaded, the return contract follows, and the related-bundle pointer closes. Every clause carries information an agent can act on.

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 an output schema present, the description needn't enumerate return fields (it does anyway). For a four-parameter, enum-bearing, read-only calculator it covers purpose and output shape adequately; only the boundary between this and the property/foreign capital-gains siblings is left implicit.

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 coverage is 100% and all four parameters carry their own descriptions, so the baseline is 3. The description's mention of holding period and filing-status-driven rate thresholds loosely maps to inputs but adds no format, unit, or boundary detail beyond the schema.

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 and resource ('Calculate US capital gains tax') and crisply splits the two regimes (short-term ordinary vs long-term preferential). The 'US' qualifier does useful work against the many international siblings, though it never distinguishes itself from the adjacent calculate_capital_gains_property or the FR variants 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 tells the agent that the short-term/long-term distinction exists and is driven by holding period, which implies when each rate path applies. But it gives no explicit when-to-use guidance, no prerequisites, and the only pointer (list_bundles) is a discovery cross-reference rather than an alternative tool for the same job.

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