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

Annotations already establish the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description only needs to add context. It does: 'using effective tax rates' signals the output is an approximation rather than an assessed bill, which is genuinely useful expectation-setting for a financial figure.

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, purpose front-loaded, no filler. The return-shape list is partly redundant since an output schema exists, which costs a little space, but it is not verbose enough to be a real problem.

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 two-parameter, read-only estimator with an output schema and full annotation coverage, the description supplies everything an agent needs to call it correctly. The only shortfall is the absent differentiation from sibling tax calculators, which matters more here given the very large sibling set.

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%, including the state enum and the home_value USD description, so the schema already carries parameter meaning. The description only echoes 'by state' and adds no format, default, or supported-state detail beyond the enum. 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?

States a specific verb+resource+scope: 'Estimate annual US property tax by state using effective tax rates.' That is unambiguous and immediately actionable. It stops short of distinguishing itself from the nearby siblings calculate_us_state_tax and calculate_property_tax_fr, which an agent could plausibly confuse with this one.

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?

Usage is only implied by the purpose statement; there is no explicit when-to-use or when-not, and no mention of the alternative US tax tools. The one navigational line ('See list_bundles for related finance-us calculators') points at a browsing tool rather than telling the agent when this calculator is the right pick.

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