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

No annotations are provided, so the description must carry the full burden. It discloses that values are approximate and from public sources, and that it's not tax advice. It also mentions 'FREE' which hints at no cost. However, it does not describe whether the operation is read-only (presumed), any authentication requirements, or rate limits. The behavioral transparency is adequate but not thorough.

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 English sentence (plus a Japanese note) that packs all essential information: purpose, content, source quality, and disclaimer. It is front-loaded with 'FREE' and immediately states what the tool returns. Every phrase adds value with no wasted words.

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?

Given a single optional parameter and no output schema, the description provides a comprehensive list of returned values and their nature (approximate, sourced). It includes a disclaimer. It could explicitly state the return format (object with keys) but 'structured tax parameters' implies organized data. The Japanese note adds completeness for its target audience.

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% with a detailed description for tax_year: 'Tax year for epoch annotation of pending-reform rules, e.g. 2026 or 2028.' The tool description adds further context by listing the specific tax items returned, which complements the schema. No ambiguity remains.

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 lists what the tool returns: progressive income tax brackets, resident tax, reconstruction surtax, 2028-reform figures, and filing threshold. The title 'Japanese tax parameters (brackets, rates, thresholds)' and content distinguish it from sibling tools like get_rule_pack and get_tax_rule, which focus on rules rather than parameter values.

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 starts with 'FREE' indicating no cost, and includes disclaimers about approximate values and not being tax advice. It implicitly tells the agent this tool is for retrieving snapshot tax numbers, not for detailed rule lookups. While it doesn't explicitly contrast with siblings, the term 'parameters' vs 'rules' provides adequate guidance. A minor gap: no direct 'when to use' statement.

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