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

With no annotations, the description fully discloses pricing ($0.05/call), determinism, source citation, and the guarantee that errors and unverified rules are never billed. This goes beyond basic expectations and clearly communicates the tool's trustworthy and safe behavior.

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 compact—three sentences—and all information is valuable: purpose, methods, pricing, and reliability. It is front-loaded with the core functionality and avoids redundancy or fluff.

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 7 parameters, no output schema, and low schema coverage, the description lacks essential operational details. It does not explain the output format, how to structure transactions, or the permissible method values. The description is insufficient for an agent to correctly invoke the tool without additional information.

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 only 14%, and the description provides minimal explanation of parameters like year, as_of, method, opening, transactions, and other_taxable_income_yen. It mentions methods and disposal types but does not clarify how to populate the transaction array or the meaning of 'opening'. The description fails to compensate for the low schema coverage.

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 explicitly states the tool computes Japan crypto-asset tax, specifying the NTA total-average or moving-average method and details on disposals and fees. It clearly distinguishes from sibling tax tools by focusing on crypto-assets, with a specific verb and scope.

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 clearly indicates the domain (Japan crypto-asset tax) and provides context on methods and scope, but does not explicitly mention when not to use or alternatives. Since many sibling tools exist, excluding non-crypto tax scenarios could be helpful, but the context is clear enough for a 4.

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