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

Annotations already cover read-only, open-world, idempotent, and non-destructive behavior. Beyond that, the description discloses pricing ($0.05 USDC per successful call), x402 payment on Base, and returned components including an explicit review signal. It does not explain failure behavior or rate limits, but it adds substantial operational context.

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 front-loads purpose and then uses labeled sections for use case, returns, and price. The English/Japanese duplication is redundant for an agent and roughly doubles length, though the structure remains clear.

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 complex OCR-plus-registry resolution tool with no output schema, the description covers purpose, use case, major return categories, and pricing. It leaves the meaning of the 'review signal' and failure behavior underspecified, but input constraints are fully covered by the schema.

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 all nine parameters are already documented in the schema. The description only loosely signals that issuer name/address may be supplied for comparison and that OCR input is supported; it adds no format, precedence, or validation 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?

The opening sentence gives a specific three-step verb sequence—OCR, validate locally, and resolve the issuer against NTA registries—for a Japanese billing invoice. The composite scope clearly separates it from single-purpose sibling tools such as invoice extraction or issuer-only checks.

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 explicitly says to use it when you need invoice OCR plus issuer name/address comparison or completion using NTA public data. It does not state when not to use it or name alternative siblings, so routing between related tools still requires some inference.

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