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

Annotations already declare readOnly/idempotent/non-destructive and closed-world, so the safety profile is covered. The description adds value beyond that by disclosing output behavior: up to 5 candidates sorted by relevance, each carrying 11-digit cccCodeFull, product name, tariff rate with ECFA second-column determination, and input-regulation summary, plus that results match the official page.

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 purpose and output contract are front-loaded, followed by input-quality guidance and next steps. It is fairly dense with several clauses, but nearly every sentence carries actionable information rather than padding.

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 need not detail return values, yet it does convey the candidate shape and matching behavior. Combined with annotations covering safety and a 100%-covered two-param schema, an agent has everything needed to call it correctly.

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%, so the baseline is 3, but the description adds genuine semantic guidance beyond the schema: specificity of the description (brand/model/material/usage) drives accuracy, and the limit caps at 5 candidates. This meaningfully shapes how the agent formulates product_name.

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 (look up Taiwan CCC tariff code candidates by product name/description) and clarifies it mirrors the official search engine. It explicitly differentiates itself from siblings by pointing to lucky_ccc_tariff_lookup for full fees and lucky_import_tax_estimate for tax, so an agent can tell what this tool does versus those.

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?

Clear routing: it says to use this to find CCC candidates, then names the follow-on tools for full details and tax estimation. It also gives a retry condition (add details and re-search when no high-confidence candidate appears). No explicit when-not guidance, but the workflow context is strong.

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