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

The annotations already indicate readOnlyHint=true and destructiveHint=false, so safe read-only behavior is covered. The description adds valuable context on return contents: official names in the requested language, chapter, and similarity score. This goes beyond the annotations without contradicting them.

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 tightly written sentences with no filler. The purpose, input variants, return contents, and downstream usage are all packed into a compact description that is easy to scan.

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 read-only lookup tool with one required parameter and no output schema, the description gives enough context: what inputs are accepted, what the response includes, and how the result should be used next. The schema covers length and default constraints, so nothing essential is missing.

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 67%, so the schema already documents query and limit, and the locale enum is self-explanatory. The description reuses 'by description or by code prefix' from the schema and refers to 'requested language' for locale, but adds little new parameter-specific meaning. It does not explain limit further, but that is already covered by 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?

States a specific verb ('Find') and resource ('Harmonised System (HS) customs code'), and clarifies the two accepted input forms: product description or code prefix. It also distinguishes itself from sibling tools by tying its output to the follow-up use of check_dual_use, so an agent can select it without opening schemas.

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?

Explicitly tells the agent when to use this tool ('when the person needs a customs classification for an import, an export or a quote') and what to do next ('then pass the code to check_dual_use'). This gives clear selection and chaining guidance beyond just describing the function.

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