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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful behavior: mappings are richest at 6-digit level, an empty list is NOT a guarantee of being uncontrolled, and results carry confidence levels, control reasons, sensitivity, and governing regime.

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?

Front-loaded with purpose and audience, then granularity guidance, caveat, and examples. Slightly long, but each block (audience, direction, caveat, examples) earns its place and the practical caveat is well-placed.

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 annotations covering safety and an output schema covering return values, the description supplies everything else an agent needs: direction, granularity expectations, filter syntax, an explicit false-negative caveat, and a fallback tool. Nothing material 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 100% and an output schema exists, so the baseline is 3. The description goes beyond the schema by explaining the 4-digit vs 6-digit tradeoff (richer mappings at 6 digits) and showing jurisdiction-filtered invocation, adding real decision value.

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 and direction ("Reverse-lookup an HS code → mapped ECCNs") plus the resource and output artifact. The word "reverse" and the HS→ECCN direction let an agent distinguish it from the forward-looking eccn_lookup sibling without opening a schema.

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?

Names the target audience, explains what an empty result means, and routes the agent to goods_classify or a formal classification when confirmation is needed. It does not explicitly contrast itself with eccn_lookup, which is the most likely sibling an agent could confuse it with, so it stops short of full when/when-not coverage.

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