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

No annotations are provided, so the description carries the full burden. It does add one genuinely useful behavioral fact — a cost of 2 credits — but omits any statement about auth requirements, caching, failure modes, or the shape of the returned duty/measure data.

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?

A single front-loaded sentence with two parallel clauses plus a parenthetical cost note. Every element earns its place and nothing is padded.

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 two-parameter lookup tool with no output schema and no annotations, the description covers the inputs and sketches the returns (duty rates, import measures) adequately. The only real gap is what the measure data actually contains, which an agent must discover by calling.

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% and already explains the 4-digit vs 10-digit distinction, so the baseline is 3. The description does reinforce the role of each parameter (description search vs code lookup), but adds no format examples or precedence rule beyond what the schema states.

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 names a specific verb+resource pair ('Find a UK commodity code') and a second concrete mode ('get duty rates and import measures'), so the agent knows exactly what the tool returns. No sibling in the list touches tariffs or trade data, so disambiguation is implicit but unambiguous.

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?

It clearly splits the two usage modes: pass a description to look up a code, pass a code to get duty rates and measures. It gives no exclusions and does not say what happens if both parameters are supplied or if neither is supplied, which matters since zero parameters are required.

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