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

With no annotations supplied, the description carries the full disclosure burden. It does contribute real behavioral context — that this is a diagnostic gate and performs no tax math, implying a read-only screening operation — but it says nothing about what the gate returns (pass/fail, thresholds, per-regime breakdown), whether results are deterministic, or how the 'both' regime combines outputs.

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 short sentences with zero filler, and the regime scope is front-loaded before the operational caveat. Every clause earns its place, including the 'no tax math' disclaimer.

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 seven-parameter diagnostic with no output schema, the definition establishes scope and the computation boundary adequately, and the parameters themselves are well described in the schema. The main residual gap is the absence of any indication of the response shape for a gate tool, which the agent would otherwise need to infer.

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 86%, so the schema already documents all seven parameters, including the regime enum and the individual boolean/percentage fields. The description adds no interpretation of the parameters (e.g., what counts as a qualifying AED threshold, how non_qualifying_pct interacts with non_qualifying_aed), so the baseline of 3 applies.

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 ('Check') and two precisely-cited regimes (UAE QFZP 0% de-minimis cliff under Decree-Law 47/2022, and GDPR Art. 3/30/35 triggers), which makes it clearly distinguishable from the sibling tools covering CBP drawback, CBAM/EUDR and 179D. It stops short of explicitly contrasting itself with any sibling, but the legal-citation specificity carries the differentiation.

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?

'Diagnostic gate only; no tax math' is a useful negative boundary that tells the agent this is a screening step rather than a computation. There is no positive when-to-use guidance, no statement of prerequisites, and no routing to an alternative when the answer is 'triggered' (e.g., a downstream computation tool).

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