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

Annotations already cover read-only and open-world behavior, and the description adds genuinely new operational context: the x402 payment requirement, cost per successful call, and that failed calls are not charged. That payment/auth disclosure is the critical behavioral fact here, though it says nothing about rate limits or response shape (output schema handles the latter).

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 the core resource and scope, followed by a compact field list and the pricing caveat. Slightly dense and the field enumeration partly duplicates the output schema, but no sentence is wasted.

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 with full schema coverage and an output schema, the description supplies everything an agent needs: data source, geographic scope, exclusions, filterable categories, and the payment model. Nothing material is missing before invocation.

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%, so all five parameters are already documented with examples. The description adds only indirect meaning by explaining what the category prefixes (POA/PNAO/live animals, HC/NHC, temperature specs) represent; it doesn't clarify the type/limit/code/name filters beyond what the schema states. Baseline 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 resource (UK border control posts for live animals, POAO and high-risk food/feed) and enumerates the returned fields, so an agent knows exactly what it retrieves. The 'UK only (GB and Northern Ireland), not the EU list' clause cleanly separates it from sibling customs/tariff tools such as logistics_uk_trade_tariff or logistics_phytosanitary_cert_req.

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 gives clear applicability context ('UK only, not the EU list') and states the data source (GOV.UK/Defra/APHA). It does not explicitly name a sibling alternative or say when a different tool should be preferred, so it stops short of full routing guidance.

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