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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context by disclosing the exact data sources consulted (BPR, Article 95, BPC opinions, HSE/GB, SIMMBAD, ANSES, BAuA, EPA List N, Health Canada), which tells the agent what answers are grounded in.

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-loads the core purpose, then organizes the source list into labeled groups (EU / National / US / Canada), which makes the length scannable. The jurisdiction-by-jurisdiction register enumeration is dense and borders on over-long, but each group carries real routing information.

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 an output schema present, return values needn't be described, and the description fully covers scope, supported jurisdictions, input convention, and the exclusion boundary. For a 6-param, zero-required, multi-jurisdiction lookup tool, nothing an agent needs to call it correctly 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 description coverage is 83%, so the schema does most of the work (baseline 3). The description adds meaning by framing the PT1–PT22 product-type range, explaining that target_pathogen drives US disinfectant lists, and tying include_suppliers to the Article 95 list, which goes beyond the field-level descriptions.

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?

Opens with a specific verb+resource ('Checks whether a biocidal active substance is approved') and enumerates the exact facets covered (active substance approval, Article 95 list, product authorization, EPA disinfectant lists). It explicitly carves out the sibling regaffairs_check_pesticide_approval_and_mrl, so an agent can distinguish it without opening either 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?

States the input convention ('Give an active substance or a product name') and an explicit exclusion with the alternative tool named for plant protection/MRLs. It lacks guidance on choosing among the sibling check_* tools (e.g. check_chemical_substance) or when to set jurisdictions, 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.