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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered. The description adds real scope context — the exact standard lists and labelling regulations consulted — which is not derivable from the annotations. No auth or rate-limit detail, but that is minor here.

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?

Purpose, scope and the sibling exclusion are front-loaded; the long enumerations of lists and labelling rules each earn their place by anchoring schema enum values. The mid-sentence 'Give substances or a topic' is slightly awkwardly placed but not wasteful.

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 need not be described. The description covers the substance-list scope, the labelling scope, the input convention and the sibling boundary — sufficient for a 5-parameter, 0-required tool.

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 80%, so baseline is 3. The description exceeds that by mapping enum values to their real-world meaning (zdhc_mrsl = ZDHC MRSL, oeko_tex_100 = Standard 100 class limits, reach_annex_xvii = Annex XVII textile entries) and clarifying the substances-vs-topic interplay, which the enum labels alone do not convey.

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 (checks) and resource (restricted substances and labelling for textiles/clothing/footwear/leather) and enumerates exactly which regimes are covered. It explicitly distinguishes itself from sibling `regaffairs_check_chemical_substance`, so an agent can route 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?

Gives an input convention ('Give substances or a topic') and an explicit exclusion with the named alternative ('Not intended for general chemical status outside textiles; regaffairs_check_chemical_substance covers that'). It lacks a positive when-to-use example, but the routing guidance is clear.

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