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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description usefully adds that the assessment is benchmarked against fixed published standards, implying deterministic rule-based evaluation rather than open-ended judgement. It does not disclose what the check produces (pass/fail per criterion, gaps list, severity) which matters because there is no output schema.

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 dense sentences with no filler, front-loaded with the tool's purpose and followed by the accepted inputs. The regulatory citations are long but each carries real selection value; only the input list feels slightly tacked on rather than integrated.

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 nine-parameter domain tool with no output schema and thin schema descriptions, the definition covers the regulatory scope and the main numeric inputs but leaves the preset mechanism, shape semantics, and the shape of the returned assessment unexplained. An agent could invoke it, but not predict or interpret the result confidently.

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 only 33%, so the description must compensate, and it partly does: it clarifies that d10/d50/d90 are particle size in nm, that ssa is BET surface area, and that sdsText is optional. It adds nothing about the 'preset' enum (seven material presets that presumably fill defaults), 'shape', or how materialName drives the lookup, leaving several parameters undocumented in both places.

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 a precisely scoped resource: a nanomaterial against three named regimes (2022/C 229/01 EU definition, REACH Annex II / Regulation 2020/878 SDS nanoform requirements, ISO/TR 13014 characterisation coverage). That is far more specific than the sibling '*_check' tools, although it never explicitly distinguishes itself from regulatory neighbours like cra_disclosure_scan or battery_passport_check.

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?

There is no when-to-use / when-not-to-use guidance, no statement of prerequisites (e.g. that materialName alone yields a partial result, or that SDS text is needed for the SDS section to be meaningful), and no mention of alternatives or downstream steps. Only the closing clause about accepted inputs implies the intended calling context.

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