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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real behavioral context beyond that: the full scope of what is covered, and that omitting the term returns the entire term list rather than erroring. It does not discuss paging or result shape, but the output schema carries that.

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 purpose, then coverage, then trigger examples, then the exclusion. The parenthetical term inventory is long but earns its place by telling the agent exactly which lookups will succeed rather than fail. Slightly dense for a single sentence chain, but no filler sentences.

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?

An output schema exists, so return-value explanation is unnecessary, and the schema documents all four parameters. The description supplies everything else an agent needs: coverage boundaries, empty-term behavior, and the sibling to use for similar-but-out-of-scope requests.

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 the baseline is 3. The description's parameter-relevant statements ('leave term empty to list everything covered') largely duplicate the schema's 'Omit to list all terms', and its term examples mirror the schema's examples, adding little beyond the structured fields.

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 concrete verb (explain) and an enumerated resource scope: concentrations, sillage, projection, longevity, dry down, accord, note structure, flanker, maceration, layering, niche vs designer, plus 23 families. It explicitly distinguishes itself from the sibling explain_note, 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 literal phrasing for triggering queries ('what is the difference between EDT and EDP', 'what is a chypre', 'what does sillage mean'), states the empty-term behavior for browsing the full catalog, and names the exclusion case with the correct alternative (individual notes -> explain_note).

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