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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so safety is covered. The description adds real value beyond them by disclosing what a call returns (plain-language meaning, example perfumes, related terms) and the language behavior of the linked guide versus the answer body, though it says nothing about rate limits or fallback behavior for unknown terms.

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 trigger condition, then the return contract, then the exclusions – a sensible order with no filler sentences. The long inline term list is somewhat heavy but it doubles as disambiguation evidence, so it earns its space; only the sheer length keeps it from a 5.

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 detail is not strictly required, yet the description still summarizes the response shape. Combined with the 100%-covered input schema and the read-only annotations, an agent has everything needed to select and invoke this tool correctly.

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 coverage is 100%, so the baseline is 3, but the description goes slightly beyond the schema by enumerating representative 'term' values ('sillage', 'drydown', 'chypre', 'EDP vs EDT'), which tells the agent how to phrase multi-word or acronym-style terms. The lang guidance largely mirrors the schema text, so the gain is modest rather than substantial.

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 and resource ('Explain a perfumery term') and enumerates the exact term space it covers (sillage, drydown, chypre, EDP vs EDT, etc.), so an agent knows precisely what class of query belongs here. It also names the siblings it is not (note-portrait, perfume-portrait), making it distinguishable without opening any 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?

Opens with an explicit trigger ('Use this when the user asks what a perfume or fragrance term means') and closes with explicit exclusions routing to alternatives ('Don't use for a specific note (use note-portrait) or a specific perfume (perfume-portrait)'). Both the when and the when-not plus the named fallbacks are present.

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