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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine behavioral context beyond that: it itemises the rich payload (variant matrix, per-variant pricing/stock/images) and, crucially, documents that sku accepts three distinct identifier formats, which tells the agent it does not need to normalise input first.

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 core purpose, then the field inventory, then the sku-format caveat. Every sentence carries information, though the long field enumeration is partly redundant with the output schema and could be trimmed. Two sentences, no filler.

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 values need no explanation, yet the description still gives an agent enough to call correctly: required sku with all three accepted formats, optional locale implied by market naming, and confirmation this is a single-item detail fetch. Nothing needed for correct invocation 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 100%, so both sku and locale are already documented in the schema. The description restates the three accepted sku forms almost verbatim and says nothing about locale, so it adds essentially no meaning beyond the structured fields. Baseline 3 applies.

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+resource ('One Hermes product's full detail') and enumerates exactly what that detail contains (title, colour matrix, per-variant sku/price/stock). The singular framing and the reference to 'the URL identifier hermes_products returns' cleanly separate it from the plural hermes_products listing sibling.

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?

Usage is only implied: by noting that hermes_products returns the URL identifier, the description hints that this tool is the follow-up detail call after a listing or search. There is no explicit when-to-use statement and no named alternative (hermes_products, hermes_search, hermes_suggest) with the condition that selects it.

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