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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds genuinely useful behavioral context beyond annotations: data availability is gated ('after the gate also...'), which tells the agent that the response is richer once a gate decision exists. No contradiction with annotations.

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?

A single dense sentence front-loads the core operation ('one product by GTIN') followed by a concise colon-separated field list. Every phrase earns its place; 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?

The description is adequate for a simple GTIN lookup and the output schema presumably documents return values, but the unexplained 'gate' concept and silent optional parameters (market, decision_id) leave an agent uncertain about precondition requirements and richer invocations.

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 0%, so the description must explain parameters. It covers gtin ('by GTIN') and alludes to market as a resolved field, but it never explains the market input parameter or the decision_id parameter, which are significant gaps for an agent trying to call the tool correctly.

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?

Description states a specific operation: retrieve one product by GTIN with fully resolved data, and enumerates the data categories (taxonomy, variant/form, brand, market, claim status, availability, etc.). This clearly differentiates it from sibling tools like search_cleared_items, compare_items, and get_availability.

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?

The phrase 'One product by GTIN, fully resolved' gives clear context for when to invoke it — a single-product canonical lookup by GTIN — with no exclusions. It does not name sibling alternatives or when-not-to-use conditions, so it stops short of a 5.

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