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

Annotations already declare this as a read-only, idempotent, non-destructive, closed-world lookup. The description adds useful behavioral detail beyond annotations, specifically that quantity causes package-size rounding and a line-total calculation, though it does not describe error behavior for invalid or missing identifiers.

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?

The description is compact and front-loaded with the core lookup behavior, then adds the quantity effect. It is dense but efficient, with no obvious filler, though the phrase 'minimum order / package rules' is slightly compressed.

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 tool has three parameters, no output schema, and annotations that cover safety. The description lists returned data and quantity behavior, which is helpful, but it omits the important precondition that at least one of product_id or EAN should be supplied, and gives no error semantics.

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 carry parameter meaning. It explains that product_id and EAN are alternative lookup keys and that quantity affects orderable quantity and line total, but it does not clarify whether at least one identifier is required, what happens if both are supplied, or EAN format expectations.

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 states a specific verb/resource: retrieve product detail by product_id or EAN, and lists the fields returned. It is clear what the tool does, though it does not explicitly distinguish itself from search_products or check_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?

Usage is implied: use this for a known product_id or EAN, and optionally pass quantity for orderable quantity and line total. However, there is no explicit when-to-use guidance versus search_products or check_availability, and no exclusion rules.

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