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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so safety is covered. The description adds real behavioral value by naming the enriched sections returned (variant-level stock, estimated delivery date, offer_terms with free Singapore delivery/returns/authenticity), which tells the agent this is a heavy read rather than a thin lookup.

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 front-loaded sentence with the verb and resource leading; the long field enumeration earns its place because there is no output schema. Slightly dense 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?

With no output schema, the description carries the burden of describing return content and does so thoroughly, including variant and offer_terms detail. Minor gaps remain — no mention of error behavior for an unresolvable identifier or handling of unavailable products — but the essentials for correct invocation are present.

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 note that product accepts an ID, product slug, variant slug or SKU essentially restates the schema's own description, adding emphasis on identifier flexibility but no new syntax or format guidance; guest_token is left entirely to the schema.

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 ('Read one product in full') and then enumerates the payload — description, ingredients, usage, images, all variants with price/unit pricing/stock/delivery, plus offer_terms. This is unmistakably the single-product detail tool, distinct from search_products and the cart/checkout siblings.

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 'one product in full' framing makes the usage context clear: retrieve complete detail for a single already-identified product, rather than browse or search. It does not explicitly say 'use search_products first to find the ID' or state exclusions, 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.