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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safe, non-external-fetch read profile is covered. The description adds what the payload contains (specs, price, stock, delivery, returns, links), but says nothing about behavior on a missing/unknown SKU. With annotations carrying the safety burden, a 3 is appropriate.

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 sentence, front-loaded with the core purpose and then the return contents and an inline example. No filler and nothing an agent must hunt for.

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?

For a simple one-param read tool with no output schema, listing the returned facts (specs, price, stock, delivery, returns, links) largely compensates for the absent output schema. The only real gap is error/not-found behavior, which is minor for this tool.

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 0% and there is one required param, so the description must carry the semantics. It supplies both the meaning (SKU) and a concrete format example (ST-54137787), which meaningfully exceeds the bare 'string' type in the schema. It could go further on case sensitivity or format rules.

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 with scope ('one product by SKU') and enumerates the returned fields, which distinguishes it implicitly from the plural search_products sibling. It stops short of naming that sibling explicitly, so it is clear but not maximally differentiated.

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 by 'one product by SKU' versus a search tool, but there is no explicit when-to-use/when-not statement or named alternative. An agent can infer the keying requirement from the required sku param, but nothing in the text routes it against create_checkout_link, get_policies, or search_products.

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