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

readOnlyHint=true already establishes this as a safe read. The description adds useful content-level context by declaring what is returned and explicitly what is excluded (cost/trade pricing), which prevents wrong expectations. It stops short of covering error behavior for invalid SKUs/URLs or any lookup constraints.

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?

Two tight sentences, front-loaded with the returned fields and closed by the exclusion. Every clause adds information; nothing is repeated from the name, title, or schema.

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 field enumeration does real work in describing the return payload, which is appropriate for a read-only tool. However, it omits any explanation of the identifier input or routing relative to the five sibling tools, leaving gaps an agent would need to resolve.

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 the single parameter product_url_or_sku carries no description, so the description must compensate and does not — it never mentions the input. The parameter name is largely self-describing (URL or SKU) and maxLength 80 hints at SKU-oriented input, keeping this at baseline rather than below.

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 names a specific resource (product) and enumerates the exact fields returned (title, brand, part number, price, availability, key facts, exclusions), so an agent knows precisely what this retrieves. It does not explicitly contrast itself with siblings like search_parts or check_part_fit, but the resource is unambiguous without opening the schema.

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?

There is no guidance on when to use this versus search_parts or find_parts_for_vehicle, nor any stated prerequisites. The clause 'No cost or trade pricing' scopes the returned content but is not usage direction, so the agent must infer that this is a single-item lookup by identifier.

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