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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real behavioral context: it enumerates the returned content (per-SKU price/sale/availability, conditional reviews 'when the product has any') and discloses error behavior for an unrecognized product_id. No rate-limit or pagination info, but the bar is lower with annotations present.

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?

Front-loaded with the return content, then the parameter source, then the error behavior. Dense but each clause earns its place; the one-sentence run-on could be split for readability, but nothing is redundant.

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?

An output schema exists so return values need not be explained, yet the description still summarizes them usefully. Combined with the input-source guidance and the not-found error disclosure, an agent has everything required to call this correctly.

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%, so the description must carry the parameter burden, and it does: it explains the origin of product_id (a lululemon_category id field or a URL trailing segment) and clarifies the slug is not needed. It does not specify the id's format (numeric vs alphanumeric), which is the only remaining gap.

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+resource (one product's full detail) and enumerates exactly what that detail contains (per-SKU price, sale status, live availability, rating, reviews). It also explicitly distinguishes itself from lululemon_category, so an agent can route without opening either 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?

Explicitly tells the agent when to use it (SKU-level detail and reviews 'not available from lululemon_category') and where the required input comes from (a lululemon_category result's id field or a URL's trailing path segment). The slug caveat and the alternative-naming leave nothing to inference.

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