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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds a freshness signal ('live') and enumerates the returned facets, but discloses no auth needs, rate limits, or edge-case behavior. With annotations carrying the safety profile, 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?

Two sentences, zero waste, and the core capability is front-loaded ahead of the sibling routing hint. Every clause earns its place.

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 single-param, read-only tool with annotations and an output schema, the description is nearly complete: it states scope, contents, and the sibling alternative. The minor ID-vs-URL wording inconsistency is the only gap.

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?

Single parameter with 100% schema coverage, so baseline is 3. The description says 'product URL or product ID' while the schema only documents 'Balenciaga product URL or Product-Variation URL' — a mild mismatch that neither clarifies nor fully aligns with the schema, so no credit above baseline.

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 (Fetch) and resource (Balenciaga's live variation matrix), enumerates the returned dimensions (colors, sizes, sellability, care text, related IDs), and explicitly contrasts with the sibling balenciaga_product. An agent can distinguish it from balenciaga_product 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?

Names the alternative balenciaga_product and the condition that selects it ('for the product's core detail'), implying this tool is for the variation matrix. It gives clear routing context but does not state when-not to use this tool or any prerequisite.

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