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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful behavior beyond that: it discloses the shape of each shelf (normalized products with price, stock, image) and, importantly, that a product with no shelves returns an empty list rather than an error.

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?

Three tight sentences with zero waste, front-loaded with what the tool returns and closing with the one non-obvious edge case. Nothing needs to be re-read or inferred from padding.

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 an output schema present the description needn't detail return structure, yet it still summarizes shelf contents and the empty-list behavior. Combined with the annotations, an agent has everything needed 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 description coverage is 100% and the sku field already states 'in any of the forms hermes_product accepts', so the description's 'takes the same sku forms as hermes_product' largely repeats structured data. Baseline 3 is appropriate; locale is not elaborated on beyond 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 the exact resource (the two cross-sell shelves on a Hermes product page) and names both shelf types with their semantics. An agent can distinguish this from hermes_product (single product detail) and hermes_products (listing) without opening any 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?

It implies the precondition that you already have a sku and cross-references hermes_product for sku forms, which hints at the workflow, but it never states when to call this versus siblings or what the alternatives are. Usage is inferable rather than explicit.

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