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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds value beyond that by naming the returned profile fields and, more importantly, disclosing that the single input accepts two different identifier forms — a behavioral nuance the annotations do not convey. No auth, rate-limit, or not-found behavior is mentioned, which keeps it out of 5 territory.

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 short sentences: what it returns, what it accepts, and which sibling to use instead. The most decision-relevant information (the return shape and the alternative tool) is front-loaded with no filler.

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 one required parameter, full schema coverage, a present output schema, and annotations carrying the safety profile, the description covers everything an agent needs to invoke it. Only edge behavior (unknown shop, id-vs-name precedence) is unstated, which is a minor gap given the output schema handles the return contract.

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 schema's own text ('Numeric Etsy shop id or shop name') is essentially identical to the description's sentence. The description therefore adds no syntax, format, or precedence detail beyond what the schema already provides — the baseline 3 for a fully documented single parameter.

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 (returns an Etsy shop profile) and enumerates the payload (seller, headline, rating, sold count), which lets an agent distinguish it from etsy_shop_listings, etsy_shop_reviews, and etsy_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?

Explicitly routes the agent to etsy_shop_search when it wants to find shops rather than fetch one, and the 'accepts a numeric shop id or a shop name' line clarifies the lookup precondition. It stops short of stating the inverse rule (use this tool only when you already have an id or exact name), so it is clear context rather than a full when/when-not pair.

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