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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds genuine behavioral value beyond that: the output mode changes depending on whether a target is supplied (listing categories/products vs returning visibility, share of shelf, and shelf holder). It stops short of describing pagination or return shape.

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 short sentences, front-loaded with the domain concept before the mode behavior. No wasted words, though the terse phrasing makes the target/target_kind relationship slightly ambiguous.

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 description does a fair job explaining the dual output modes. But for a 3-param tool with 0% schema coverage, it omits the required project_id and the distinction between target_id and target_kind, which an agent needs to invoke 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 load. It conveys the central role of 'target' (list mode vs detail mode) which maps to target_id, and 'categories and products' echoes the target_kind enum. But it never mentions project_id (the required param) or names target_id/target_kind explicitly, leaving meaningful gaps.

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 resource ('product recommendations in AI answers') with the read semantics carried by the name/title. It distinguishes itself reasonably from the many read_visibility_* siblings by focusing on product recommendations and shelf share. It doesn't explicitly name a sibling it is not, so it falls short of a 5.

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 explains the two operating modes via the presence or absence of a target ('without a target... with one...'), which is useful invocation context. However, it gives no when-to-use vs alternatives guidance and never names which sibling to prefer for related questions.

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