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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description adds one genuinely new behavioral fact beyond the annotations: no payment or provider call is incurred. It still says nothing about rate limits, latency, or what a discovery call actually produces.

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?

A single short sentence, front-loaded with the read-only qualifier. It is efficient and wastes no words, though for a tool with no parameters and no output schema it is arguably too terse to be fully self-sufficient.

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 zero-parameter discovery tool this covers the safety and cost profile, but it leaves open what discovery returns and how the result relates to the invoke_/result_ siblings. With no output schema, the description should carry more of that burden than it does.

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?

The tool takes zero parameters and the schema is empty, so there is no parameter semantics to convey; the baseline for a parameterless tool is 4. The description neither misleads nor needs to compensate for anything here.

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?

The description says it is a 'read-only discovery' for product_keyword_search_v0, which is close to restating the name rather than stating a concrete verb+resource outcome. The one piece of real information, 'no payment or provider call', does separate it from the invoke_product_keyword_search_v0 sibling. Purpose is implied rather than explained.

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?

There is no explicit when-to-use guidance. The reader can infer that this is the free/inspection counterpart to invoke_product_keyword_search_v0, but the description never says to call this first, what it returns, or when the invoke_ variant is required instead.

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