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

Annotations already declare readOnlyHint=true and destructiveHint=false, so no contradiction exists. The description adds useful interpretation of results (gated/exclusive or operator-acquired) and the '100 percent of observed buybox days' condition, but it does not disclose operational details such as observation window, default limits, or what the returned records contain. With annotations covering 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?

The description is three sentences with no filler: the core definition is front-loaded, the interpretation is brief, and the usage triggers are compactly listed. Every sentence earns its place and helps an agent decide when to invoke the tool.

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 13-parameter tool with no output schema, the description covers the core concept and invocation conditions well, but it does not explain expected return shape, key default behaviors, or how optional filters relate to the single-operator condition. The annotations and partial schema descriptions provide some context, so it is adequate but not complete.

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 input schema describes 62% of the 13 parameters, and the description adds one central semantic idea—single-operator control over buybox days—that overlaps with the control-score filters. However, several parameters remain undocumented in both schema and description (limit, brand_contains, max_control_score, min_control_score, dominant_seller_contains), and the description does not compensate for that gap.

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 names a specific verb and resource ('Find brands') and adds a precise, measurable condition: a single operator controls 100% of observed buybox days. It also interprets what such brands mean ('gated/exclusive or operator-acquired'), which clearly separates this tool from more general brand competition tools. The trigger phrases reinforce the intended semantic scope.

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?

The description explicitly lists user phrasings that should route to this tool: 'brands with one seller', 'exclusive brands', 'single-seller brands', 'monopoly brands', and 'no competition'. It does not provide when-not-to-use guidance or name alternative sibling tools, so it falls just short of a 5.

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