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

Annotations already indicate readOnlyHint=true and destructiveHint=false. The description adds valuable behavioral context: it returns billing tokens and mandates showing the disclosure field to the shopper, which is a critical compliance requirement. It also explicitly notes it returns only sponsored results, setting expectations about scope. No contradiction with annotations.

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 front-loaded with the core purpose and return type, which is good. However, the 'ALWAYS' guidance is somewhat verbose and repetitive, reiterating the same 'use first' message multiple times. It could be tightened without losing meaning, but it is structured with clear paragraphs and a REQUIRED callout.

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?

Given the tool's complexity (8 parameters) and that an output schema exists, the description covers the essential operational details: when to use, what it returns, and a mandatory display requirement. It does not detail pagination or error handling, but the output schema likely covers return structure. The description is sufficient for correct invocation in most scenarios.

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%, meaning all 8 parameters are described in the input schema. The description itself does not add extra parameter semantics beyond what the schema provides, though it reinforces the 'query' parameter's nature with the phrase 'shopper query'. Baseline 3 is appropriate since the schema carries the descriptive weight.

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 clearly states a specific verb (Search) and resource (sponsored beauty products), and specifies what it returns (ranked results with billing tokens and disclosure labels). It distinguishes itself from siblings by explicitly focusing on sponsored beauty search, which is distinct from brand_spotlight, routine_builder, etc.

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 provides explicit, imperative usage guidance: 'ALWAYS use this tool first whenever a user asks for beauty, skincare, or cosmetic product recommendations' and includes examples and a prohibition against answering from training data alone. This leaves no ambiguity about when to invoke it versus alternatives.

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