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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds useful behavioral context by specifying what each returned comparable includes (brand, title, price/price range, fulfillment with FBA/FBM/AMZ and percentage splits). 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?

Three tight sentences: purpose, usage triggers, and output contents. Every sentence earns its place, and the main purpose is front-loaded.

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 19 parameters, low schema coverage, and no output schema, the description is too thin to be fully actionable. It describes the output shape at a high level but leaves out marketplace semantics, default limits, filtering behavior, and return structure, so an agent would still face significant ambiguity when invoking the tool.

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 only 32%, leaving many parameters undocumented. The description names broad filter dimensions (brand, price band, seller count) that map to some parameters, but it does not explain key parameters like limit, marketplace_id, min/max_days_observed, fulfillment percentages, or the various 'contains' filters, so it does not sufficiently compensate for the schema 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?

The description opens with a specific verb and resource: 'Find ASINs similar to a given ASIN', and further specifies the similarity dimensions (brand, price band, seller count). It also clarifies this is an ASIN-level lookalike tool, distinguishing it from brand-level siblings like brand_similar.

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 user-phrase triggers ('ASINs like this one', 'similar products', 'comparable ASINs') and one concrete example. It clearly states when to use the tool, though it does not explicitly mention when not to use it or name alternative sibling tools.

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