asin_comparables

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

Annotations already provide readOnlyHint=true, and the description adds detail about what each comparable includes: 'product brand, title, price (or price range) and fulfillment (FBA/FBM/AMZ + amz/fba pct).' This gives valuable output context beyond the readonly fact.

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 concise—two sentences—with the first sentence stating the purpose and criteria, and the second listing output fields. It is front-loaded and contains no unnecessary words.

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 and no output schema, the description gives a basic overview of the tool's functionality and output, but does not explain how parameters interact (e.g., whether filters are combined, how limit works, or how marketplace_id affects results). It is adequate but not comprehensive.

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 only 32%, meaning most parameters lack descriptions. The description mentions filtering by 'brand, price band, and seller count' which maps to a few parameters, but does not explain the many other optional filters like limit, min_days_observed, or buybox_seller_contains. The description fails to compensate for the low schema coverage.

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 the tool's purpose: 'Find ASINs similar to a given ASIN by brand, price band, and seller count.' It lists specific user queries that trigger its use, distinguishing it from sibling tools like asin_buybox_history or asin_profit_calc.

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 tells when to use this tool: 'Use when the user asks ASINs like this one, similar products, comparable ASINs, what else is like B08N5WRWNW, or any ASIN-level lookalike question.' It provides clear context, though it doesn't discuss alternatives or when not to use it.

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