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

Annotations already establish readOnly, idempotent, non-destructive, non-open-world behavior, so the description only needs to add what annotations cannot. It does: results are ordered cheapest first, each figure carries its source and date, and supplying sell_price plus channel triggers per-supplier profit after fees. Missing details like caching or rate limits keep it from a 5.

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?

Two sentences, front-loaded with the returned data and followed by the input-triggered behavior. The first sentence is dense with enumerations but each item is informative; there is little wasted text.

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 no output schema, the description carries the full burden of describing returns, and it does so thoroughly: the fields returned, their provenance (source and date), the ordering, the summary sentence, and the conditional profit output. Combined with a 100%-covered input schema, an agent has everything needed to call this correctly.

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 100%, so the baseline is 3. The description earns above that by explaining the causal relationship between parameters and output: sell_price yields profit, an optional sales channel selects which fees are subtracted, and the product argument is what scopes the whole lookup. It does not mention buyer_pays_shipping, which the schema alone must carry.

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 resource and output set: every supplier's US cost for one print-on-demand product, broken into base price, first-item shipping, total, source, date, sort order, plus a one-sentence cheapest-supplier answer. That is far more precise than the title alone. It never differentiates itself from the sibling compare_suppliers, so it falls short of a 5.

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 second sentence gives conditional input guidance ('Give sell_price ... to get each supplier's profit after fees'), which implies when the profit mode activates. However there is no explicit when-to-use versus compare_suppliers or find_products, and no exclusions or prerequisites are stated.

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