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

Annotations already establish read-only and the title covers scope, but the description adds substantive context: prices are US eBay Buy It Now asking prices (item + shipping, USD), explicitly not sold prices, and staples return cheapest per-unit across Amazon and eBay. That 'asking not sold' caveat is exactly the kind of caveat an agent would otherwise get wrong.

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?

One dense but front-loaded passage: coverage and return semantics lead, caveats follow. No filler sentences, though the category enumeration is long and could be trimmed without losing much.

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 return-value burden and does so (lowest/median asking price, currency, unit-price mode, product link). The only real gap is 'limit' behavior and result count/pagination, which is minor for a simple two-parameter search.

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 50%: 'query' is documented in the schema and the category list reinforces what kinds of strings work. The 'limit' parameter is undocumented in both schema and description, so the description does not compensate for the coverage gap; baseline 3.

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?

States a specific verb+resource ('Find current prices for a product') and enumerates covered categories, so an agent knows this is broad product price lookup. It does not explicitly name how it differs from siblings like get_price or price_per_unit, leaving that inference to the agent.

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?

Usage is only implied: you call it when you have a product query. There is no explicit 'use this instead of get_price when...' or exclusion guidance among the six siblings, which matters given the overlapping price-oriented siblings.

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