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

Beyond the readOnly, idempotent, and non-destructive annotations, the description discloses meaningful behavior: results are best-deals-first, capped at 12, and limited to genuine reductions where the cut is recent, the price is the market's lowest, and the normal price comes from the product's own history. That is useful operational context, though it does not discuss pagination or error behavior.

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 compact and front-loads the main purpose, filtering options, and result limit. It is slightly less concise than ideal because it lists output fields even though an output schema exists, but there is no filler or repetition.

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?

For a read-only, closed-world tool with full schema coverage and an output schema, the description supplies everything needed to call it correctly: market behavior, optional filters, reduction criteria, ordering, and result cap. The remaining details are appropriately left to the schema and annotations.

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%, so the schema already explains the market enum, the category slug, and that max_price is in major units. The description references the category slug and market currency but adds no syntax or format details beyond what the schema already provides, making the baseline score appropriate.

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 states a specific verb and resource: it returns products whose prices have recently fallen in a market, with deals sorted best first and a maximum of 12. This is clearly narrower than generic product search or price comparison, so an agent can identify the tool without opening the schema.

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?

It explains that results can be narrowed by category slug and max price, and it defines what counts as a genuine reduction. However, it never names an alternative such as compare_prices or search_products, nor does it state when not to use this tool, leaving the selection guidance only implied.

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