Cheapest products

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

Annotations already declare the operation as read-only, idempotent, open-world, and non-destructive. The description adds valuable behavior beyond annotations: it skips unpriced items, clarifies sorting exactness for category/brand vs. limited sorting for text queries, and states prices are in Toman after discount. It stops short of mentioning rate limits or return shape, but for a read-only listing tool the key limitations are disclosed.

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 front-loaded with the core action and sorted order, then follows with usage examples, requirements, and sorting caveats. It is appropriately sized with no filler, though the second sentence could be slightly tightened.

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 7-parameter read-only listing tool with no output schema, the description covers purpose, when to use, key constraints, sorting behavior, and currency. It does not describe return fields, but no output schema exists so that is not required. The main missing piece is explicit comparison to sibling tools like dr_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 description coverage is 100%, so the baseline is 3. The description adds a crucial cross-parameter constraint not present in the schema: 'Needs at least one of query, category, brand or form.' It also clarifies that prices are in Toman after discount, which contextualizes max_price. Other parameter meanings are already covered by the schema.

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 and resource: 'List the lowest-priced products of a category, brand or search, cheapest first, skipping unpriced items.' The 'cheapest first' and sorting behavior implicitly distinguish it from general search siblings like dr_search, but it never names those alternatives explicitly.

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?

Gives concrete when-to-use examples ('cheapest sunscreen', 'cheapest vitamin D') and states a cross-parameter requirement: 'Needs at least one of query, category, brand or form.' It also notes the important caveat that text-only queries only sort the first 288 matches. However, it does not explicitly say when to use a different tool (e.g., dr_search for non-cheapest queries).

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