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

Annotations already mark the tool read-only and idempotent; the description adds meaningful behavioral context about normalized price-per-unit comparison and recursive category/subcategory scope. It does not cover edge cases or return shape, but those are less critical with readOnly/idempotent hints present.

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?

Three tight sentences: the core behavior, the primary use case, and the prerequisite. Nothing is wasted and the key scoping detail is front-loaded.

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 simple read-only list tool with a fully described input schema, the description is complete enough: it identifies the query intent, the search scope, and how to obtain the required category_slug. No output schema exists, but the tool's output shape is inferable for this kind of listing operation.

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 schema already documents limit, market, category_slug, and in_stock_only. The description's mention of valid slugs and subcategory inclusion reinforces category_slug semantics but does not add meaning beyond it, matching the baseline.

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 exactly what it does: finds cheapest supplements by normalized price-per-unit within a category and its subcategories. This verb+resource+scoping is precise and distinguishes it from siblings like get_product and search_products.

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?

Clear context is provided: it is the primary tool for cheapest-X questions, and the prerequisite call to list_categories is stated. It does not explicitly describe when to prefer search_products or when not to use this tool, so it stops short of a 5.

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