compare_products

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is covered. The description adds valuable behavioral context: it reveals that the tool computes the cheapest delivery with its date, price after coupons, and price range over variants—behaviors not inferable from the schema alone. No contradiction with annotations.

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 a single, well-structured sentence that front-loads the primary purpose and output attributes, followed by a concise exclusion note. Every phrase contributes value; no redundancy or fluff. It is efficient and easy to parse.

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?

The tool is moderately complex (comparison with up to 10 items, multiple output dimensions, city-based pricing). The description covers the key output elements and explicitly notes what is NOT included (seller details). Since an output schema exists, return format is not required. It does not mention error handling or edge cases, but the essential information for calling the tool correctly is present.

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% for both parameters (city and items), so the baseline is 3. The description adds meaning by clarifying that the comparison uses the 'pre-selected variant' and details coupon pricing and delivery selection, which enriches understanding of how the 'items' parameter is interpreted. This goes beyond the schema's generic 'ids or URLs' description.

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 clearly states the tool's function: comparing up to 10 products side-by-side, listing specific attributes (price, price range, coupon price, delivery, rating, etc.). It also explicitly contrasts with get_product for seller details, distinguishing it from a sibling. The verb 'compare' and resource 'products' are precise and unambiguous.

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 description provides an explicit exclusion: seller details and characteristics are only in get_product, so an agent knows not to use this tool for that. It implicitly indicates usage for multi-product comparison via 'up to 10 items' and the side-by-side framing, but does not explicitly state when to prefer it over search_products or get_reviews. Clear enough for typical cases.

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