compare_products

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

Rich behavioral detail is added beyond the annotations: 'one card request each,' the delivery-date request cost under with_delivery, express_delivery surcharge semantics, and explicit handling of failed SKUs 'with the reason.' The 'Live' qualifier aligns with openWorldHint. No contradiction with annotations exists.

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 opening sentence front-loads scope and request cost, followed by a well-organized per-SKU field list. The description is longer than strictly necessary, but every clause carries useful semantics, and the explicit cross-reference to get_product earns its place. Slight verbosity keeps it from a top score.

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?

Given an output schema is present, the description still supplements it with field semantics, failure behavior, and the line-rating caveat. It covers the cost model (one card request each, one small request per SKU), which is important operational context. No critical gaps remain for a safe read-only tool with annotations already declaring readOnlyHint and idempotentHint.

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 baseline is 3. The description reinforces that products are SKUs and that with_delivery maps to the delivery date under the cart button, but it does not add new meaning beyond the schema or materially resolve ambiguity. It is serviceable but not elevated.

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: 'Live side-by-side offers for up to 20 SKUs.' It clearly differentiates itself from get_product by noting that the rating shown is the card's line rating, not the SKU's own rating, and explicitly points to get_product for that. The function is unmistakably a multi-product comparison tool, distinct from search, detail, or review tools.

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 gives a clear when-to-use and when-not-to-use signal: if you need the SKU's own rating, 'use get_product for that.' It also frames the tool's domain as comparing up to 20 SKUs side-by-side, which is a clear context for when it is the right choice over search or get_reviews.

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