compare_products

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

There are no annotations, so the description carries the full burden. It discloses one concrete behavioral trait (results sorted by lowest price) and implies a read-only operation via "Shows", but it does not mention authentication requirements, failure behavior, data freshness, or any side effects. This is some value added, but not comprehensive.

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 three short sentences with no fluff. It leads with the action and resource, then lists outputs and sort order, making it easy to scan and 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?

There is no output schema, but the description enumerates the main result fields (pricing, availability, variants, options) and the ordering. The input side is fully covered by the schema. A full return shape is not specified, but the gaps are minor given the tool's simple comparison nature.

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?

The input schema has 100% description coverage for the products array, productId, and merchantUrl, so the schema fully documents the parameters. The description adds no parameter-level semantics, keeping this at the baseline score.

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?

"Compare multiple products side-by-side across merchants" uses a specific verb and resource, and clearly separates it from siblings like get_product and search_products. It also names the key result aspects (pricing, availability, variants, options) and the sort order, making its function 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 implies when to use the tool (when a side-by-side comparison across merchants is needed), but it does not explicitly state when-not-to-use it or contrast it with alternative tools. An agent has to infer the appropriate context.

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