Compare products across stores

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint. The description adds valuable behavioral context: it uses 1 extraction per URL and requires a paid CartScout plan (PRO or higher). This goes beyond the annotations and helps the agent understand cost and access constraints.

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?

Two sentences, front-loaded with the core purpose and comparison dimensions, followed by cost/plan constraints. Every sentence earns its place; no fluff.

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 description covers what the tool does, the input constraints, the cost model, and the plan requirement. The output schema exists, so return values don't need to be described. Minor gap: it doesn't mention what happens if URLs are invalid or not product pages, but that's not essential for an agent to invoke it correctly.

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 schema already documents the 'urls' parameter. The description adds the 2-10 range and the example 'one item at several stores', which reinforces but doesn't significantly extend the schema. Baseline 3 is appropriate.

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 2-10 product pages side by side, and lists the specific comparison dimensions (cheapest, cheapest in stock, best rated, biggest discount, price spread, GTIN matching). This distinguishes it from siblings like get_product or get_price_history.

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 specifies the input range (2-10 URLs) and the use case (comparing the same product across stores). It doesn't explicitly say when NOT to use it or name alternatives, but the context signals and sibling list make the use case clear.

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