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

Annotations already cover read-only and open-world semantics, but the description adds genuinely new behavior: best-effort results with possibly stale prices and an explicit sign-in/auth requirement, plus instructions to warn the user about price accuracy. It doesn't cover pagination or the meaning of limit, so it falls short of full disclosure.

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 short sentences, each load-bearing: what it returns, how results chain to the sibling, and the best-effort/auth caveats. Front-loaded with the core purpose and no filler.

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?

With no output schema, the description compensates by enumerating the result fields, and it adds the chaining path, accuracy caveat and auth requirement. An agent has everything needed to call it correctly and set user expectations.

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 75%, with sites and country well documented in the schema itself; the description adds no additional parameter meaning and says nothing about limit or result-count behavior. Baseline 3 is appropriate since the schema largely carries parameter semantics.

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 ('Find products for sale across online shops') and enumerates the returned fields, so an agent knows exactly what comes back. It also names the sibling get_product_offers and the chaining pattern, cleanly separating this search tool from the per-seller offer lookup.

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?

Explicitly tells the agent to pass product_id to get_product_offers to get every seller's price and shop link, which is real routing guidance against a sibling. It also flags operational context (best-effort, needs sign-in), though it never states when not to use this tool or which sibling handles non-product discovery.

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