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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), but the description adds substantial context beyond them: the $0.002 USDC per-successful-call x402 pricing on Base/Solana/Arc, and that failed calls are not charged — a genuinely important consideration before invoking. It also discloses the 'first page only' result ceiling and the data gaps (no ratings, counts, or prices). It does not explain wallet setup or pagination beyond the page limit.

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 first two sentences are front-loaded and information-dense, but the closing sentence is boilerplate cross-sell for an unrelated restaurant-supply tool that does not help an agent decide anything. The payment clause is worth its length; the sibling reference is not.

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?

An output schema exists, so return structure need not be explained, and the description still names the returned fields plus the known data gaps. Cost, charging conditions, and the first-page limitation round out what an agent needs to call it correctly. Only the absence of any usage/pagination guidance and a relevant alternative keeps it from a 5.

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%, and both parameters carry their own constraints (q length/character set, limit range 1–20 with default 5), so the schema does the heavy lifting. The description adds no syntax or behavioral detail about the parameters themselves — 'first page only' loosely implies the practical cap on limit but does not state the relationship. Baseline 3 applies.

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 names the resource (Chrome Web Store search results) and precisely enumerates what it returns: extension name, id, and detail-page link. It also delimits scope (public results page, first page only) and states negatively what is absent (ratings, user counts, prices), which helps an agent tell it apart from the many shopping/price siblings. It stops short of an explicit verb or a direct contrast with any specific sibling.

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?

There is no guidance on when to reach for this tool versus the closest alternatives among the ~60 ecommerce siblings, nor any prerequisite or exclusion beyond 'first page only'. The single routing hint points to ecommerce_restaurant_depot_sysco_us_foods_chef_store, which is a restaurant-supply price scraper — a mismatched and unhelpful alternative for an extension lookup task.

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