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

Annotations cover the safety profile (readOnlyHint, openWorldHint), and the description adds genuinely non-obvious context: a 3-credit cost and the shape of each returned item. That cost disclosure is exactly the kind of operational detail annotations cannot carry. It omits caching behavior and pagination, so not a 5.

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, purpose first, then result shape, then cost — the highest-value fact (credit cost) is not buried. No filler or restatement of the title.

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 does carry the return-value burden and does so in one clause. But for a 5-parameter tool at 40% schema coverage, it should explain pagination and the tld/country_code relationship; that gap leaves it only minimally complete.

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 only 40% — tld and query are documented in the schema, while page, country_code, and cache_max_age have no description anywhere. The description does not compensate at all: it never mentions the page parameter, the marketplace selector, or the cache lifetime, leaving three of five parameters unexplained.

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 states a specific verb and resource ('Search Walmart') and characterizes the result set (position, price, rating, availability per item), so an agent can tell it apart from walmart_product or walmart_category. It stops short of explicitly naming those siblings, which keeps it from a 5.

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?

It says the results are 'public,' implying unauthenticated listing retrieval, but gives no when-to-use guidance, no exclusions, and never mentions that walmart_product or walmart_reviews exist for follow-up detail. An agent must infer the routing decision from the tool name alone.

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