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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety and open-world profile. The description adds the default scoping values (num=30, country=us, lang=en), which is mild extra context, but it discloses nothing about rate limits, result truncation, or how defaults affect results. With annotations carrying the safety burden, a 3 is appropriate.

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?

It is front-loaded with the return shape, which is good, but it then repeats parameter definitions already present in the schema ('Country: Two-letter storefront country code, ISO-2, default us'), and the final suggest sentence is slightly malformed ('retrieve suggest Chrome Web Store search terms'). Not wasteful enough to drop below 3, but not tight either.

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 values need not be described, and annotations already carry the safety profile. The description covers the required keyword and all defaults plus an alternative tool, leaving only minor gaps like the maximum value or behavior of `num`, which an agent can live without.

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 all four parameters are already documented. The description largely restates the schema (Term, Country, and their defaults are near-identical), adding no syntax or constraint detail beyond what the schema provides. Baseline 3 holds when the schema does the heavy lifting.

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 ('Returns Chrome Web Store search result cards for a keyword') and even enumerates the returned fields (id, name, rating, user count, publisher, detail URL), so an agent knows exactly what it produces. It also names the sibling chromewebstore_suggest, distinguishing this tool from it.

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 gives a clear context of use for a keyword search and explicitly routes the agent to chromewebstore_suggest for suggest/autocomplete terms. It stops short of precise when-not conditions or limits on the search itself, but the alternative is named and its purpose inferred.

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