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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds real behavioral context beyond that: default storefront/language values (country=us, lang=en) and the fact that output is normalized, which shapes what the agent receives.

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?

Purpose and routing are front-loaded, followed by a compact default/param recap. The long field enumeration is somewhat list-heavy but earns its place by signaling the shape of the normalized payload.

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 an output schema present, the description needn't explain return structure, yet it helpfully previews available fields. Combined with defaults and the sibling callout, an agent has everything required to invoke it correctly; only explicit precondition wording is missing.

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 ID, Lang, and Country with formats and defaults. The description largely restates those params (ID format, ISO-2 country default) rather than adding new semantics, which is exactly the baseline-3 case.

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 ('Returns normalized detail for a Chrome Web Store extension or theme') and enumerates the returned fields, so an agent knows exactly what it retrieves. It is clearly distinguishable from chromewebstore_search, which it names as the lookup alternative.

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 explicitly routes search-style queries to chromewebstore_search, giving a clear use/not-use boundary. It stops short of stating the precondition that the agent must already have an item id, but the required ID parameter makes that implicit and the context is otherwise clear.

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