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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real value by clarifying that disclosures are returned 'as the store renders them' and itemizing the disclosure components, which tells the agent what kind of content to expect. It does not mention rate limits or regional-variation caveats, keeping it short of 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?

Purpose is front-loaded and the alternative is placed at the end, which is good ordering. However, the ID and Country parameter sentences duplicate the schema definitions word-for-word while Lang is omitted, so not every sentence earns its place and redundancy slightly dilutes the description.

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 explained, yet the description still usefully summarizes what the payload contains. For a read-only lookup with full schema coverage, an agent has everything needed to invoke it correctly; only minor gaps remain (e.g., behavior when an item has no privacy disclosure).

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 including their defaults. The description largely restates those param definitions verbatim ('Defaults: country=us, lang=en', the ID example string), adding no syntax or constraint beyond structured fields, so the 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?

Specific verb 'Returns' plus resource 'an extension's privacy disclosures', and it enumerates the actual contents (data-use statement, data-collection flag, data-handling declarations, privacy-policy link). It explicitly names the sibling it is not (chromewebstore_permissions), so an agent can route between them without opening either schema.

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?

Explicit routing: 'Use chromewebstore_permissions to retrieve a Chrome Web Store item's declared permissions' clearly signals the boundary between privacy and permissions. There is no explicit when-not or coverage of other siblings like chromewebstore_item, but the key alternative is named.

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