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

Annotations already declare readOnlyHint, openWorldHint, and destructiveHint. The description adds meaningful behavioral context: 'Nothing here fetches the page, so nothing here can be blocked.' This goes beyond the annotations and helps set expectations about reliability.

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 description is compact and well-structured: core outputs first, then use cases, then behavioral caveat. Every sentence earns its place, with no filler or repetition of schema/annotation data.

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?

The output schema and annotations cover return values and safety, and the description provides strong use-case context. However, the complete lack of parameter documentation for limit and backlinks leaves a meaningful gap for an agent deciding how to invoke the tool.

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 0%, and the description does not explain the url format, limit, or backlinks parameter. The phrase 'who links to it' indirectly hints at backlinks, but limit is entirely undocumented, leaving the agent without enough information to tune the call.

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 opens with concrete data points the tool returns: domain age, registrar, hosting, and backlinks. It also explicitly contrasts itself with page scraping ('off-page questions a page scrape cannot answer'), which distinguishes it from siblings like scrape and extract.

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?

The description gives clear when-to-use scenarios: comparing competitors, judging a source, and checking whether a domain was registered recently. It implies the alternative (page scraping) but does not name a specific sibling tool or explicitly state when not to use it.

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