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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds material context beyond them: the data source (Nuqti link index) and the exact composition of the result, which matters because there is no output schema. It does not mention data freshness, coverage limits, or auth, 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?

Two sentences, both earning their place: the first is a dense but readable inventory of returned metrics, the second gives the usage trigger. Front-loaded with the resource, no padding.

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 carries the burden of explaining returns and does so by enumerating the metrics, and the one required parameter is fully documented. Missing are notes on freshness/coverage of the index estimate or any caveats about range interpretation.

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 coverage is 100% and the single 'domain' parameter is already documented with an example ('example.com'), so the schema does the heavy lifting. The description's phrase 'of a website' only loosely reinforces the param and adds no format rules. Baseline 3 is appropriate.

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 resource (backlink profile of a website) and enumerates exactly what the summary contains: referring domain/link counts, whole-web estimate with range, dofollow/nofollow split, top anchors and TLD mix. It clearly distinguishes itself from a raw list like referring_domains by promising aggregates, though it never names that sibling explicitly.

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?

Provides an explicit trigger phrasing ('Use for "how many backlinks does X have"'), which is a clear when-to-use signal. It stops short of stating when not to use it or pointing to alternatives such as referring_domains for the actual domain list.

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