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

Annotations already declare readOnlyHint=true, so the safe read nature is covered. The description adds useful behavioral detail beyond annotations: the fixed limit of 25, the ranking criterion based on the linking domain's authority, and that link counts are included. This gives an agent a clear picture of what the call will return.

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 with no filler. The first sentence front-loads the functional behavior, and the second provides a practical use case. Every word earns its place.

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 one simple parameter and no output schema, the description fully explains what the agent gets back: top 25 linking domains, ranking basis, and link counts. Nothing needed for correct invocation or interpretation 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% and the single 'domain' parameter already has a clear example. The description adds no additional semantic detail about parameter formatting or normalization, so it stays at the baseline for well-covered schemas.

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 the exact operation ('Return'), the resource ('top 25 domains linking to a given domain'), the ordering ('ranked by the linking domain's own authority'), and the included metric ('link counts'). This clearly distinguishes it from sibling tools like backlinks_for_domain, which would focus on individual backlinks rather than ranking linking domains.

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 clear usage context by positioning the tool as 'good for a quick competitive/backlink-profile skim.' It does not explicitly name alternatives or say when not to use it, but the use case is specific enough for an agent to select it appropriately among the siblings.

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