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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuinely useful context beyond the annotations: 'This makes one billable DataForSEO request,' a cost/latency signal an agent can factor into invocation decisions.

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 front-loaded and functional: the first states the use case and scope, the second discloses the billing cost. No filler or redundancy.

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?

For a simple one-param read tool with no output schema, the description covers what data it returns (backlink and referring-domain totals) and the cost. The only missing piece is any pagination, limit, or return-shape note, which is minor here.

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% for the single `target` parameter, and the schema already documents that it's a domain/subdomain without URL scheme or path. The description adds no format or syntax detail beyond that, 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?

States a specific resource (backlink and referring-domain totals) for a domain, which is enough to distinguish it from the sibling dataforseo_google_serp and dataforseo_ranked_keywords tools, which cover different DataForSEO resources. It doesn't explicitly name those siblings, but the resource is clear.

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 a usage trigger ('when a team member asks for a domain's backlink and referring-domain totals') but names no alternatives or when-not conditions. The trigger implies when to use it, but routing vs the other DataForSEO tools is left to inference.

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