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

Annotations already mark readOnlyHint and openWorldHint. The description adds meaningful behavioral detail: threshold of linking to MORE THAN ONE domain, domain-level aggregation with no per-link URL/anchor, and free/Pro row and domain-count limits. No contradiction with annotations.

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?

Three dense sentences, front-loaded with the core function before limits/marketing framing. Each clause earns its place: definition, ranking, use case, granularity, and tier constraints.

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 single-parameter read-only tool, the description fully covers inputs, output shape, ranking, granularity, and result limits. No output schema exists, but the description tells the agent enough to invoke it correctly and interpret results.

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%, so the schema already documents 'domains' as root domains to intersect with 2-4 values and free-tier behavior. The description reinforces this but doesn't add significant new parameter semantics beyond the schema; 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?

The description opens with a specific verb and resource ('Multi-domain backlink overlap') and precisely defines output: domains linking to MORE THAN ONE of the given 2-4 domains, ranked by overlap then authority. It also differentiates from siblings like top_linkers_for_domain by emphasizing multi-domain intersection rather than single-domain backlinks.

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?

It gives a clear use case ('who links my whole niche?') and appropriate scenario (must-have publications/roundups competitors share), which implies when to use this over single-domain tools. It doesn't explicitly name alternatives or state when not to use it, so not a 5.

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