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

The description adds substantial behavioral context beyond annotations: credit charges on the paid provider, the SEO_DATA_UNAVAILABLE error on the default free provider, the requirement to enable the Backlinks API for self-hosted deployments, and the critical distinction that the summary totals and referring-domain list count different populations. This goes well beyond the readOnly/openWorld/idempotent 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?

The description is front-loaded with the return value in the first sentence, followed by tightly packed operational caveats. It is longer than average but each sentence carries distinct and necessary information about billing, availability, and result interpretation.

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 tool with no output schema and annotations that do not cover billing or provider behavior, the description supplies everything an agent needs: what is returned, cost, provider availability, error semantics, and a warning not to misinterpret the two result populations. Nothing essential 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%, so the schema already fully documents projectId, target, and scope. The description does not add parameter-specific syntax or format guidance, so the baseline score of 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?

The description states a specific verb and resource: returns a backlinks profile summary with total backlinks, referring domains, referring pages, rank, plus top referring domains by backlink count. It implicitly distinguishes this overview from sibling tools like get_backlink_anchors by focusing on the aggregate profile rather than detailed anchor text.

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 clearly explains when the tool is available versus unavailable, including the free-provider failure mode and self-hosted API prerequisite. It does not explicitly name a sibling alternative to use instead when the paid provider is unavailable, so it falls short of a full when/when-not/alternatives statement.

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