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

Beyond the sparse annotations, the description adds real behavioral context: it is a bounded/summary projection, does not paginate or fan out to other providers, and 'unapproved costs prevent execution' signals a cost-approval gate. It also warns the proprietary rankings are not Google ratings or measured traffic, which meaningfully frames the output semantics.

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?

Five short, front-loaded sentences with no filler; each clause carries a distinct caveat. Slightly dense jargon ('bounded summary projection') keeps it from a 5.

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, nested params, and annotations that only give readOnlyHint=false/openWorldHint=true, the description should say more about what the summary contains and how it is shaped. It covers constraints and metric caveats but leaves the actual return content and the meaning of readOnlyHint=false unexplained.

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 0% for a nested target object with a DOMAIN/PAGE enum. The description only hints 'preserve target kind', which gestures at the enum but does not explain what kind means, the expected target string form (domain vs URL), or the 2048-char limit, so it falls short of compensating.

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 identifies the resource (backlink index summary for a target), but the verb is abstract ('bounded summary projection') rather than a plain statement like 'returns a high-level backlink profile summary'. It also fails to differentiate from the many backlink siblings (backlink_records, referring_domains, domain_backlink_pages, backlink_anchors), so an agent cannot readily tell which backlink tool to pick.

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?

There is no statement of when to use this versus detailed backlink siblings. It only notes 'no pagination or additional provider calls' and cost gating, which describes execution behavior rather than selection criteria.

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