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

With no annotations, the description carries the burden of behavioral disclosure. It discloses the subscription requirement, which is useful, but does not mention whether the operation is read-only, rate limits, or response format. Partial transparency only.

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 one concise sentence with no wasted words. It front-loads the action and includes the key prerequisite, making it easy to parse.

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?

The tool has no output schema and no annotations, so the description should explain return values and behavior. It only states 'backlinks and referring domains' without describing the output structure, pagination, or error cases. It is too minimal for complete context.

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?

The schema already fully describes the domain parameter (100% coverage). The description's 'for a domain' adds no extra meaning beyond the schema's 'Domain to check'. No additional parameter context is provided.

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 clearly states the tool checks backlinks and referring domains for a domain. The verb 'check' and resource 'backlinks and referring domains' are specific and distinct from sibling tools like check_ranking or domain_overview.

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?

The description implies use when backlink data is needed and mentions a prerequisite (Backlinks subscription), but does not explicitly state when to use versus alternatives or when not to use. It provides context but no clear exclusions.

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