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

Annotations already declare read-only, open-world, idempotent, and non-destructive behavior. The description adds crucial return-behavior context absent from annotations and schema: partial=true means timeout/incomplete, null score means unknown rather than zero, credit is refunded, and retry is advised.

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 two sentences, front-loading the purpose and then delivering critical response-interpretation details without any wasted words. Every sentence earns its place.

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 single-parameter lookup tool, the description covers the most important subtle behavior (partial responses and null scores). It falls short on parameter format and does not address when to use this tool versus sibling authority/rank tools, but annotations and the simple schema reduce the overall burden.

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 input schema has one parameter with 0% description coverage. The description adds no meaning beyond the schema, such as whether 'domain' should be a root domain, full URL, subdomain, or whether it must exclude protocol or www. It merely repeats the parameter name in passing.

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: 'Get authority score for a domain.' It is clear what the tool does, but it does not distinguish this tool from similar siblings like get_domain_rank or get_domain_overlap, leaving disambiguation to the agent.

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 gives no guidance on when to choose this tool over alternatives. The only conditional guidance is about interpreting a partial response (retry rather than treating as zero), which is response handling, not tool-selection context.

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