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

No annotations are provided, so the description must fully disclose behavioral traits. It only states it checks availability and is free, but does not disclose return format, side effects, rate limits, or what happens if the domain is unavailable. This is insufficient for a mutation-free tool.

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 a single, concise sentence that front-loads the main action. Every word serves a purpose with no redundancy.

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?

Given the single parameter, no output schema, and no annotations, the description lacks detail on return values (e.g., boolean, response structure). For a check tool, this is insufficient for an AI agent to interpret results correctly.

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?

With 0% schema description coverage, the description adds some meaning by specifying allowed TLDs (.com/.ru/.рф). However, it does not clarify input format (e.g., with or without TLD, example) beyond that. Baseline 3 is appropriate as it partially compensates but not fully.

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 verb 'Check' and the resource 'domain', with specific TLDs (.com/.ru/.рф). It differentiates itself from siblings like register_ru_domain (registration) and check_balance (balance inquiry).

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 mentions 'Free, no balance needed,' which implies it can be used without cost, suggesting it's safe to use anytime. However, it does not explicitly state when not to use it or compare to alternatives like register_ru_domain for registration.

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