check_domain_availability

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

The readOnlyHint annotation already declares the read-only nature, and the description reinforces it with 'Read-only; no payment method required.' It adds value beyond annotations by disclosing that pricing is indicative, per-term (registration/renewal), and converted from cents to whole currency units. No contradiction with 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?

Three short sentences front-load the primary function first, then add the read-only/payment guard, then the accuracy tip. Every sentence adds a distinct fact and there is no filler.

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 read-only check with 3 well-documented parameters and no output schema, the description conveys the core result domain: availability plus registration/renewal pricing in whole units. It does not specify the exact response structure, but the schema covers optimizeFor behavior and the tool is simple enough that the description is largely sufficient.

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%, and the schema already explains domains, iscCode, and optimizeFor (including the SPEED/ACCURACY trade-off). The description adds little beyond 'one or more domains' and a pointer to ACCURACY for a live check, so it mostly relies on the schema's detailed property descriptions.

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 opens with a specific verb ('Check') and resource ('whether one or more domains are available for registration'), making the primary function concrete. It also states 'Read-only; no payment method required,' which implicitly distinguishes it from registration, quoting, and suggestion siblings.

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 usage context: it is a read-only pre-registration check with no payment required, and it advises 'Use ACCURACY for a live registry check.' However, it never explicitly names alternatives or states when to prefer this tool over list_domains, suggest_domains, or get_registration_quote, so routing between tools is left to inference.

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