check_domain

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

With no annotations, the description carries the full burden and does meaningful work: it declares the tool is side-effect free (no orders, no charges, no registration) and discloses the failure mode — 'unknown' when upstream fails, restricts the domain, or requires manual review. It omits auth/rate-limit context, which keeps it below a 5.

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?

Four short sentences, front-loaded with the core capability, then input format, then return/failure semantics, then the negative scope. Every sentence carries distinct information and none restate the tool name or schema.

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?

There is no output schema, so the description must describe results — and it does, covering both the success payload (availability + first-year USDT price) and the 'unknown' fallback condition. For a single-parameter read-only lookup, nothing an agent needs before calling is missing.

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 single parameter has 0% schema description coverage, so the description must compensate, and it does: it specifies a fully-qualified DNS domain, gives 'example.com' as a concrete example, and notes IDN must be in xn-- ASCII form. That is real format guidance beyond the bare 'domain' string type, though it doesn't cover edge cases like trailing dots or length limits.

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?

States a precise verb and resource ('Check a single domain') and names exactly what it returns: confirmed availability plus a first-year USDT preview price. The 'single domain' scope and the negative clause ('Does not create orders, charge accounts, or register domains') make the boundary against ordering tools unmistakable even though no siblings are listed.

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 makes the use case clear (pre-purchase availability/price lookup) and explicitly rules out adjacent operations by stating it does not create orders, charge accounts, or register domains. It stops short of naming a companion ordering tool or stating prerequisites, but the when/when-not split is present.

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