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

With no annotations, the description carries the full behavioral burden and does disclose a key trait: passing a bare name expands to eight TLDs (.com, .dev, .app, .io, .co, .net, .ai, .org) rather than a single lookup, and it returns price. It does not mention rate limits, auth requirements, or whether pricing is per-TLD.

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?

Two tight sentences, front-loaded with the purpose and followed by the input semantics. The parenthetical TLD list is information-dense and earns its place; 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?

No output schema and no annotations, so the description must stand alone, and it covers both input interpretation and the headline return value (price/availability). It is nearly complete for a simple lookup, though it omits result shape details like whether all TLDs are always returned.

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 coverage is 100%, so the baseline is 3, but the description adds genuine meaning beyond the schema's terse 'e.g. acme or acme.dev' by explaining exactly what a short name does (expansion across TLDs) versus submitting a full domain. This materially changes how an agent would call it.

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 specific verb and resource ('Check if domains can be bought here, with price'), making the availability-check role clear against siblings like domains.buy, domains.list, and domains.verify. It does not explicitly name or contrast those siblings, so it falls short of 5.

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 'can be bought here' framing implies this is a pre-purchase availability lookup, but the description never states when to use it versus alternatives such as domains.buy or domains.list, nor any exclusions. Usage is only inferable from context.

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