Register a new domain and attach it to a site

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

With no annotations, the description carries the full burden. It discloses pricing (at-cost, 50 credits + pass-through), automatic DNS and Pages wiring, the strict price-match guard, a $50 cap, and the Active Site cost implication. It omits failure scenarios but is otherwise highly transparent.

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 moderately long but organized with clear sections (precondition, cost, implications). Every sentence adds relevant information and nothing is wasted, though it could be tightened slightly.

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?

Despite no output schema and no annotations, the description thoroughly covers purpose, preconditions, costs, and side effects. It does not describe the return value, which is a minor gap, but the tool context is well understood.

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% for all four parameters, so the baseline is 3. The description reiterates the price-match requirement and slug source, adding minimal new semantics beyond what the schema already documents.

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 action: 'Purchase a domain via Cloudflare Registrar at-cost and attach it to a deployed Warpweb site in one shot.' It clearly identifies the resource (domain and site) and distinguishes from sibling attach_domain by emphasizing the combined purchase+attach flow with automatic DNS wiring.

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 an explicit precondition: call check_domain first and pass an exact matching price. It also references create_site for the pagesProjectName. However, it does not explicitly name alternatives like attach_domain for already-owned domains, leaving that to inference.

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