register_domain

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

No annotations are provided, so the description carries the burden. It discloses that the operation is financial, uses account credit, and that cost must match check_availability and agree_to_terms must be 'yes' or '1'. It also mentions action=REGISTER. This adds useful behavioral context beyond the schema, though it could mention reversibility or response behavior.

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 very concise: three sentences with no wasted words. It front-loads the main action and then provides critical details (cost, terms, warning). Every sentence adds value.

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 4 parameters, no output schema, and no annotations, the description covers the purpose, usage guidance, and two parameter details. However, it does not describe the domain and reason parameters, nor does it indicate the return value or success criteria. This leaves gaps for an agent to fully understand the tool's behavior.

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 0%, so the description must compensate. It adds meaning for cost (pennies, match check_availability) and agree_to_terms (must be 'yes' or '1'), but does not describe domain or reason parameters. Thus, coverage is partial, leaving two parameters undocumented.

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 'Register a new domain using account credit.' It uses a specific verb ('register') and resource ('new domain'), and distinguishes itself from siblings like check_availability, renew_domain, and transfer_domain by focusing on registration.

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 explicitly directs to use check_availability first to obtain the cost, stating 'must exactly match the price from check_availability.' It also warns that this is a financial operation and to verify cost before calling. While it doesn't give explicit scenarios to avoid, the guidance is clear and actionable.

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