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

With no annotations, the description carries the full burden of disclosure, and it does so well. It reveals the dry-run/confirm behavior, the contents of the quote (cost, renewal, balance), the payment source, and the owner-only restriction, making the side effects of the tool clear before invocation.

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 sentences, front-loaded with the core purpose, followed by the essential safety caveat about confirm. Every clause earns its place, with no redundant or generic 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 domain-purchase tool with five parameters and no output schema, the description covers the high-stakes aspects: payment source, quote-only behavior, confirmation gate, and permission. The remaining fields are fully documented in the schema, so an agent has enough to call it correctly and safely.

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% and the schema descriptions already explain confirm, quote_id, and max_cost_cents in detail, including 'Required to confirm.' The description adds useful context about the quote flow and prepaid balance, but the schema is doing the heavy lifting, so a baseline 3 is appropriate.

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 the action: 'Buy a domain through Boathouse's registrar and point it at this box, paid from the workspace's prepaid balance.' It names a specific verb, resource, and consequence, and the mention of buying versus pointing/checking distinguishes it from domain_check, domain_point, and domain_attach 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?

It gives concrete operating guidance: without confirm it only returns a quote and buys nothing, and it notes an 'Owners only' permission restriction. It does not explicitly name alternatives such as domain_check for availability checks or domain_point for already-owned domains, so it stops short of full exclusionary guidance.

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