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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: it warns that premium-domain pricing is non-authoritative and will be recalculated at first-party checkout, which tells the agent not to treat the output as binding for premium names.

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 with no filler, and the core purpose leads. The premium-pricing caveat is a necessary qualifier rather than padding, though it consumes a full sentence.

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 should ideally convey what the response contains (price fields, per-operation breakdown), and with 0% parameter coverage it leaves years undocumented. It covers the important pricing-authority caveat, but not enough for a complete picture of a 3-parameter tool.

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 carry the parameter burden. It partially compensates by naming the three operations (register/transfer/renew), which maps to the operation enum, and by implying the domain input, but the years parameter (1-10, default 1) is never mentioned and there are no format constraints for domain.

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 names a specific verb (return pricing) and resource (standard CAD TLD registration/transfer/renewal), including the currency, which an agent can distinguish from a generic product quote. It doesn't explicitly contrast with siblings like quote_public_product, but the domain-and-CAD framing makes the scope clear.

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?

Usage is only implied: an agent can infer this is the tool to call for domain pricing before a purchase. There is no explicit when-to-use framing, no pointer to check_domain_availability or start_signup as neighboring steps, and no stated prerequisites.

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