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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description adds meaningful context beyond that: the secret is not cached or stored but fetched on demand, and access is restricted to domains owned by the authenticated customer. It does not disclose what happens when ownership checks fail or whether the code expires, keeping it short of a 5.

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 short sentences with no waste, front-loading what is returned and then the on-demand access property. Every sentence earns its place.

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?

An output schema exists so return values need not be documented, and the ownership precondition plus on-demand semantics cover the essentials for a single-parameter read tool. Only error/edge-case behavior is missing.

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 0% for the single 'domain' parameter, so the description must compensate. It adds the important constraint that the domain must be owned by the authenticated customer, but gives no format guidance (bare name vs FQDN) or behavior for unknown domains.

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 (return) and resource (EPP transfer auth code) scoped to a domain owned by the authenticated customer. It implies but does not explicitly name its nearest sibling, regenerate_transfer_auth_code, so an agent must infer the distinction between reading and regenerating.

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 secret is fetched only on demand" hints that this is a non-mutating retrieval and that a code already exists, which implicitly separates it from regenerate_transfer_auth_code. However, no explicit alternative is named and no conditions or error cases (e.g. domain not owned, domain locked) are given.

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