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

Annotations already declare destructiveHint=true, idempotentHint=false, and readOnlyHint=false, so the safety profile is covered. The description adds useful context by stating that the old code is invalidated and that the domain must be owned by the authenticated customer, which goes beyond the annotations and helps the agent understand the side effect and authorization scope.

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 a single, well-structured sentence that front-loads the action, return value, ownership constraint, and side effect. Every clause carries useful information with no redundancy.

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 explained in detail, and the annotations already cover the destructive and non-idempotent nature. The description is nearly complete for a one-parameter mutation tool, though it could explicitly mention the sibling read tool or clarify parameter format for full completeness.

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% for the single 'domain' parameter, so the description must compensate. It adds the meaningful constraint that the domain must be owned by the authenticated customer, but it does not clarify the expected domain format (e.g., full domain name versus ID) or any other parameter semantics, leaving a gap.

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 verb and resource: regenerate an EPP transfer auth code and return a new one. It clearly conveys the action and effect, but it does not explicitly distinguish itself from the sibling tool get_transfer_auth_code, leaving the agent to infer the difference between fetching versus 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?

Usage is implied by the word 'regenerate' and the note that the old code is invalidated, which suggests this is for replacing an existing code rather than retrieving one. However, there is no explicit guidance naming get_transfer_auth_code as the alternative or stating when regeneration is appropriate versus simply reading the existing code.

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