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

Annotations already declare destructiveHint=true, idempotentHint=false, openWorldHint=true, and readOnlyHint=false, so the safety profile is largely covered. The description adds useful auth scoping ('owned by the authenticated customer') but does not explain the actual side effect (blocking outbound transfers), what happens if the lock is already set, or whether the lock is reversible and only via unlock_domain.

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?

A single well-formed sentence with the action and the ownership constraint front-loaded. Nothing is redundant or padded.

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 needn't be described, and the tool is a simple single-parameter mutation. What remains missing is meaningful for a destructive, non-idempotent write: the concrete consequence of locking (transfer prevention), behavior when already locked, and the reversal path.

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?

There is one required parameter with 0% schema description coverage, so the description must compensate. It identifies the argument as a domain belonging to the authenticated customer, which adds an ownership precondition, but gives no format or identifier convention (e.g., 'example.com' vs. internal ID).

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 and resource: 'Enable the registrar transfer lock for a domain', which is precise and clearly the inverse of the sibling unlock_domain. It stops short of naming that sibling, so the agent must infer the pairing from the sibling list rather than from the text.

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 purpose (lock a domain to prevent registrar transfer) and scoped to domains owned by the authenticated customer, but there is no explicit when-to-use, when-not, or pointer to unlock_domain as the reversal path. An agent can infer the context but is given no routing guidance.

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