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

Annotations already indicate readOnlyHint=false, destructiveHint=false, and idempotentHint=true, covering the basic safety profile. The description adds the registrar-lock behavior and intent, but does not disclose additional details such as whether the lock takes effect immediately or whether it affects in-progress transfers.

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, front-loaded sentence that conveys action, resource, and rationale without filler. The 'lockDomain:' prefix is mildly redundant with the tool name but does not detract from clarity.

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 simple two-parameter mutation with full schema coverage and safety annotations, the description is nearly sufficient. It lacks only explicit guidance on when to prefer this over unlockDomain or how the lock interacts with transfer workflows, but those are minor for this tool's scope.

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 100%, with both domain and sessionKey already documented. The description adds no parameter-level meaning beyond the schema, which is acceptable given full coverage.

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 action ('Enable registrar lock') on a specific resource ('a domain') and gives the purpose ('prevent unauthorized transfers'). This clearly differentiates it from sibling tools like unlockDomain and updateDomainPrivacy.

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 description implies when to use this tool: when you want to prevent unauthorized transfers. However, it does not explicitly mention alternatives or when not to use it, such as referencing unlockDomain for reversal or noting conditions like pending transfers.

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