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

With no annotations provided, the description carries the full burden of behavioral disclosure. It implies a read-only operation ('Check') but does not describe the return format (e.g., boolean or per-chain status) or any potential side effects. It adds some detail by specifying the scope across four chains, but this is insufficient for a tool with no output schema.

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, tightly written sentence that front-loads the action and scope. Every word contributes value, and there is no redundant or vague phrasing. It is an exemplary model of conciseness.

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 check tool with one parameter and no output schema, the description covers the purpose and scope but omits the return format and any prerequisites or edge cases. An agent might need to infer what the result looks like to decide next steps, so the description is adequate but not fully complete.

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?

The input schema covers the only parameter fully, including an example ('alex' or 'alex.i'). The description adds no additional parameter semantics beyond the schema, so a baseline of 3 is appropriate given the high schema 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 clearly states a specific verb ('Check') and resource ('a .i sovereign domain is available for registration'), and specifies the scope ('across all 4 supported chains'). It distinguishes itself from sibling tools like register_domain and estimate_registration by focusing solely on availability, which is a distinct action.

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 provides clear context that this tool checks availability for registration, implying it should be used before attempting to register. However, it does not explicitly name alternatives or give a when-not-to-use condition. The context is sufficient for most agents, but it lacks the explicit routing that would earn a 5.

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