Checks whether a domain name is available for registration by querying the authoritative registry. Use it to verify domain availability before buying or registering a domain.
Performs authoritative registry socket query to verify whether a domain name is available for registration.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain name to check (e.g. mynewbrand123.com) |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It does disclose the query mechanism ('authoritative registry socket query'), which tells the agent this is an external authoritative registry lookup and implies a safe read operation. However, it omits rate limits, timeouts, return format, and error behavior, leaving significant gaps for a no-annotation tool.
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, front-loaded sentence that states the action and mechanism without any wasted words. It is appropriately sized for a simple one-parameter tool.
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 availability check with no output schema and no annotations, the description covers the core action but does not indicate the return value (e.g., boolean availability), error conditions, or any safety profile. It is minimum viable but leaves clear gaps.
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 schema has 100% description coverage for the single 'domain' parameter, including an example. The description adds no additional parameter semantics beyond what the schema already provides, so the baseline of 3 is appropriate.
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 + resource: 'verify whether a domain name is available for registration.' The mechanism ('authoritative registry socket query') further clarifies it is a registry check, implicitly distinct from a DNS resolver. However, it does not explicitly name or differentiate from the sibling tool resolve_dns_records.
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 only restates the tool's purpose. It gives no guidance on when to use this tool versus alternatives (e.g., resolve_dns_records), no prerequisites, and no exclusions. An agent must infer usage entirely from the name and description.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.