Domain Availability Check

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds behavioral context by specifying the return value format (boolean domainAvailability) and the trade-offs between sources (speed vs. authority). No contradictions with annotations.

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?

Two sentences that are front-loaded with the key action and return value, followed by practical source selection advice. Every sentence adds value with no waste.

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?

Given the tool's simplicity (2 parameters, no output schema, boolean return), the description fully covers usage scenario, parameter semantics, and return format. No gaps remain for effective tool invocation.

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 already provides 100% coverage with descriptions for both parameters. The description adds value by reinforcing the trade-off between dns and whois (faster vs. more accurate), complementing the schema. This gives the agent additional decision-making context beyond the schema.

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 the tool checks a single domain for registration availability and returns a boolean. It explicitly distinguishes from bulk and suggestions tools by specifying 'single domain name', which differentiates it from siblings like domain_bulk_check_availability.

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?

Provides explicit guidance on when to use each source: whois for accuracy, dns for speed. This helps the agent select the appropriate option. However, it does not explicitly contrast all sibling tools, but the single-domain focus is clear.

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