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

Annotations already cover readOnly, openWorld, and idempotent, so the safety profile is known. The description adds useful context (which patterns, default TLD), but doesn't mention rate limits, number of suggestions, or the network-dependent nature beyond what openWorldHint implies.

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 tight sentences with the generation logic front-loaded and the usage trigger second. No filler.

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 read-only, two-parameter, idempotent tool with no output schema and full schema coverage, the description is nearly complete. It could mention how many results or the output shape, but the essentials for correct invocation are present.

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 coverage is 100%, with the tld enum and name pattern fully documented in the schema. The description echoes the '.com by default' default but adds no syntax or format beyond the schema, so baseline 3 applies.

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?

Specific verb (generates, checks) and resource (name variants, domain availability), and it even enumerates the variant patterns. An agent can distinguish this from check_domains and check_name without opening a schema.

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?

Explicitly states the trigger condition 'Use when the exact name is taken,' which gives clear when-to-use guidance. It does not explicitly name sibling alternatives or when-not-to-use, keeping it short of a 5.

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