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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), yet the description adds real operational context: it performs up to ~30 live lookups, is slower than a single check, and filters the response down to only available candidates. That latency and filtering disclosure is valuable beyond the annotations, though it doesn't mention rate limits or failure behavior for individual lookups.

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 trigger condition is front-loaded in the first clause, followed by the mechanics and the performance caveat. It is a single dense paragraph with little waste, though the enumeration of candidate-generation strategies is slightly verbose for a 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?

There is no output schema, and the description compensates by stating exactly what comes back ('returns only the ones that are not taken'), plus the input shape and the cost profile. An agent has everything it needs to decide whether to call this and what to expect.

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?

Only one parameter exists and schema coverage is 100%, so the schema already fully documents 'domain' including length bounds and format. The description restates the expected input with an example ('acme.com'), which is consistent but adds no syntax or constraint detail beyond the schema, so the 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?

States a specific verb and resource (proposes alternative domain endings/words for a taken domain) and enumerates the concrete strategies: TLD swaps, added words, domain hacks, related words. It is clearly distinguished from the sibling check_domain_availability by describing a multi-candidate generative workflow rather than a single lookup.

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?

Gives an explicit trigger condition: use it when the desired domain is taken or the user asks for other options for a name. It also implicitly contrasts with a single check ('Slower than a single check'), but it never names the sibling tool check_domain_availability, so routing still requires a small inference.

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