Check several domains

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

Annotations already declare readOnly, idempotent, and openWorld, so safety is covered. The description adds genuine non-structured behavior: the 50-item cap and that results are deduplicated to unique names and returned in order — details an agent needs to map results back to inputs. It omits any note that the insights path is slower, which lives only in the 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?

A single sentence with zero filler, front-loading the batch capability and following with the result contract (one per unique name, ordered). Nothing is redundant.

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?

With an output schema present and annotations covering safety, the description is nearly complete for correct invocation: it gives limit, dedup, and ordering. The only gap is a hint that enabling insights changes latency/cost, which the agent must discover from the parameter description.

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 50% and both properties carry descriptions, so baseline 3 applies. The description restates the 50-item cap already enforced by maxItems and says nothing about the insights flag, adding little beyond the schema text.

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 (checks) and resource (domain names) with batch scope ('up to 50 at once') and return shape ('one result per unique name, in order'). This implicitly separates it from the single-domain sibling check_domain, though it never names the sibling explicitly.

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 batch-oriented phrasing implies when to prefer this over check_domain, but there is no explicit 'use this when you have multiple domains, use check_domain for one' routing, and no mention of check_name_across_tlds or suggest_domains. Usage must be inferred.

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