Check Domain Deliverability

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true. The description adds value by specifying the need for an APIFY_TOKEN, credit consumption, and that it returns a flat JSON row. This provides practical behavioral information beyond annotations. However, it doesn't mention cache behavior or platform limitations for catch-all, which are in parameter descriptions.

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 description is concise with two sentences. The first sentence states the purpose, and the second enumerates outputs and requirements. It is front-loaded with the key action, and every sentence provides value. No unnecessary words.

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 complexity (multiple DNS checks, score, batch processing) and the absence of an output schema, the description comprehensively lists output components and mentions important usage details (token, credits, read-only). It could be improved by noting the cache behavior (skipCache) or the catch-all limitation in the main description, but overall it is sufficient for an agent.

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%, so baseline is 3. The description does not add additional meaning for parameters beyond what the schema provides. It focuses on output and usage, not on parameter details. No extra guidance is given for the 5 parameters.

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's purpose: 'Audit a domain's email deliverability and DNS health.' It specifies the verb 'audit' and the resource 'domain's email deliverability and DNS health,' and lists the specific checks it performs. Since there are no sibling tools, differentiation is not required. The description is specific and actionable.

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 provides context for usage by noting it is 'Read-only' and requires an 'APIFY_TOKEN' and consumes 'Apify credits,' implying it is a paid, safe operation. However, it does not explicitly state when to use this tool versus alternatives, or when not to use it. Given no siblings, this is adequate but could be more explicit.

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