Check email-domain health (MX / SPF / DMARC)

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

No annotations are provided, so the description carries the burden of disclosure. It reveals the specific DNS records checked, but does not explain the response format, scoring criteria, or any potential side effects/limitations. For a read-only check tool, some behavioral context is missing.

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?

Exceptionally concise: two sentences that immediately convey what the tool does, what it checks, and when to use it. No wasted words or redundant details.

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?

The tool has no output schema, so the description should compensate by explaining return values. It mentions an 'overall health score' but does not describe the response structure, interpretation, or error handling. For a simple single-parameter tool, it is adequate but leaves the agent uncertain about the result format.

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 description coverage is 100% and the single 'domain' parameter is well-documented with an example. The description adds no additional parameter semantics beyond what the schema already provides, so baseline 3 is appropriate.

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?

Description clearly states it checks DNS and deliverability health of an email domain, listing MX, SPF, DMARC, and health score. This distinguishes it from sibling tools like verify_email which check individual addresses rather than domain-level configuration.

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 describes two use cases: diagnosing bounced domains and validating sending domains. It does not explicitly name alternative tools, but the domain-vs-address distinction is clear from the description and sibling context.

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