Email Authentication Check

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

Annotations indicate readOnlyHint=true, and the description aligns by describing validation and recommendations without mention of destructive actions. It adds context beyond annotations (e.g., mandatory DMARC requirement).

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?

Three sentences with no fluff. The purpose is front-loaded, and every sentence provides essential information (what it does, what it checks, a relevant note).

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 tool with one parameter and no output schema, the description is complete. It covers the full scope of the tool's functionality and adds practical context about mandatory DMARC, making it self-contained.

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?

The schema describes the parameter 'url' as 'Website URL or domain to check'. The description adds meaning by specifying it checks email authentication records, which clarifies the domain extraction logic. Baseline 3 due to high schema coverage, but description adds value.

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 it validates DMARC, SPF, and DKIM records for a domain, checks for misconfigurations, and provides fix recommendations. This distinguishes it from sibling tools like audit_site or check_dns which have different purposes.

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 implies use for checking email authentication but does not explicitly state when to use versus alternatives like check_dns. No exclusion criteria or when-not-to-use guidance is provided.

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