validate_email_auth

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

Annotations already establish read-only and open-world behavior. The description adds meaningful operational detail: it checks existence, validates each record, and returns raw records. This gives agents a clear model of what the tool does beyond the annotations, though it does not discuss edge cases like missing DNS records or partial failures.

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?

Two sentences with no filler. The main action, record types checked, and return behavior are all stated compactly and front-loaded.

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 simple one-parameter, read-only tool with no output schema, the description covers the essential behavior: what records are checked, what outcome is determined, and what is returned. It is slightly sparse on output details and error behavior, but not to a degree that would prevent correct invocation.

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 covers 100% of the single parameter with an informative description including format guidance and an example. The tool description itself adds no parameter semantics beyond the schema, so the baseline of 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?

The description names a specific verb ('Validate') and a specific resource ('email authentication records (SPF, DKIM, DMARC) for a domain'). It clearly distinguishes this from sibling tools like dns_lookup by focusing on authentication record validity and raw record retrieval.

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 when to use it: whenever SPF, DKIM, or DMARC records need validation for a domain. However, it does not explicitly mention alternatives or state when not to use it, leaving usage guidance to inference.

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