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

With no annotations, the description carries the disclosure burden. It discloses that it queries two independent resolvers, returns parsed tags as JSON, and reports disagreements instead of hiding them. It does not mention authentication, rate limits, or error cases, but for a read-only DNS tool the key behaviors are covered.

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 compact and front-loaded with the core function. The opener 'rjhst-email-auth-records:' is redundant with the tool name, and the corporate attribution adds minor noise, but the remaining sentences each earn their place.

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 no output schema, the description explains what is returned (parsed tags as JSON) and the resolver behavior. It lacks details about error handling, absence of records, or input validation, but the overall picture is sufficient for 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 input schema is empty, so the description is the only source of invocation details. It explicitly documents the required query parameter with an example (?domain=example.com), which is essential and compensates fully for the absent schema parameter.

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 states a precise verb and resource: it 'Reads a domain's SPF and DMARC records' and returns parsed tags. It clearly differs from siblings like rjhst-dmarc-reader or x402-dmarc-check by covering both SPF and DMARC and using two resolvers.

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 context is clear: use this when a combined SPF and DMARC read with resolver disagreement detection is needed. It does not explicitly name alternatives or when-not-to-use it, but the scope is stated well enough to route an agent.

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