Email Dns Check

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

With no annotations, the description carries the full behavioral burden, but it only states which records are checked. It does not disclose whether the tool is read-only, how errors or missing records are handled, what resolver or timeouts are used, or what the response structure looks like—significant gaps for a network tool with no output schema.

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?

A single front-loaded sentence that identifies the action and scope with zero filler. Every word earns its place, and the optional DKIM qualifier is properly embedded rather than buried.

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 two-parameter read-only DNS check, the description gives enough to understand the tool's scope and call it with a domain and optional selector. However, with no annotations and no output schema, it leaves the agent guessing about return format, error behavior, and resolution semantics—gaps that a slightly richer description could close.

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 the schema already documents both parameters. The phrase 'optional DKIM' adds a small piece of meaning: DKIM checking is conditional and tied to the dkim_selector parameter, which the schema does not itself explain. Beyond that, the description adds no parameter detail.

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 action ('Check') and precisely lists the email-related DNS record types (MX, SPF, DMARC, optional DKIM), which clearly distinguishes it from generic DNS query siblings like dig_query or nslookup_query. It stops short of explicitly naming those siblings, but the record-type specificity makes the purpose unambiguous.

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?

Usage is implied by the email-focused record types: an agent can infer this is the right tool for auditing a domain's email authentication DNS setup. However, no explicit when-to-use or when-not-to-use guidance is given, and no alternatives (e.g., dig_query for raw DNS lookups) are mentioned.

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