dp_check_email_securityCheck a domain's email authentication posture — SPF, DKIM, and DMARC DNS records — and return an A–F grade with explanations. Read-only DNS lookups; no email is sent or stored.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain to check, e.g. 'example.com'. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, but the description adds valuable context by specifying 'Read-only DNS lookups; no email is sent or stored.' This reassures about side effects and aligns with the annotation without contradiction, going beyond just repeating the hint.
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 two sentences, front-loaded with the primary action, and every phrase adds value. It efficiently conveys purpose, method, and side-effect safety without redundancy.
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 tool with one parameter and no output schema, the description covers the action, the records checked, the return format (A–F grade with explanations), and the read-only nature. It is fully sufficient for an agent to understand and invoke the tool.
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%, with the sole parameter 'domain' clearly described. The description adds little beyond the schema, only implying the domain parameter through the overall purpose. Baseline 3 is appropriate since the schema already documents the parameter fully.
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 uses a specific verb ('Check') and resource ('a domain's email authentication posture'), explicitly listing SPF, DKIM, and DMARC, which distinguishes it from sibling checks like breach, password, or WHOIS tools. The mention of returning an A–F grade further clarifies its unique purpose.
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 clearly implies the tool is for checking email security, giving context for when to use it. However, it does not explicitly mention alternatives or when-not-to-use, which would earn a 5. The context is strong enough to infer appropriate usage.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.