scan.mx Email Diagnostics

Check MX records

check_mx

Read-only

Check the MX records of a domain: presence, hostnames, resolution, null-MX, and common misconfigurations.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`domain`	Yes	The domain to check, e.g. example.com. No scheme or path.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`grade`	No
`score`	No
`checks`	No
`domain`	Yes
`provider`	No
`sections`	No
`selector`	No
`permalink`	No
`smtp_note`	No
`created_at`	No
`expires_at`	No
`updated_at`	No
`smtp_status`	No
`poll_after_seconds`	No

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

First observedJul 9, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already mark the tool as read-only and open-world. The description adds value by detailing what specific checks are performed (presence, hostnames, resolution, null-MX, misconfigurations), providing behavioral context beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence that is front-loaded with the main action and then lists specific checks. No wasted words; concise and clear.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity (one parameter, full schema coverage, output schema present, annotations clear), the description adequately covers the checks performed. Slightly lacking in detail about the output format, but overall complete for the context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema description coverage, the schema already documents the domain parameter. The description rephrases but does not add new semantic details about the parameter, so baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it checks MX records of a domain, listing specific aspects: presence, hostnames, resolution, null-MX, and common misconfigurations. This distinguishes it from sibling tools that check other DNS records.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage when assessing email server configuration via MX records, but does not explicitly state when to use this tool versus alternatives, nor does it provide when-not or exclude conditions.

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

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TDQS

A4.3/5.0

Disambiguation5/5

Each tool targets a distinct deliverability concern: blacklist status, DKIM, DMARC, full domain scan, MX, and SPF. There is no overlap in functionality; even check_domain's comprehensive check is clearly differentiated from the individual checks.

Naming Consistency5/5

All tools follow a consistent check_[resource] naming pattern (e.g., check_blacklist, check_dkim, check_dmarc). This pattern is uniform and predictable, making it easy for an agent to infer tool purposes.

Tool Count5/5

Six tools is an ideal scope for an email diagnostics server. Each tool covers a core aspect of deliverability (MX, SPF, DKIM, DMARC, blacklists, and a full scan), with no redundancy. The count feels complete and focused.

Completeness4/5

The tool set covers the major email deliverability checks (MX, SPF, DKIM, DMARC, blacklists, and a full domain scan with optional SMTP probe). A minor gap might be the lack of a dedicated tool for SPF or DKIM record modification, but for a diagnostic-only server, the coverage is robust and actionable.

Resources

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