scan.mx Email Diagnostics

Check DMARC

check_dmarc

Read-only

Check the domain DMARC policy at _dmarc: presence, policy strength (none/quarantine/reject), and reporting.

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

A4.1/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds context by specifying what is checked (presence, policy strength, reporting). It does not contradict annotations and provides useful behavioral details 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 of 14 words, front-loaded with the action and key details. It is concise with no wasted words.

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

Completeness5/5

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

Given the tool has an output schema (not shown) and is simple (1 parameter, read-only), the description covers the essential aspects: presence, policy strength, and reporting. It is complete enough for an agent to understand usage.

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?

Schema coverage is 100% with a clear parameter description for 'domain' including an example and constraints. The tool description does not add significant new information about the parameter beyond what is in the schema. Baseline 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 the action (check), the resource (domain DMARC policy at _dmarc), and the specifics (presence, policy strength, reporting). It distinguishes from sibling tools like check_spf or check_dkim by focusing on DMARC specifically.

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 the tool should be used to check DMARC policy but does not explicitly state when to use it over alternatives like check_spf or check_dkim. No exclusions or prerequisites are mentioned.

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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