domain-security-mcp-server

Email Header Analyzer

analyze_email_headers

Read-onlyIdempotent

Parse raw email headers to extract SPF/DKIM/DMARC verdicts, key fields, and the full Received hop chain with per-hop delays and total transit time.

Instructions

Parse raw email headers and report the SPF/DKIM/DMARC verdicts (from Authentication-Results), key fields (From, Subject, Date, Message-ID, Return-Path) and the Received hop chain with per-hop delays and total transit time.

Args:

headers (string): the raw email headers.
response_format ('markdown' | 'json'): output format (default 'markdown').

Returns: { auth{spf,dkim,dmarc}, fields{}, hops[{index,from,by,date,delaySec}], totalSec }.

Example: paste the headers from "Show original" in Gmail to trace a message's path and authentication.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`headers`	Yes	The raw email headers to analyze (RFC 5322).
`response_format`	No	Output format: 'markdown' for a human-readable summary (default) or 'json' for the full structured payload.	markdown

Output Schema

TableJSON Schema

Name	Required	Description	Default
`auth`	Yes
`hops`	Yes
`fields`	Yes
`totalSec`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed5 schema fields changedv1.2.1Sep 14, 2026

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

removedInput schema / additionalProperties
```
Removed value: -false
```
addedInput schema / properties / headers / maxLength
```
Added value: +200000
```

changedOutput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

addedOutput schema / properties / fields / propertyNames
```
Added value: +{
+  "type": "string"
+}
```

First observedv1.0.0Jun 8, 2026

TDQS

A4.2/5.0

Behavior4/5

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

Annotations already establish read-only/idempotent/non-destructive behavior. The description adds value by clarifying that verdicts come from Authentication-Results headers rather than live DNS checks, and by detailing per-hop delays and total transit time. It does not mention edge cases like missing Authentication-Results headers, but this is a minor gap given the annotation coverage.

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

Conciseness4/5

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

The description is well organized with a front-loaded summary, Args, Returns, and an Example. It is compact and readable, though the Args and Returns sections partially duplicate the input and output schemas rather than adding entirely new information.

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 two-parameter surface, full schema coverage, rich output schema, and annotations, the description is complete. It provides a concrete example, the output shape, and enough behavioral context for an agent to invoke this tool correctly without needing additional documentation.

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 description coverage is 100%, and the description's Args section mostly restates the schema: headers is a string, response_format is markdown/json with a default. It adds no meaning beyond what the input schema already provides, so the baseline score of 3 applies.

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 uses a specific verb-resource pairing ('Parse raw email headers and report...') and names concrete outputs: SPF/DKIM/DMARC verdicts, key fields, and Received hop chain. This clearly distinguishes it from siblings like spf_check and dkim_check by its raw-header input and transport-path analysis.

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

Usage Guidelines4/5

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

The description gives a concrete scenario: 'paste the headers from "Show original" in Gmail to trace a message's path and authentication.' This makes the intended usage clear, though it does not explicitly contrast the tool with siblings or state when a different tool should be chosen.

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