BlackVeil DNS & Email Security Scanner

check_dkim

Read-onlyIdempotent

Look up DKIM records for a domain. Probes common selectors, validates the signing algorithm used for outgoing email (RSA-1024/2048, Ed25519), and reports key strength. Use to verify that outbound email signatures are cryptographically sound. Part of the scan_domain audit.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "domain": "<domain>"
    },
    "name": "check_dkim"
  }
}

Input Schema

Name	Required	Description
`domain`	Yes	Domain, e.g. example.com
`format`	No	Output verbosity.
`selector`	No	DKIM selector. Omit to probe common ones.
`force_refresh`	No	Bypass the cache.

Output Schema

Name	Required	Description	Default
`score`	Yes
`passed`	Yes
`partial`	No
`category`	Yes
`findings`	Yes
`checkStatus`	No
`verdictWithheld`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedNov 12, 2026

changedInput schema / properties / domain / description

Previous value: -"Domain to check (e.g., example.com)"New value: +"Domain, e.g. example.com"

changedInput schema / properties / force_refresh / description

Previous value: -"Bypass cache and run a fresh check. Useful after DNS changes."New value: +"Bypass the cache."

changedInput schema / properties / format / description

Previous value: -"Output verbosity. Auto-detected if omitted."New value: +"Output verbosity."

Changed1 schema field changedOct 25, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```
Changed1 schema field changedOct 5, 2026
- addedOutput schema / properties / verdictWithheld
```
Added value: +{
+  "type": "boolean"
+}
```
Changed2 schema fields changedAug 18, 2026
- addedOutput schema / properties / checkStatus
```
Added value: +{
+  "type": "string"
+}
```
- addedOutput schema / properties / partial
```
Added value: +{
+  "type": "boolean"
+}
```

Changed1 schema field changedJul 2, 2026

addedInput schema / properties / force_refresh

Added value: +{
+  "description": "Bypass cache and run a fresh check. Useful after DNS changes.",
+  "type": "boolean"
+}

Changed1 schema field changedMay 26, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "additionalProperties": {},
+  "properties": {
+    "category": {
+      "type": "string"
+    },
+    "findings": {
+      "items": {
+        "additionalProperties": {},
+        "properties": {},
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "passed": {
+      "type": "boolean"
+    },
+    "score": {
+      "type": "number"
+    }
+  },
+  "required": [
+    "category",
+    "score",
+    "passed",
+    "findings"
+  ],
+  "type": "object"
+}

First observedApr 21, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already declare this a read-only, idempotent, non-destructive, open-world probe, so the safety bar is low. The description adds real behavior the annotations do not: it actively probes common selectors, enumerates the algorithm families it checks, and reports key strength. It does not mention the cache or the cost of probing many selectors, which the force_refresh parameter hints at but never explains here.

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?

Three sentences, front-loaded with the action and result, then the algorithm detail, then the routing hint. Nothing is redundant and nothing buries the lede.

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?

With an output schema present and full schema coverage, the description need not explain return shape. It correctly covers the remaining unknowns: what gets probed, what gets validated, and how the tool relates to the wider audit.

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%, so every parameter including selector, format, and force_refresh is already documented inline. The description reinforces the selector-probing behavior but adds no syntax, default, or constraint detail beyond the schema, which is exactly the baseline-3 case.

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 opens with a specific verb and resource ('Look up DKIM records for a domain') and immediately narrows scope to signing-algorithm validation and key strength. That is enough to separate it from siblings like check_spf and check_dmarc without opening any schema.

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?

It gives a clear use case ('verify that outbound email signatures are cryptographically sound') and positions itself inside the broader scan_domain audit, which tells an agent when to reach for it versus the umbrella tool. It does not state any when-not condition, so it stops short of the top band.

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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