domain-security-mcp-server

BIMI Check

bimi_check

Read-onlyIdempotent

Check a domain's BIMI DNS record to verify the brand logo shown in authenticated email and confirm it meets the DMARC enforcement requirement.

Instructions

Check a domain's BIMI record (default._bimi. TXT), which points to the brand logo (and optional VMC) displayed next to authenticated mail. BIMI requires an enforced DMARC policy to take effect.

Args:

domain (string): the domain to check.
response_format ('markdown' | 'json'): output format (default 'markdown').

Returns: { found, record, findings[] }.

Example: "Does cnn.com have BIMI set up?" -> bimi_check(domain="cnn.com").

Input Schema

TableJSON Schema

Name	Required	Description	Default
`domain`	Yes	Domain to check, e.g. 'example.com'.
`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
`found`	Yes
`domain`	Yes
`record`	No
`findings`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 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 / domain / maxLength
```
Added value: +253
```

changedOutput schema / $schema

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

First observedv1.0.0Jun 8, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds meaningful context about the lookup target, the DMARC prerequisite, and the returned structure. No contradiction exists between the description and 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 compact, front-loaded, and well organized with Args, Returns, and Example sections. Every line carries useful information, and there is no filler or repetition beyond what serves clarity.

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?

For a simple read-only DNS record check with full schema documentation and an output schema, the description is complete. It includes the exact lookup name, the prerequisite, the return shape, and a real-world example. Nothing essential is missing for an agent to invoke it correctly.

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

Parameters4/5

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

Schema coverage is 100%, so parameters are already documented well. The description still adds value with a concrete usage example and the default response_format behavior. This goes beyond the baseline without introducing ambiguity.

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 identifies the exact resource being checked (the default._bimi.<domain> TXT record) and the action (check), plus what the record is used for. This makes it clearly distinguishable from sibling tools like spf_check, dmarc_check, and dkim_check. The example reinforces the purpose with a concrete domain.

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 states the key prerequisite: BIMI requires an enforced DMARC policy to take effect. This gives the agent useful context about when this check is relevant. It does not explicitly name alternative tools, but the record-specific definition makes the intended use obvious.

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