Use DomainDNA MCP with OpenAI Codex CLI

Tech stack, email security (SPF, DMARC, MX provider) and domain age API + MCP. 25 free domains/day.

Remote MCP server (Streamable HTTP), nothing to install. Free: 25 free domains/day · Paid: $5 pack; $19/mo

Set it up

Open ~/.codex/config.toml (create it if needed).
Add the [mcp_servers] table shown and save.
Start Codex; the server's tools are available to the agent.
Ask a question the tools can answer.

Add to ~/.codex/config.toml:

[mcp_servers.domaindna-api]
url = "https://domaindna-api.cybermaxtools.com/mcp?via=use-with-codex"

With a paid key:

[mcp_servers.domaindna-api]
url = "https://domaindna-api.cybermaxtools.com/mcp?via=use-with-codex"
env_http_headers = { "x-api-key" = "CYBERMAX_API_KEY" }

env_http_headers maps the header to an environment variable name, so the key stays in your environment.

Where it goes:

~/.codex/config.toml (or .codex/config.toml in a trusted project)

Config format checked 2026-10-09 against OpenAI Codex CLI's MCP documentation.

Tools you get

Endpoint checked 2026-10-09: https://domaindna-api.cybermaxtools.com/mcp answered an MCP initialize (protocol 2025-06-18) and tools/list with 4 tools, all marked read-only. No key was used and no tool was called.

Tool	What it does	Required inputs
`domain_report`	Tech stack (with evidence), email provider, SPF, DMARC, DNS, RDAP registration (age, registrar, expiry), security headers and site files for one domain, URL or email.	`domain`
`email_security`	MX provider, SPF record and all qualifier, DMARC policy, pct and rua, A/AAAA/NS and TXT verifications for 1-5 domains.	`domains`
`tech_stack`	Technologies (CMS, e-commerce, frameworks, analytics, tag managers, CDN, chat...) with the evidence for each, plus security headers, for 1-3 websites.	`domains`
`domain_registration`	RDAP registration (registrar, created, updated, expires, age in days, status) for 1-10 domains.	`domains`

Test the endpoint from a terminal

This lists the tools without a key and without calling any of them:

curl -s https://domaindna-api.cybermaxtools.com/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

If it does not work

Each server is its own [mcp_servers.<name>] table; keep the name to letters, digits, dashes and underscores.
For a fixed header value instead of an environment variable, Codex also documents http_headers.
The free tier has a daily limit (see the pricing line above); a paid key raises it.

DomainDNA in other clients

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