checker-mcp — Claude Code MCP server: what it does, how to install
A local-first MCP server for auditing domain security and privacy. It runs 17 live checks without telemetry and produces a score from 0 to 100.
claude mcp add checker-mcp -- npx -y @oksigenia/checker-mcpWhat checker-mcp does
The server operates entirely over stdio on your machine. Network calls hit only the target domain over HTTPS, Cloudflare DoH rather than Google resolvers, the HSTS preload registry, and rdap.org for registration records. It keeps your activity private by bypassing third-party scoring services.
Seventeen checks cover four areas: SSL certificates, mail verification (SPF, DKIM, DMARC, MTA-STS, BIMI), DNS records, and HTTP security headers. Each failed test comes with a concrete fix step. You can fetch output either as a formatted report or raw JSON.
Clients interact with three exposed tools: check_domain, list_checks, and explain_check. Node.js with npx is required to run the package directly, though a Docker container is also an option. If firewalls block outbound traffic to Cloudflare DoH or RDAP endpoints, domain reputation scans will fail.
What it helps with
- Inspect SSL certificate validity and expiration dates
- Audit email authentication records including SPF, DKIM, and DMARC
- Evaluate HTTP security headers such as CSP and HSTS
- Check domain status against known malware and phishing lists
Example prompts for the agent
- Check the security posture of example.com and show the report
- Explain the dmarc check and provide steps to fix issues
- List all available security checks with their explanations
How to install checker-mcp
Platform CLI
claude mcp add checker-mcp -- npx -y @oksigenia/checker-mcpPlatform CLI
codex mcp add checker-mcp -- npx -y @oksigenia/checker-mcpConfig file
{
"mcpServers": {
"checker-mcp": {
"command": "npx",
"args": [
"-y",
"@oksigenia/checker-mcp"
]
}
}
}Config file
{
"servers": {
"checker-mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@oksigenia/checker-mcp"
]
}
}
}Platform CLI
gemini mcp add checker-mcp npx -y @oksigenia/checker-mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about checker-mcp
How do I install checker-mcp in Claude Code?
Run claude mcp add checker-mcp -- npx -y @oksigenia/checker-mcp in your terminal. This registers the server via npx without manual configuration steps.
What does checker-mcp do?
It audits any domain across 17 security parameters, covering certificates, DNS records, email authentication, and HTTP headers. It assigns an overall score from 0 to 100 along with guidance on fixing failures.
What languages are supported for security reports?
Reports render in English or Spanish. You can choose the output language via the OKSIGENIA_LANG environment variable or specify it per tool request.
