# email_domain_health_check

Comprehensive email domain health check: MX routing, SPF authentication, DKIM signing, DMARC policy enforcement, DNSBL blacklist status (Spamhaus/SpamCop/Barracuda), TLS certificate validity, and WHOIS registration age. Aggregates a reputation score 0-100 and generates P0/P1/P2 deliverability signals. Accepts a domain (stripe.com) or email address (info@stripe.com). Detects role-based addresses (info@, support@, admin@, noreply@) that have higher bounce rates. Detects email provider (Google Workspace, Microsoft 365, Amazon SES, etc.). P0 signals: blacklisted / no MX / TLS expired / no SPF + DMARC none. P1 signals: SPF soft-fail / no DKIM selector / DMARC no reporting. P2 signals: role-based address / TLS expires <30d / domain age <90 days. All checks are keyless (no API keys required). Cache TTL 1h. SLA <=10s p95.

Agent View of the PolicyLayer registry record for `email_domain_health_check`. HTML page: https://policylayer.com/tools/io-github-getgapup-gapup-mcp/email-domain-health-check

## Facts

- Tool: `email_domain_health_check`
- Server: Gapup Mcp (`https://mcp.gapup.io/mcp`) — https://policylayer.com/tools/io-github-getgapup-gapup-mcp.md
- Homepage: https://github.com/getgapup/gapup-mcp-public
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server rate-limited: no
- Parameters: 4 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `async` | boolean | no | If true, returns a job_id immediately (<200ms) instead of waiting for the result. Poll the result with job_result(job_id). Use for slow tools to avoid client ti |
| `email` | string | no | Full email address for additional checks: format validity, role-based detection (e.g. "ceo@stripe.com"). |
| `checks` | array | no | Subset of checks to run. Defaults to all 8: ["mx","spf","dkim","dmarc","blacklist","whois","tls","reputation"]. Use a subset for faster responses (e.g. ["mx","s |
| `domain` | string | yes | Domain to check (e.g. "stripe.com" or "@stripe.com"). If an email address is provided here, the domain is extracted automatically. |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

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

## Why email_domain_health_check is rated Low

This is a reconnaissance and diagnostic tool that queries infrastructure and third-party services (DNS, DNSBL, WHOIS) to assess email domain health. While the output could be misused for targeting or phishing validation, the tool itself only reads and aggregates publicly available or standard protocol information.

From the tool's own definition: "Tool performs DNS queries, DNSBL lookups, WHOIS registration checks, and email authentication verification (MX, SPF, DKIM, DMARC, TLS). Description explicitly states it 'checks', 'detects', 'aggregates', and 'generates signals'—all read-only operations."

Risk signals: Admin/system-level operation

## Use case

AI agents call email_domain_health_check to retrieve information from Gapup Mcp without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Gapup Mcp:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "email_domain_health_check": {}
  }
}
```

## Other tools on Gapup Mcp (270)

- `adversarial_input_stress_tester` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/adversarial-input-stress-tester.md
- `dora_operational_resilience_stress_tes` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/dora-operational-resilience-stress-tes.md
- `financial_model_3statement` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/financial-model-3statement.md
- `gl_reconciler` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/gl-reconciler.md
- `lgpd_data_subject_rights_automator` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/lgpd-data-subject-rights-automator.md
- `monte_carlo_portfolio` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/monte-carlo-portfolio.md
- `process_mining` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/process-mining.md
- `ugc_moderation_classifier` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/ugc-moderation-classifier.md
- `workflow_orchestrator` — Execute — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/workflow-orchestrator.md
- `abm_architect` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/abm-architect.md
- `account_expansion_mapper` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/account-expansion-mapper.md
- `anti_demissions_hr` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/anti-demissions-hr.md
- `audit_pre_flight` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/audit-pre-flight.md
- `budget_variance_ai` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/budget-variance-ai.md
- `capacity_planning` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/capacity-planning.md
- `capital_strategy` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/capital-strategy.md
- `churn_defender` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/churn-defender.md
- `competitor_moves` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/competitor-moves.md
- `competitor_recommendations` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/competitor-recommendations.md
- `content_engine` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/content-engine.md
- `cross_sell_reco` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/cross-sell-reco.md
- `customer_voice_synth` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/customer-voice-synth.md
- `cyber_risk_auditor` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/cyber-risk-auditor.md
- `deal_structurer` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/deal-structurer.md
- `discovery_prep` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/discovery-prep.md
- `diversity_inclusion_metrics` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/diversity-inclusion-metrics.md
- `earnings_reviewer` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/earnings-reviewer.md
- `enps_auto` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/enps-auto.md
- `event_marketing` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/event-marketing.md
- `fraud_detector` — Financial — https://policylayer.com/tools/io-github-getgapup-gapup-mcp/fraud-detector.md
- …and 240 more: https://policylayer.com/tools/io-github-getgapup-gapup-mcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-getgapup-gapup-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-getgapup-gapup-mcp