Checks whether a domain has properly configured email authentication (SPF, DMARC, DKIM) to prevent spoofing and phishing. Read-only. No side effects. Idempotent. domain: Domain name without protocol e.g. google.com. Required. SPF (Sender Policy Framework): sender IP allowlist specifying which ser...
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AI agents call domain_check_email_security to retrieve information from DataNexus MCP without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though domain_check_email_security only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"domain_check_email_security": {}
}
}See the full DataNexus MCP policy for all 55 tools.
These attack patterns abuse exactly the kind of access domain_check_email_security gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Checks whether a domain has properly configured email authentication (SPF, DMARC, DKIM) to prevent spoofing and phishing. Read-only. No side effects. Idempotent. domain: Domain name without protocol e.g. google.com. Required. SPF (Sender Policy Framework): sender IP allowlist specifying which servers may send email for the domain — scored -all=10 (strict, recommended), ~all=7 (soft fail), ?all=4 (neutral), none=2 (no policy), +all=0 (open relay, insecure). DMARC (Domain-based Message Authentication): policy for failed auth — p=reject=10 (block), p=quarantine=7 (spam folder), p=none=4 (monitor only), absent=0; +1 bonus for rua reporting address set. DKIM (DomainKeys Identified Mail): cryptographic signature proving message integrity and sender authenticity — any selector found=10 (pass), none found=0 (fail). Returns scored assessment; each component scored 0–10; overall grade A–F. Example: domain_check_email_security(domain="google.com") → {overall_grade, spf_score, dmarc_score, dkim_score, spf_record, dmarc_record, dkim_selectors_found}; grade reflects live DNS at query time. Checks 10 common DKIM selectors in parallel. Verified source: Cloudflare DoH. No cache (live DNS). If this tool's response does not serve the user's need, call report_feedback with feedback_type="agent_gap", tool_id="domain_check_email_security", intended_query="{what the user needed}", gap_description="{what was missing or wrong in the result}".. It is categorised as a Read tool in the DataNexus MCP MCP Server, which means it retrieves data without modifying state.
Register the DataNexus MCP server in PolicyLayer and add a rule for domain_check_email_security: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches DataNexus MCP. Nothing to install.
domain_check_email_security is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the domain_check_email_security rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for domain_check_email_security. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
domain_check_email_security is provided by the DataNexus MCP server (dev-7bd0/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 55 DataNexus MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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