MCP Security Gateway
An MCP security gateway answers the question every team hits once AI agents touch real systems: what is this thing actually allowed to do — and can we prove what it did? It sits between your AI clients and your MCP servers, and every tool call passes through enforcement first: authentication, per-tool policy, data-loss prevention, behavioral scoring, and audit.
Get started freeWhy per-call security isn't optional
MCP servers execute whatever a model asks, with whatever credentials they hold. The model, in turn, does whatever its context persuades it to do — and context includes untrusted document text, web content, and tool results. Without an enforcement layer between them, your security boundary is the model's judgment on its worst day. A security gateway replaces that hope with rules that hold even when the model is confused, manipulated, or looping.
Threat → control mapping
Unauthenticated or over-broad access
Every endpoint requires a slug-scoped bearer token; tokens expire and rotate; servers can be disabled at the gateway instantly.
Secure an existing remote server →Secrets & PII leaving through tool traffic
DLP scans tool arguments and JSON results with monitor, redact, and block modes, plus org-specific custom rules. Audit records store rule classes, never the matched secret.
Protect sensitive data →Excessive agency & destructive operations
Per-tool policies (allow / audit / approve / deny), destructive shell-command blocking, and human-in-the-loop approval with Slack alerts.
Control which tools may run →Attack sequences that pass per-call checks
Tool-order rules (prerequisites per session) and a rolling session risk score with monitor and enforce modes catch the pattern, not just the call.
Session risk scoring →Malformed & manipulated arguments
Input contracts validate every tools/call against the tool's declared JSON Schema; payload size, depth, and structure caps reject abuse before parsing gets expensive.
Validate tool arguments →Floods, loops & unbounded consumption
Token-bucket rate limits per server, request/response size limits, and budgets keep a runaway agent bounded.
Rate-limit tool calls →“We think nothing bad happened”
A structured audit log of every call — arguments (scrubbed), results, statuses, correlation IDs, approvals, and policy decisions — queryable per server and per session.
MCP audit logging guide →For the deeper honest-scope discussion — including what a gateway can and cannot do about model-side risks — see how Guardian maps MCP threats to real controls.
Designed to be turned on gradually
Security tooling fails when it blocks the team on day one. Every enforcement feature here has a watch-first mode: DLP runs in monitor before it redacts, session risk logs before it denies, and a per-server Observe-only posture records every would-be policy decision without enforcing any of them. You see exactly what a policy would have done to last week's real traffic before it can block anyone.
Five minutes to enforced
- Create a free account at app.mcptrail.com
- Route a server through the gateway — hosted from the marketplace or your existing server by URL
- Point clients at the new endpoint (Claude, Cursor, VS Code snippets)
- Open the server's Security tab and switch on the controls above, monitor-first
Frequently asked questions
What is an MCP security gateway?
An MCP security gateway is a policy-enforcement proxy for Model Context Protocol traffic. It terminates MCP from AI clients, authenticates every request, and applies security controls — tool policies, DLP, human approvals, rate limits, argument validation, and audit logging — before traffic reaches your MCP servers.
How is a security gateway different from a plain MCP gateway?
A plain gateway routes and aggregates. A security gateway makes enforcement the core: every tool call is checked against policies, scanned for sensitive data, scored for behavioral risk, and recorded for audit. Routing is table stakes; the security layer is the product.
Does it protect against prompt injection?
It limits what injection can achieve. The gateway can't stop untrusted text from reaching the model, but it decides what a manipulated model may execute: denied tools stay denied, risky calls wait for human approval, argument contracts reject smuggled payloads, and sequence and risk rules catch escalation patterns.
Do I have to change my MCP servers?
No. The gateway fronts your servers' existing endpoints — clients switch to the gateway URL and everything else stays the same. Hosted, remote, and self-hosted servers are all supported.
Is there a self-hosted option?
Yes. MCP Trail ships a self-hosted edition for teams whose tool traffic can't leave their own infrastructure.