Developer documentation

Self-Hosted MCPGate

Last reviewed 31 August 2026

Self-Hosted MCPGate

MCPGate brings CAIN's policy enforcement, agent security verification, and auditable execution directly into your own infrastructure.

Deployment Model

CAIN is delivered in two deployment models with identical trust control logic:

CAIN Studio (https://cainstudio.online): Hosted AI infrastructure runtime and managed trust control plane.
MCPGate (https://mcpgate.online): Self-hosted AI infrastructure runtime and self-hosted enforcement boundary operating within your private VPC or on-premise network.

In the self-hosted model, all prompt traffic, agent tool calls, policy evaluations, and evidence records remain entirely within your security boundary.

Architecture

Autonomous AI Agent
        │
        ▼ (Tool Call / Consequential Action)
┌──────────────────────────────────────────────┐
│ MCPGate Self-Hosted Enforcement Boundary     │
│                                              │
│  ├─ Moat #1: Trust State Engine              │
│  ├─ Moat #2: Security Context Continuity     │
│  ├─ Moat #3: Trust Graph Reachability        │
│  ├─ Moat #4: Execution Provenance            │
│  ├─ Moat #5: Predictive Trust & Blast Radius │
│  ├─ Moat #6: Adversarial Engine              │
│  └─ Moat #7: Autonomous Sentinel Control     │
└──────────────────────┬───────────────────────┘
                       │
       ┌───────────────┴───────────────┐
       ▼                               ▼
    ALLOW                           BLOCK
       │                               │
       ▼                               ▼
Downstream Tool / MCP Server    Execution Terminated
(Action Executed & Recorded)    (Evidence Preserved)

Prerequisites

Linux OS (Ubuntu 22.04+ / RHEL 9+ recommended)
Container Runtime: Docker Engine 24.0+ and Docker Compose v2, or Kubernetes 1.28+
Network: Local port 8000/8420 for enforcement boundary; no outbound internet required for air-gapped environments
Hardware: 2 CPU cores, 4 GB RAM minimum

Quickstart Deployment (Docker Compose)

1. Clone or download your licensed MCPGate bundle:

git clone https://github.com/cain-trust/mcpgate.git
cd mcpgate

2. Configure your environment:

cp .env.example .env
# Edit .env with your cluster secret and signing key parameters
chmod 0600 .env

3. Launch the enforcement boundary:

docker compose -f docker-compose.prod.yml up -d

4. Verify operational health:

curl -f http://localhost:8000/health

Expected output:

{"status": "healthy", "service": "platform-gateway"}

Air-Gapped & Fail-Closed Semantics

MCPGate operates under strict fail-closed security principles:

NO AUTHORIZATION → NO EXECUTION: An action is never permitted without explicit policy allowance.
UNKNOWN and ERROR never become ALLOW or TRUSTED: If a dependency, database, or policy service is unavailable or times out, the gate immediately returns BLOCK / DENY.
Tamper-Evident Evidence Chain: All decisions generate SHA-256 chained audit records stored in local SQLite or external WORM volumes.

Integration

Point your agent framework or MCP client directly to your local MCPGate instance:

from cain import trust

# Route consequential tool execution through your local boundary
@trust(gateway_url="http://localhost:8000", action="execute_query", resource="prod_db")
def run_query(sql: str):
    ...

Verifying Conformance

Run the built-in conformance suite against your local instance to verify all 7 moats:

cain test --runtime --mcp