Fulcrum Container Map (C4 Level 2)

Shows all services/containers and their connections

Last Updated: January 15, 2026

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Container Diagram

graph TB
    subgraph Clients["Client Layer"]
        MCP["MCP Server<br/>(JSON-RPC 2.0)"]
        SDK_PY["Python SDK<br/>fulcrum-governance"]
        SDK_TS["TypeScript SDK<br/>@fulcrum-governance/sdk"]
        CLI["CLI<br/>fulcrum"]
        DASH["Dashboard<br/>Next.js 14"]
    end

    subgraph Backend["Backend Services"]
        API["REST API<br/>:8080"]
        GRPC["gRPC Server<br/>:50051"]

        subgraph Core["Core Services"]
            PE["Policy Engine<br/><10ms P99"]
            CE["Cost Engine<br/>Budget tracking"]
            ES["Event Store<br/>NATS publisher"]
        end

        subgraph Cognitive["Cognitive Layer"]
            SJ["Semantic Judge<br/>Intent analysis"]
            OR["Oracle<br/>Cost prediction"]
            IS["Immune System<br/>Auto-policy gen"]
        end
    end

    subgraph Data["Data Layer"]
        PG[("PostgreSQL 16<br/>+ TimescaleDB<br/>:5432")]
        RD[("Redis 7<br/>:6379")]
        NATS[("NATS JetStream<br/>:4222")]
        OL["Ollama<br/>llama3.2<br/>:11434"]
    end

    subgraph External["External Services"]
        CLERK["Clerk<br/>Authentication"]
        STRIPE["Stripe<br/>Billing"]
    end

    MCP --> API
    SDK_PY --> API
    SDK_PY --> GRPC
    SDK_TS --> API
    SDK_TS --> GRPC
    CLI --> API
    DASH --> API
    DASH --> CLERK

    API --> PE
    API --> CE
    API --> ES
    GRPC --> PE
    GRPC --> CE

    PE --> SJ
    PE --> RD
    CE --> OR
    ES --> NATS

    SJ --> OL
    OR --> PG

    PE --> PG
    CE --> PG
    ES --> PG

    API --> STRIPE

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Container Details

Client Containers

Container	Technology	Port	Purpose
MCP Server	Go	8080	AI agent self-governance via JSON-RPC
Python SDK	Python 3.9+	-	Client library for Python apps
TypeScript SDK	TypeScript	-	Client library for Node/browser
CLI	Go	-	Automation and GitOps workflows
Dashboard	Next.js 14	3000	Admin UI for humans

Backend Containers

Container	Technology	Port	Latency Target
REST API	Go + Chi	8080	<50ms P99
gRPC Server	Go + gRPC	50051	<20ms P99
Policy Engine	Go	internal	<10ms P99
Cost Engine	Go	internal	<20ms P99
Event Store	Go + NATS	internal	<5ms P99

Cognitive Containers

Container	Technology	Port	Latency Target
Semantic Judge	Go + Ollama	internal	<50ms P99
Oracle	Go + ML	internal	<20ms P99
Immune System	Go	internal	Async

Data Containers

Container	Technology	Port	Purpose
PostgreSQL	PostgreSQL 16	5432	Primary state, RLS multi-tenancy
TimescaleDB	TimescaleDB 2.x	5432	Time-series metrics
Redis	Redis 7	6379	Policy cache, rate limits
NATS JetStream	NATS 2.x	4222	Durable event streaming
Ollama	Ollama	11434	Local LLM inference

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Communication Patterns

Synchronous (Request/Response)

• REST API ↔ Clients (HTTP/JSON)
• gRPC ↔ SDKs (Protobuf)
• Policy Engine ↔ Redis (TCP)
• All services ↔ PostgreSQL (TCP)

Asynchronous (Events)

• Event Store → NATS JetStream (Publish)
• Consumers ← NATS JetStream (Subscribe)
• Dashboard ← WebSocket (Real-time updates)

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Multi-Tenancy Boundaries

┌─────────────────────────────────────────────────────┐
│                   Tenant A                           │
│  ┌─────────────────────────────────────────────────┐│
│  │ PostgreSQL: RLS WHERE tenant_id = 'A'           ││
│  │ Redis: Keys prefixed with tenant:A:*            ││
│  │ NATS: Subject prefix fulcrum.A.*                ││
│  └─────────────────────────────────────────────────┘│
└─────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────┐
│                   Tenant B                           │
│  ┌─────────────────────────────────────────────────┐│
│  │ PostgreSQL: RLS WHERE tenant_id = 'B'           ││
│  │ Redis: Keys prefixed with tenant:B:*            ││
│  │ NATS: Subject prefix fulcrum.B.*                ││
│  └─────────────────────────────────────────────────┘│
└─────────────────────────────────────────────────────┘

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