Northbridge Home Ops

Amazon Developer Hackathon 2026 submission — self-hosted MCP server (Streamable HTTP, MCP 2025-11-25+) for Alexa+, plus a polished web simulator.

Quiet household admin for the fictional Northbridge home (Avery & Morgan Quinn): bills, calendar dues, funding checks, and escalate-only decisions. Routine work stays silent; humans are pinged only when policy says HUMAN_REQUIRED.

Demo video

https://youtu.be/QTPBWsWi7vg

Related MCP server: VaultAlexa+

Live demo

Public Control Plane / Alexa+ simulator: https://northbridge-alexa-mcp.vercel.app

Same fixture household (Avery & Morgan Quinn), policy, and tool scenarios as the local MCP server — use Run quiet pass, ask “What's due this week?”, or escalate StreamFlix / dental / PG&E. No AWS keys required.

Why this wins the brief

Judge quickstart (offline, ~60 seconds)

git clone https://github.com/dl88jing/northbridge-alexa-mcp.git
cd northbridge-alexa-mcp
./demo.sh

Expected highlights:

• AUTO: PG&E (in-band), Cascadia Fiber, Rent

• HUMAN_REQUIRED: StreamFlix (amount jump), PG&E duplicate, Bayview Dental (medical)

Full interactive demo (MCP + web sim)

# Terminal 1 — MCP Control Plane
./demo.sh serve

# Terminal 2 — Alexa+ web simulator
./demo.sh web

Open http://127.0.0.1:5173 — ask “What's due this week?” or click Run quiet pass.

Or one process pair: ./demo.sh all

Product story

Avery and Morgan do not want another dashboard. They want Northbridge to:

1. See what is due

2. Check funding against reserve floors

3. Detect anomalies (unexpected amounts, duplicates, sensitive categories)

4. Auto-handle the boring safe bills

5. Escalate once, with a speakable brief, when a real decision is required

That is the Alexa+ experience: a short conversation backed by durable MCP tools and an auditable ledger.

Architecture

Alexa+  /  Web Simulator
        │  Streamable HTTP MCP (/mcp) + REST Control Plane (/api/*)
        ▼
northbridge.server (MCPServer)
        │
        ├─ Strands @tool functions (shared with Agent)
        ├─ Deterministic policy: AUTO vs HUMAN_REQUIRED
        ├─ Fixture household data under data/
        └─ Hash-chained audit ledger (data/runtime/audit_ledger.jsonl)

Strands Agents SDK
  • DemoModel  → offline judge path (no keys)
  • BedrockModel → live Amazon Bedrock path

Details: docs/architecture.md

MCP tools

Protocol: Streamable HTTP at http://127.0.0.1:8765/mcp (stateless JSON responses for easy local demos).

How Alexa+ is used

1. Northbridge runs as a self-hosted MCP server on Streamable HTTP.

2. Alexa+ connects to that MCP endpoint and discovers the tools above.

3. Utterances like “what’s due” or “handle the quiet pass” map to tool calls.

4. When policy returns HUMAN_REQUIRED, notify_human produces speakable copy Alexa+ can read back — no dashboard babysitting.

The Vite/React app is a faithful simulator of that loop for judges without device access: same tools, same policy, same ledger.

How AWS / Strands are used

• Every tool is a Strands Agents SDK @tool callable — one implementation shared by MCP registration and Agent(tools=...).

• Offline (default): DemoModel + deterministic run_offline_pipeline() — zero cloud credentials.

• Live Bedrock:

export AWS_REGION=us-west-2
export NORTHBRIDGE_USE_BEDROCK=1
# plus standard AWS credentials with Bedrock access
python -c "from northbridge.agent import run_with_strands_agent; print(run_with_strands_agent())"

Optional: pip install -e '.[bedrock]' for boto3.

Project layout

northbridge/           # MCP server, tools, policy, ledger, DemoModel, Strands agent
web/                   # Vite + React Alexa+ / Control Plane simulator
data/                  # Fixture household, bills, dues, funding, policy
docs/architecture.md   # System design
demo.sh                # One-command offline demo (+ serve/web/all)
LICENSE                # Apache-2.0

Manual install

python3 -m venv .venv && source .venv/bin/activate
pip install -e .
python -m northbridge.demo          # offline pipeline
python -m northbridge.server        # MCP + /api on :8765

cd web && npm install && npm run dev

Fixture household (fictional)

• Northbridge residence — Avery Quinn (ops primary) & Morgan Quinn (ops secondary)

• Joint checking with reserve floor, HSA, emergency savings

• Mixed dues engineered to exercise AUTO and HUMAN_REQUIRED paths

License

Apache License 2.0 — see LICENSE.

Hackathon track

Amazon Developer Hackathon 2026 — Alexa+ with self-hosted MCP, AWS Builder story via Strands Agents SDK + Amazon Bedrock.