Nunchi Bridge

Alexa+ relays messages between family members who don't share a language — in the register their relationship requires — and turns replies into plans both sides confirm.

Built for the Amazon Developer Hackathon 2026 (Alexa+ track) as a self-hosted MCP server (MCP spec 2025-11-25, Streamable HTTP) plus a simulated Alexa+ household web app. It does not run on a real Echo: Alexa+ add-on developer tools are in partner-only preview.

Demo video (1:37): https://youtu.be/MXJBo56_VDk — playback of a recorded live run; MCP calls, register checks and saves executed for real; AI text-to-speech narration.

What it does

1. Minjun (English) says: "Tell grandma I can't make it Sunday. Something came up."

2. The host agent looks up the household (get_household): grandson → grandmother requires polite Korean (해요체).

3. For comparison, a generic translation with no family context (a recorded Gemini output: 할머니한테 일요일에 못 간다고 전해줘. 일이 생겼어.) is refused by check_register: plain endings are curt from a grandchild to a grandmother. send_message would refuse it too, whatever the LLM wants. It is never sent.

4. The agent's own relationship-aware draft passes the gate and is delivered. Minjun hears a back-translation to confirm the meaning.

5. Halmeoni replies in Korean: 그럼 토요일에 와. 갈비찜 해놓을게. 김치통 꼭 가져오고.

6. Minjun gets it in English. The agent calls propose_plan, and each item must quote its evidence verbatim from her message. Nothing is scheduled yet.

7. Minjun presses Confirm, and commit_plan stores the Saturday visit and "bring the kimchi container" in shared state.

Related MCP server: OpenFateAI Assistant MCP

What the register gate is, and is not

It is: a deterministic safety gate, separate from the LLM, that catches selected high-risk Korean register violations before a message is sent. It checks three things:

• plain (반말) sentence endings;

• plain or confrontational "you" (너/너희/당신);

• a few honorific-vocabulary slips. These are soft hints and do not block.

It is not: a complete judge of Korean politeness. Known limits (clause-level plain speech, subject honorifics, context-dependent 당신, family norms) are listed in docs/LINTER_RED_TEAM.md. Native-speaker review results are in docs/register_eval_set_reviewed.csv and summarized in the red-team doc; no general accuracy figure is claimed.

Family setting: the family's norm, not a textbook rule

By default, grandson → grandmother requires polite Korean. Some close families text their grandparents in casual speech (반말), and for them a refusal would be wrong. So a person can switch a pair to casual allowed (the toggle in the simulator header; POST /household/settings on the server).

• This is not an MCP tool. An agent must never be able to relax the gate it is checked by.

• Even in a casual family, plain/confrontational "you" (너, 당신) toward an elder is still refused.

• Formal (하십시오체) or archaic endings are never blocked. They get a non-blocking warning with a suggested 해요체 replacement, e.g. 연락드리겠습니다 → 연락드릴게요, 잡수셨사옵니까? → 드셨어요?. The suggestion is only offered when a safe rule applies; irregular stems get no guess.

Implemented vs. simulated

Run it

pip install -r requirements.txt -c constraints-windows.txt   # Python 3.11+; pins MCP SDK v1 (2.x removed FastMCP)
python -m nunchi.server                   # MCP server  -> http://127.0.0.1:8000/mcp
python -m nunchi.sim_app                  # simulator   -> http://127.0.0.1:8080
# optional live mode:
GEMINI_API_KEY=... python -m nunchi.sim_app
# optional fixed demo date (weekday resolution): NUNCHI_TODAY=2026-10-07 python -m nunchi.server

On Windows PowerShell, see the Windows first-run guide. Do not enable billing for this demo; check current Gemini free-tier model availability before choosing GEMINI_MODEL.

Recorded live demo

In live mode the simulator records responses (tool arguments, translations, final replies) to live-recordings/latest-live-run.json, and archives a copy after confirmation. API keys and HTTP headers are not recorded. After one clean grandchild → grandmother → confirm flow:

python -m nunchi.recording --input live-recordings/successful-live-run.json --output nunchi/replay/demo_script.json

The converter rejects incomplete, failed or unconfirmed runs. Only the proposal's message ID and next-Saturday date become placeholders. Replay accepts only the recorded inputs (use Use demo line); start the server with NUNCHI_TODAY=2026-09-30 to reproduce the recorded dates exactly. See VALIDATION_V3_KO.md. LIVE_RUN_REPORT_KO.md is the earlier run's historical report.

Tests: python -m unittest discover -s tests (unit, MCP-over-HTTP integration, end-to-end demo scenario). Any MCP client works against the server, for example MCP Inspector with transport "Streamable HTTP" and URL http://127.0.0.1:8000/mcp.

Tools

The demo reset is an HTTP route (POST /demo/reset), deliberately not an MCP tool. The host also blocks any LLM attempt to call commit_plan.

Data and privacy

The household is fictional. State is in memory only.

License

MIT (see LICENSE).