Add AGENTS.md and CLAUDE.md for Cursor/Claude project rules

Introduce a single source of truth for agent guidance during the
planning-docs phase: document authority, tentative Q1-Q7 handling,
v1 scope guards, safety invariants, and next PoC priorities.

Co-authored-by: okuma <o0kuma@users.noreply.github.com>

AGENTS.md

@@ -0,0 +1,103 @@
+# Project Instructions — hikikomori / 분신 (가칭)
+
+This repository is currently a **planning-docs repo** for an AI-twin messenger
+("나를 대신해 남과 대화하는 AI 분신"). There is no application code yet.
+
+Canonical docs live under `docs/`. Prefer linking to them over copying content
+into prompts or new files.
+
+## Document authority
+
+When documents disagree, follow this order:
+
+1. [`docs/decision-log.md`](docs/decision-log.md) — working assumptions for Q1~Q7
+2. [`docs/vision.md`](docs/vision.md) / [`docs/PRD.md`](docs/PRD.md) / [`docs/tech-design.md`](docs/tech-design.md)
+3. [`docs/roadmap.md`](docs/roadmap.md) / [`docs/risk-log.md`](docs/risk-log.md)
+4. [`docs/PLANNING.md`](docs/PLANNING.md) — process guide
+5. [`docs/idea-meeting-2026-06-29.html`](docs/idea-meeting-2026-06-29.html) — historical meeting source only
+
+Notes:
+
+- Q1~Q7 in `decision-log.md` are **제안 (tentative)**, not final meeting
+  decisions. Do not silently reverse them. If a change is required, update
+  `decision-log.md` and all derived docs in the same change.
+- `PLANNING.md` §2 may still show empty checkboxes (`☐`). That is stale
+  template state — prefer `decision-log.md` for current working answers.
+- Stale wording such as “OS 레이어 → 자체 앱” is wrong. The working order is
+  **자체 앱 클로즈드 베타 first → OS 레이어 later** (`decision-log.md` Q7).
+
+## Product identity (v1 working assumptions)
+
+- Name (working): **분신**
+- One-liner: ChatGPT talks *with* me; 분신 talks *as* me *to others*
+- Target: consumer individuals first (not B2B)
+- Delivery: self-owned messenger, closed beta
+- Autonomy for v1: **L0~L2 only**
+- MVP scenarios: **읽씹 종결** + **단톡 따라잡기**
+- Platform: Android first
+
+## Hard scope guards (do not expand without an explicit decision-log update)
+
+Out of v1 scope:
+
+- L3 full away-mode auto-reply
+- L4 twin-to-twin negotiation / appointment auto-finalization
+- OS-layer bridging over KakaoTalk / Instagram / etc.
+- B2B / workspace products
+- Server-side full conversation analytics that violate on-device-first
+
+Do not design or implement Phase 2+ work before Phase 1 gates are validated
+(`docs/roadmap.md`).
+
+## Absolute safety invariants
+
+These apply at every autonomy level and must not be weakened for convenience:
+
+- Money, appointment confirmation, and emotional/sensitive topics always
+  escalate to the human. When uncertain, escalate (fail-safe).
+- Twin-authored messages must be visually distinct (badge / `sender_mode`).
+- Honest identity answers: if asked “본인이야 분신이야?”, answer as twin.
+- Peer veto: if the other person rejects the twin, disable auto-reply for that
+  conversation immediately.
+- Every automatic action needs post-hoc notification + one-tap undo.
+
+## Privacy & architecture principles
+
+- Tone/style learning: **on-device first**. Do not default to uploading raw chat
+  history to servers.
+- Autonomy / escalation engine: **client-side** so safety is not blocked by
+  server latency or outage.
+- Draft generation: on-device first, server LLM fallback with minimal context.
+- Relay/storage server is allowed; it is not a license for full cloud analysis.
+
+## Process rules
+
+Follow `docs/PLANNING.md`: decide → narrow → validate → specify.
+
+Current next priorities (do not invent a full stack first):
+
+1. PoC #1 — on-device tone realism
+2. PoC #3 — impersonation / trust acceptance (badge, veto UX)
+3. Clickable prototype (badge + veto)
+4. Small user interviews
+5. Meeting review to promote Q1~Q7 from 제안 → 확정
+
+Do not invent frameworks, folder layouts, or CI conventions until real code
+exists. When code work starts, prefer Android-first changes aligned with
+`docs/tech-design.md` and keep L0~L2 + safety invariants intact.
+
+## Documentation conventions
+
+- Planning docs are written in **Korean**.
+- Keep decisions traceable with links to `decision-log.md` Q# and related files.
+- Preserve `idea-meeting-2026-06-29.html` as historical source material; do not
+  treat it as the live decision record.
+- When status changes, keep `PLANNING.md` §8, `roadmap.md`, and `risk-log.md`
+  in sync.
+- Prefer updating existing docs over creating parallel overlapping docs.
+
+## Communication with agents
+
+- Read the relevant docs before proposing product/tech changes.
+- Call out whether a suggestion is inside v1 scope or a future-phase idea.
+- If requirements are ambiguous, ask before expanding scope.

CLAUDE.md

@@ -0,0 +1,15 @@
+# Claude Code — hikikomori / 분신
+
+Follow the project instructions in [@AGENTS.md](./AGENTS.md).
+
+Quick context:
+
+- This repo is planning docs only (no app code yet).
+- Working product name: **분신** (tentative).
+- Source of working decisions: `docs/decision-log.md` (status: 제안).
+- v1 scope: self-app closed beta, L0~L2, 읽씹 종결 + 단톡 따라잡기, Android first.
+- Hard bans for v1: L3/L4, OS-layer over third-party messengers, B2B.
+- Never weaken escalation, twin badge, peer veto, or undo.
+
+Before changing product or technical direction, read `AGENTS.md` and the
+relevant files under `docs/`.

README.md

@@ -13,6 +13,11 @@
 - 리스크 로그: [`docs/risk-log.md`](./docs/risk-log.md)
 - 로드맵: [`docs/roadmap.md`](./docs/roadmap.md)
 
+## AI 에이전트 규칙
+
+- Cursor / 공통: [`AGENTS.md`](./AGENTS.md)
+- Claude Code 진입점: [`CLAUDE.md`](./CLAUDE.md)
+
 ## 현재 단계
 
 아이디어 발산 → 컨셉 심화 → 기획 문서 세트(Vision/PRD/기술설계/리스크/로드맵) 초안 작성까지 완료.