diff --git a/mobile/README.md b/mobile/README.md
index bc11b3e..9c644bf 100644
--- a/mobile/README.md
+++ b/mobile/README.md
@@ -29,7 +29,20 @@ flutter run --dart-define=CORE_API_BASE=http://10.0.2.2:8080
 flutter run --dart-define=CORE_API_BASE=http://<your-lan-ip>:8080
 ```
 
-## E2E 수동 QA 체크 (에뮬레이터/실기기)
+## E2E
+
+**API 레벨 (클라우드/CI에서 실행 가능)**
+
+```bash
+# core-backend :8080 + ai-service :8001 기동 후
+export ADMIN_API_TOKEN=dev-admin-token
+python3 scripts/e2e_a3.py
+```
+
+A3 체크리스트(가입·연락처·대화·히스토리·draft/L1·에스컬레이션·되돌리기·거부권·화이트리스트)를
+HTTP로 검증한다.
+
+**에뮬레이터/실기기 UI 탭 (Android SDK 필요)**
 
 1. 초대 코드로 가입 → 말투 샘플 저장(또는 나중에)
 2. 연락처에 상대 사용자 ID 등록 → 대화 시작
diff --git a/scripts/e2e_a3.py b/scripts/e2e_a3.py
new file mode 100755
index 0000000..d742bb1
--- /dev/null
+++ b/scripts/e2e_a3.py
@@ -0,0 +1,197 @@
+#!/usr/bin/env python3
+"""A3 API-level E2E against a running core-backend (+ ai-service for draft/escalate).
+
+Covers mobile/README.md checklist at the HTTP layer.
+Android emulator/device UI taps are out of scope in this cloud VM (no Android SDK).
+"""
+from __future__ import annotations
+
+import json
+import os
+import sys
+import urllib.error
+import urllib.request
+
+BASE = os.environ.get("CORE_API_BASE", "http://127.0.0.1:8080")
+ADMIN = os.environ.get("ADMIN_API_TOKEN", "dev-admin-token")
+
+passed = 0
+failed = 0
+
+
+def ok(msg: str) -> None:
+    global passed
+    passed += 1
+    print(f"  OK: {msg}")
+
+
+def fail(msg: str) -> None:
+    global failed
+    failed += 1
+    print(f"  FAIL: {msg}")
+
+
+def step(msg: str) -> None:
+    print(f"\n==> {msg}")
+
+
+def req(method: str, path: str, body=None, token: str | None = None, admin: bool = False):
+    data = None if body is None else json.dumps(body).encode()
+    headers = {"Content-Type": "application/json"}
+    if admin:
+        headers["Authorization"] = f"Bearer {ADMIN}"
+    elif token:
+        headers["Authorization"] = f"Bearer {token}"
+    request = urllib.request.Request(BASE + path, data=data, headers=headers, method=method)
+    try:
+        with urllib.request.urlopen(request) as resp:
+            raw = resp.read().decode()
+            return resp.status, json.loads(raw) if raw else {}
+    except urllib.error.HTTPError as e:
+        raw = e.read().decode()
+        try:
+            payload = json.loads(raw) if raw else {}
+        except json.JSONDecodeError:
+            payload = {"raw": raw}
+        return e.code, payload
+
+
+def main() -> int:
+    step("health")
+    code, body = req("GET", "/health")
+    ok("core health") if code == 200 else fail(f"health {code} {body}")
+
+    step("1) invite + signup (two users)")
+    _, ia = req("POST", "/invites", {}, admin=True)
+    _, ib = req("POST", "/invites", {}, admin=True)
+    code_a, sa = req("POST", "/auth/signup", {"invite_code": ia["code"], "display_name": "E2E Alice"})
+    code_b, sb = req("POST", "/auth/signup", {"invite_code": ib["code"], "display_name": "E2E Bob"})
+    if code_a == 200 and code_b == 200 and sa.get("token") and sb.get("token"):
+        ok(f"signup tokens for #{sa['id']} and #{sb['id']}")
+    else:
+        fail(f"signup a={code_a} b={code_b}")
+        return 1
+    token_a, token_b = sa["token"], sb["token"]
+    id_a, id_b = sa["id"], sb["id"]
+
+    step("2) contact + conversation create")
+    _, contact = req(
+        "POST",
+        f"/users/{id_a}/contacts",
+        {"display_name": "Bob", "contact_user_id": id_b, "relationship_note": "e2e"},
+        token=token_a,
+    )
+    contact_id = contact["id"]
+    _, conv = req(
+        "POST",
+        "/conversations",
+        {"user_ids": [id_a, id_b], "contact_id": contact_id},
+        token=token_a,
+    )
+    conv_id = conv["id"]
+    ok(f"conversation #{conv_id} via contact #{contact_id}")
+    _, clist = req("GET", "/conversations", token=token_a)
+    ids = [c["id"] for c in clist.get("conversations", [])]
+    ok("conversation list includes room") if conv_id in ids else fail(f"list missing room: {ids}")
+
+    step("3) human message + history")
+    _, msg = req(
+        "POST",
+        f"/conversations/{conv_id}/messages",
+        {"sender_id": id_a, "text": "안녕 Bob", "sender_mode": "human"},
+        token=token_a,
+    )
+    msg_id = msg["id"]
+    _, hist = req("GET", f"/conversations/{conv_id}/messages", token=token_a)
+    hist_ids = [m["id"] for m in hist.get("messages", [])]
+    ok(f"history retains message #{msg_id}") if msg_id in hist_ids else fail("history")
+
+    step("4) draft + L1 approved twin send")
+    dcode, draft = req(
+        "POST",
+        f"/conversations/{conv_id}/draft",
+        {"context_lines": ["상대: 오늘 뭐해?"], "style_examples": ["ㅇㅇ 알겠음", "ㅋㅋ 그래"]},
+        token=token_a,
+    )
+    if dcode == 200 and draft.get("status") in {"ok", "no_key", "escalate"}:
+        ok(f"draft status={draft.get('status')}")
+    else:
+        fail(f"draft {dcode} {draft}")
+    req("PATCH", f"/users/{id_a}/twin-settings", {"autonomy_level": "L1"}, token=token_a)
+    twin_text = "ㅇㅇ 알겠음 나중에"
+    if draft.get("status") == "ok" and draft.get("text"):
+        twin_text = draft["text"]
+    tcode, twin = req(
+        "POST",
+        f"/conversations/{conv_id}/messages",
+        {"sender_id": id_a, "text": twin_text, "sender_mode": "twin", "approved": True},
+        token=token_a,
+    )
+    twin_id = twin.get("id")
+    if tcode == 200 and twin_id:
+        ok(f"L1 approved twin message #{twin_id}")
+    else:
+        fail(f"twin send {tcode} {twin}")
+        return 1
+
+    step("5) escalation path + inbox logs")
+    ecode, _ = req(
+        "POST",
+        f"/conversations/{conv_id}/messages",
+        {
+            "sender_id": id_a,
+            "text": "계좌로 돈 보내줄게 계좌번호 알려줘",
+            "sender_mode": "twin",
+            "approved": True,
+        },
+        token=token_a,
+    )
+    if ecode != 200:
+        ok(f"escalating twin blocked (HTTP {ecode})")
+    else:
+        fail("escalating twin unexpectedly accepted")
+    _, logs = req("GET", f"/users/{id_a}/escalation-logs", token=token_a)
+    if "escalation_logs" in logs:
+        ok(f"escalation-logs count={len(logs['escalation_logs'])}")
+    else:
+        fail("escalation-logs shape")
+
+    step("6) retract twin + veto")
+    rcode, _ = req("POST", f"/messages/{twin_id}/retract", token=token_a)
+    ok(f"retract HTTP {rcode}") if rcode == 200 else fail(f"retract {rcode}")
+    vcode, _ = req("POST", f"/conversations/{conv_id}/veto", token=token_b)
+    ok(f"peer veto HTTP {vcode}") if vcode == 200 else fail(f"veto {vcode}")
+    bcode, _ = req(
+        "POST",
+        f"/conversations/{conv_id}/messages",
+        {"sender_id": id_a, "text": "veto 이후", "sender_mode": "twin", "approved": True},
+        token=token_a,
+    )
+    ok(f"twin blocked after veto (HTTP {bcode})") if bcode != 200 else fail("twin allowed after veto")
+
+    step("7) whitelist CRUD + autonomy")
+    _, wl = req(
+        "POST",
+        f"/users/{id_a}/whitelist-rules",
+        {"topic_keyword": "날씨"},
+        token=token_a,
+    )
+    _, wlist = req("GET", f"/users/{id_a}/whitelist-rules", token=token_a)
+    rules = wlist.get("whitelist_rules", [])
+    ok("whitelist add/list") if any(r.get("topic_keyword") == "날씨" for r in rules) else fail("whitelist")
+    dcode, _ = req("DELETE", f"/users/{id_a}/whitelist-rules/{wl['id']}", token=token_a)
+    ok("whitelist delete") if dcode == 200 else fail(f"whitelist delete {dcode}")
+    acode, _ = req("PATCH", f"/users/{id_a}/twin-settings", {"autonomy_level": "L0"}, token=token_a)
+    ok("autonomy L0 reset") if acode == 200 else fail(f"autonomy {acode}")
+
+    step("8) contacts list")
+    _, contacts = req("GET", f"/users/{id_a}/contacts", token=token_a)
+    cids = [c["id"] for c in contacts.get("contacts", [])]
+    ok("contacts list") if contact_id in cids else fail("contacts list")
+
+    print(f"\n==== E2E RESULT: {passed} passed, {failed} failed ====")
+    return 0 if failed == 0 else 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())