diff --git a/M01_MasterData/M01_MasterData_Router.py b/M01_MasterData/M01_MasterData_Router.py
index 31501f7f8..de50a83e3 100644
--- a/M01_MasterData/M01_MasterData_Router.py
+++ b/M01_MasterData/M01_MasterData_Router.py
@@ -14,6 +14,7 @@ from pydantic import BaseModel
 
 from M01_MasterData import M01_MasterData_Store as store
 from M01_MasterData import M01_MasterData_Store_Combo as combo_store
+from M01_MasterData import M01_MasterData_Store_Flow as flow
 from M01_MasterData import M01_MasterData_Store_Make as make
 
 router = APIRouter(prefix="/api/m01", tags=["M01 MasterData"])
@@ -221,6 +222,10 @@ def get_materials(
 
 @router.post("/calc")
 def post_calc(body: CalcBody) -> dict:
+    """줄에 「흐름」 이 있으면 흐름 셈(입력 = 설계 때 정할 것) · 없으면 옛 셈(정함 4)."""
+    got = _call(flow.calc, body.key, body.inputs, body.row)
+    if got is not None:
+        return got
     with store.cm.mf.mp.choosing(body.고름):
         return _call(store.calc, body.key, body.inputs, body.row, body.file)
 
@@ -234,7 +239,14 @@ def post_text(body: CalcBody) -> dict:
 
 @router.post("/save")
 def post_save(body: SaveBody) -> dict:
-    return {"files": _call(store.save, [f.model_dump() for f in body.files])}
+    """「흐름」 줄은 검사 · 서버 다시 셈 · 새 줄(키 없음)은 자체 GX — {files, added, warnings}."""
+    return _call(flow.save, [f.model_dump() for f in body.files])
+
+
+@router.get("/logic/flow")
+def get_logic_flow(key: str, file: str = "") -> dict:
+    """흐름 받기 — {flow, converted, notes} · 흐름이 있으면 그대로 · 없으면 변환(파일 안 바뀜)."""
+    return _call(flow.get_flow, file, key)
 
 
 @router.post("/logic/new")
diff --git a/M01_MasterData/M01_MasterData_Store_Flow.py b/M01_MasterData/M01_MasterData_Store_Flow.py
new file mode 100644
index 000000000..eb2d329f7
--- /dev/null
+++ b/M01_MasterData/M01_MasterData_Store_Flow.py
@@ -0,0 +1,269 @@
+"""M01 로직 「흐름」 칸(PLAN 36-4 · 정함 1 · 2 · 4 · 10 · 11 · 12).
+
+정함 = `docs/raw/M01_쉬운단가/흐름도_적용_정함.md`.
+
+· 흐름 = DataFlow Model `CfLogic` 꼴 그대로 · 로직 줄 칸 「흐름」 · 있으면 흐름이 정본
+· 쓰는 때 = `/save` 줄에 실어 온 것뿐(자동 변환 결과는 안 씀) — 꼴 검사(상자 · 선 · 돌고 도는 선) →
+  서버 셈(`M02_DF_Compute.run`)으로 다시 셈 → 받는 칸에 값만 되돌려 넣음 · 빈 받는 자리는 경고
+· 새 줄(키 없음) + 흐름 = 자체 파일(`로직_자체.json`)에 더함 → 키 = 대장 `GX` 다음 · 구분 자체
+· 계산 = 흐름이 있으면 흐름 셈 · 없으면 옛 셈(`Store.calc`) · 입력 이름 = 「설계 때 정할 것」
+· 다른 로직 입력 = 마스터 키도 — 흐름 로직은 흐름 셈 · 옛 로직은 옛 셈(노무비 · 재료비 · 경비 · 계)
+· 흐름 받기 = 줄의 흐름 그대로 · 없으면 sub7 변환(`M02_DF_Convert.convert`) · 아직 없으면 빈 흐름
+권한 = `/api/m01` 전체가 시스템 관리자(`main.py`) — 공용 로직 흐름도 관리자가 고침.
+"""
+
+from __future__ import annotations
+
+import importlib
+from decimal import Decimal, InvalidOperation
+from typing import Any
+
+from M01_MasterData import M01_MasterData_Store as store
+from M01_MasterData import M01_MasterData_Store_Make as make
+from M02_MasterTemplete.DataFlow import M02_DF_Compute as dc
+
+FLOW = "흐름"
+KINDS = ("input", "function", "output")
+CONVERT = "M02_MasterTemplete.DataFlow.M02_DF_Convert"
+NOT_READY = "변환 준비 중"
+
+
+# ── 검사(Model `link` · `ruleWhy` 와 같은 뜻) ──────────────────────────────
+def _outs(box: dict) -> set:
+    """내보내는 알약 — Model `portsOut`."""
+    if box.get("kind") == "function":
+        return {((box.get("func") or {}).get("output") or {}).get("name")}
+    inp = box.get("input") or {}
+    if box.get("kind") != "input":
+        return set()
+    if inp.get("mode") == "logic":
+        return {p.get("name") for p in (inp.get("logic") or {}).get("outputs") or []}
+    out = {dc._port(e) for e in inp.get("elements") or []} if inp.get("mode") == "group" else set()
+    if inp.get("mode") == "group" and inp.get("table"):
+        out.add(dc.TABLE_PORT)
+    return out | {v.get("name") for v in inp.get("variables") or []}
+
+
+def _ins(box: dict) -> set:
+    """받는 알약 — Model `portsIn`."""
+    if box.get("kind") == "function":
+        return {p.get("port") for p in (box.get("func") or {}).get("inputs") or []}
+    if box.get("kind") == "output":
+        return {dc.OUTPUT_PORT}
+    inp = box.get("input") or {}
+    return {p.get("name") for p in (inp.get("logic") or {}).get("designs") or []}
+
+
+def check(flow: Any) -> list[str]:
+    """흐름 꼴 검사 — 틀리면 422 · 돌려받는 것 = 경고(빈 받는 자리)."""
+    if not isinstance(flow, dict) or not isinstance(flow.get("boxes"), list):
+        raise store.StoreError(422, {"errors": ["흐름 꼴이 아님 — 상자(boxes) 목록이 없음"]})
+    if not isinstance(flow.get("links"), list):
+        raise store.StoreError(422, {"errors": ["흐름 꼴이 아님 — 선(links) 목록이 없음"]})
+    errors, boxes = [], {}
+    for b in flow["boxes"]:
+        if not isinstance(b, dict) or not b.get("id"):
+            errors.append("번호(id) 없는 상자가 있음")
+            continue
+        name = b.get("name") or b["id"]
+        if b["id"] in boxes:
+            errors.append(f"상자 번호가 겹침 「{b['id']}」")
+        boxes[b["id"]] = b
+        if b.get("kind") not in KINDS:
+            errors.append(f"「{name}」 모르는 상자 종류 「{b.get('kind')}」")
+        elif b["kind"] == "function" and not ((b.get("func") or {}).get("output") or {}).get(
+            "name"
+        ):
+            errors.append(f"「{name}」 함수 상자에 결과 알약이 없음")
+    taken = set()
+    for ln in flow["links"]:
+        src, to = (ln or {}).get("from") or {}, (ln or {}).get("to") or {}
+        a, b = boxes.get(src.get("box")), boxes.get(to.get("box"))
+        if (
+            a is None
+            or b is None
+            or src.get("name") not in _outs(a)
+            or to.get("name") not in _ins(b)
+        ):
+            errors.append(f"선 「{(ln or {}).get('id')}」 이 없는 알약을 이음")
+            continue
+        if (to["box"], to["name"]) in taken:
+            errors.append(f"「{b.get('name')} · {to['name']}」 에 선이 둘 이상")
+        taken.add((to["box"], to["name"]))
+        for p in dc._sources(ln.get("rule")):
+            if p.get("name") not in _outs(boxes.get(p.get("box")) or {}):
+                errors.append(f"선 「{ln.get('id')}」 규칙의 조건 알약이 없음")
+    if not errors:
+        errors += [
+            f"「{b.get('name')}」 상자가 서로를 기다림(돌고 도는 선)" for b in dc._waves(flow)[1]
+        ]
+    if errors:
+        raise store.StoreError(422, {"errors": errors})
+    return [
+        f"「{b.get('name')} · {port}」 받는 자리에 들어오는 선이 없음"
+        for b in boxes.values()
+        if b.get("kind") != "input"
+        for port in sorted(_ins(b) - {n for bx, n in taken if bx == b["id"]}, key=str)
+    ]
+
+
+# ── 다른 로직 · 계산 ───────────────────────────────────────────────────
+def _old(key: str, designs: dict) -> dict:
+    """옛 로직 값 — 옛 셈 · 내보내는 알약 = 노무비 · 재료비 · 경비 · 계(돈 아닌 로직은 결과)."""
+    got = store.calc(key, {k: v for k, v in designs.items() if v is not None})
+    if not got.get("ok"):
+        return {"outputs": {}, "errors": [got.get("reason") or "옛 셈 오류"]}
+    if "result" in got:
+        return {"outputs": {"결과": got["result"]}, "errors": []}
+    return {"outputs": dict(got["sums"]), "errors": []}
+
+
+def load(key: str) -> dict:
+    """다른 로직 입력이 부르는 마스터 로직 — 흐름이면 흐름 · 옛 로직이면 옛 셈 함수(`calc`)."""
+    row = store.logic(key)["logic"]
+    if isinstance(row.get(FLOW), dict):
+        return {**row[FLOW], "key": key}
+    return {"key": key, "calc": lambda designs: _old(key, designs)}
+
+
+def old_designs(key: str) -> list[dict]:
+    """옛 로직의 받는 알약 = 로직 입력 — Model `CfDesign` 꼴."""
+    out = []
+    for one in store.logic(key)["logic"].get("입력") or []:
+        choices = one.get("고르기")
+        variable = {"name": one.get("이름"), "type": "choice" if choices else "number",
+                    "unit": one.get("단위") or "-", "example": None}  # fmt: skip
+        if choices:
+            variable["choices"] = choices
+        out.append({"box": "", "port": one.get("이름"), "kind": "변수",
+                    "unit": one.get("단위") or "-", "variable": variable})  # fmt: skip
+    return out
+
+
+def _value(v: Any) -> Any:
+    """화면이 보낸 값 — 수 글은 수로(「3」 → 3) · 그 밖은 그대로."""
+    if isinstance(v, str) and v.strip():
+        try:
+            return Decimal(v.strip())
+        except InvalidOperation:
+            return v
+    return store._dec(v)
+
+
+def run(flow: dict, key: str, inputs: dict) -> dict:
+    """흐름 셈 — 입력 = 「설계 때 정할 것」 이름 → 값."""
+    given = {k: _value(v) for k, v in (inputs or {}).items()}
+    flow = {**flow, "key": key}
+    return dc.run(flow, dc._design_values(flow, given), load, flow.get("userElements") or [], [key])
+
+
+def calc(key: str, inputs: dict, row: dict | None = None) -> dict | None:
+    """계산 갈래 — 줄에 흐름이 없으면 None(옛 셈 그대로) · 있으면 흐름 셈을 `/calc` 꼴로."""
+    if row is not None:
+        flow, key = row.get(FLOW), str(row.get("키") or key)
+    else:
+        try:
+            flow = store.logic(key)["logic"].get(FLOW)
+        except store.StoreError:
+            return None
+    if not isinstance(flow, dict):
+        return None
+    got = run(flow, key, inputs)
+    names = {b["id"]: b for b in flow.get("boxes") or []}
+    outputs = [
+        {"box": i, "name": names[i].get("name"), "cost": (names[i].get("output") or {}).get("cost"),
+         "unit": (names[i].get("output") or {}).get("unit") or names[i].get("unit"), "value": v}
+        for i, v in got["outputs"].items() if i in names
+    ]  # fmt: skip
+    cost = got["cost"]
+    out = {"ok": not got["errors"], "flow": True, "lines": [], "middle": {},
+           "sums": {k: cost[k] for k in (*dc.COSTS, "계")}, "values": cost["값들"],
+           "outputs": outputs, "errors": got["errors"], "breaks": got["breaks"]}  # fmt: skip
+    if got["errors"]:
+        out["reason"] = " · ".join(got["errors"])
+    return out
+
+
+# ── 흐름 받기 ──────────────────────────────────────────────────────────
+def _row(file: str, key: str) -> dict:
+    if not file:
+        return store.logic(key)["logic"]
+    data = store.read(file)[0]
+    hit = next((r for r in data.get("줄") or [] if str(r.get("키")) == key), None)
+    if hit is None:
+        raise store.StoreError(404, f"{file} · 없는 키 「{key}」")
+    return hit
+
+
+def get_flow(file: str, key: str) -> dict:
+    """{flow, converted, notes} — 흐름이 있으면 그대로 · 없으면 변환(파일은 안 바뀜)."""
+    row = _row(file, key)
+    if isinstance(row.get(FLOW), dict):
+        return {"flow": {**row[FLOW], "key": key}, "converted": False, "notes": []}
+    try:
+        convert = importlib.import_module(CONVERT).convert
+    except ModuleNotFoundError as e:
+        if e.name != CONVERT:
+            raise
+        empty = {"key": key, "name": row.get("이름") or "", "resultUnit": row.get("결과단위") or "",
+                 "boxes": [], "links": [], "userElements": []}  # fmt: skip
+        return {"flow": empty, "converted": True, "notes": [NOT_READY]}
+    got = convert(row, {"key": key, "file": file, "master": store.loaded()[1]})
+    return {"flow": {**got["flow"], "key": key}, "converted": True, "notes": got.get("notes") or []}
+
+
+# ── 저장 ──────────────────────────────────────────────────────────────
+def _redo(row: dict, key: str) -> list[str]:
+    """흐름 검사 → 서버 셈으로 다시 셈 → 받는 칸 값만 되돌려 넣음 · 돌려받는 것 = 경고."""
+    warns = check(row[FLOW])
+    got = run(row[FLOW], key, {})
+    filled = got["filled"]
+    filled.pop("key", None)  # 키는 줄의 「키」 하나 — 흐름 안에 두지 않음
+    row[FLOW] = filled
+    return warns + got["errors"]
+
+
+def _bare(row: dict) -> dict:
+    """새 흐름 로직 — 옛 식 칸은 빈 것으로(파일 틀 검사) · 출처 없으면 「자체」."""
+    old = {"입력": [], "중간": [], "호표": [], "끝수": None}
+    return {**old, **row, "출처": row.get("출처") or "자체"}
+
+
+def save(batch: list[dict]) -> dict:
+    """`/save` — 흐름 줄은 검사 · 다시 셈 · 새 줄은 자체 GX · 그 밖은 `Store.save` 그대로."""
+    warns, fresh = [], False
+    for part in batch:
+        for ch in part.get("changes") or []:
+            row = ch.get("row")
+            if not isinstance(row, dict) or FLOW not in row:
+                continue
+            new = ch.get("op") == "add" or (ch.get("op") == "edit" and not ch.get("key"))
+            if new:
+                if part.get("file") != make.OWN:
+                    raise store.StoreError(400, f"새 흐름 로직은 「{make.OWN}」 에만 더함")
+                row = make._clean(_bare(row), str(row.get("소유") or make.OWNERS[0]))
+                ch.update(op="add", key=None)
+            ch["row"] = row
+            name = row.get("이름") or ch.get("key") or "새 로직"
+            warns += [f"「{name}」 {w}" for w in _redo(row, str(ch.get("key") or ""))]
+        if part.get("file") == make.OWN and not make._own_path().is_file():
+            make._make_file()
+            fresh = True
+            part["version"] = part.get("version") or store.read(make.OWN)[1]
+    before = {p["file"]: _keys(p["file"]) for p in batch}
+    try:
+        files = store.save(batch)
+    except store.StoreError:
+        if fresh:
+            make._own_path().unlink(missing_ok=True)
+        raise
+    added = [{"file": f, "key": k} for f, old in before.items() for k in _keys(f) if k not in old]
+    return {"files": files, "added": added, "warnings": warns}
+
+
+def _keys(file: str) -> list[str]:
+    try:
+        data = store.read(file)[0]
+    except store.StoreError:
+        return []
+    return [str(r.get("키")) for r in data.get(store.items_key(data)) or []]
diff --git a/M02_MasterTemplete/DataFlow/M02_DF_Compute.py b/M02_MasterTemplete/DataFlow/M02_DF_Compute.py
index 331a2a151..e3d8cf96b 100644
--- a/M02_MasterTemplete/DataFlow/M02_DF_Compute.py
+++ b/M02_MasterTemplete/DataFlow/M02_DF_Compute.py
@@ -23,8 +23,10 @@ from decimal import ROUND_DOWN, ROUND_HALF_UP, ROUND_UP, Decimal
 from typing import Any, Callable
 
 from common_util import common_util_spreadsheet as spreadsheet
+from M01_MasterData import (
+    M01_MasterData_Router as m01,
+)  # _num — M01 Router 가 이 파일을 부름(서로 부름)
 from M01_MasterData import M01_MasterData_Store as store
-from M01_MasterData.M01_MasterData_Router import _num
 from M02_MasterTemplete.DataFlow import M02_DF_Values as dv
 
 _CELL = re.compile(r"^([A-Z]+)(\d+)$")
@@ -188,6 +190,12 @@ def _logic_ports(lg: dict, box: dict, given: dict, ports: dict, errors: list, ct
         if link.get("to", {}).get("box") == box["id"]:
             src = link.get("from") or {}
             designs[link["to"].get("name")] = ports.get(src.get("box"), {}).get(src.get("name"))
+    if callable(
+        other.get("calc")
+    ):  # 옛 마스터 로직(흐름 없음) — 옛 셈 · 노무비 · 재료비 · 경비 · 계
+        result = other["calc"](designs)
+        errors += [f"「{box.get('name')}」 {x}" for x in result["errors"]]
+        return result["outputs"]
     stack = [*ctx["stack"], key]
     result = run(other, _design_values(other, designs), ctx["load"], ctx["local"], stack)
     errors += [f"「{box.get('name')}」 {x}" for x in result["errors"]]
@@ -559,7 +567,9 @@ def run(lg: dict, values: dict, load: Loader, local: list[dict], stack: list | N
                 outputs[b["id"]] = arrive(b).get(OUTPUT_PORT)
         if funcs:  # 이 물결의 함수 시트를 한 번에(시트마다 통합문서 하나 — Eval 과 같음)
             books = [
-                _num({"종류": "통합문서", "판": 1, "서식": [{}] * 64, "시트": [sheets[f["id"]]]})
+                m01._num(
+                    {"종류": "통합문서", "판": 1, "서식": [{}] * 64, "시트": [sheets[f["id"]]]}
+                )
                 for f in funcs
             ]
             try:
diff --git a/M02_MasterTemplete/DataFlow/M02_DF_Router.py b/M02_MasterTemplete/DataFlow/M02_DF_Router.py
index c7375090c..3892588d9 100644
--- a/M02_MasterTemplete/DataFlow/M02_DF_Router.py
+++ b/M02_MasterTemplete/DataFlow/M02_DF_Router.py
@@ -36,6 +36,7 @@ from fastapi import APIRouter, HTTPException
 from pydantic import BaseModel
 
 from M01_MasterData import M01_MasterData_Store as store
+from M01_MasterData import M01_MasterData_Store_Flow as sflow
 from M01_MasterData.M01_MasterData_Router import _num
 from M02_MasterTemplete.DataFlow import M02_DF_Compute as dc
 from M02_MasterTemplete.DataFlow import M02_DF_Values as dv
@@ -184,7 +185,10 @@ def user_edit(op: str, element: dict | None, uid: str | None) -> dict:
 
 # ── 저장 · 계산(`M02_DF_Compute`) ─────────────────────────────────────
 def _load(key: str) -> dict:
-    """다른 로직 입력이 부르는 로직 — 내 것(`_data`) · 견본(`_sample`)."""
+    """다른 로직 입력이 부르는 로직 — 내 것(`_data`) · 견본(`_sample`) · 마스터 키(GX · GF …)는
+    M01 계산 길(흐름이면 흐름 · 옛 로직이면 옛 셈 · 정함 11)."""
+    if not _KEY.match(key or "") and _sample(key) is None:
+        return sflow.load(key)
     logic, _ = _read(key)
     return {**logic, "key": key}
 
@@ -216,6 +220,9 @@ def save(logic: dict) -> dict:
 def logic_value(key: str, designs: dict) -> dict:
     """다른 로직 값 — 저장 로직 · 견본을 받은 설계 값(없으면 예시값)으로 셈 · 출력 이름 → 값."""
     other = _load(key)
+    if callable(other.get("calc")):  # 옛 마스터 로직 — 노무비 · 재료비 · 경비 · 계
+        got = other["calc"](designs)
+        return {"key": key, "outputs": got["outputs"], "cost": {}, "errors": got["errors"]}
     got = dc.run(other, dc._design_values(other, designs), _load, _local(other), [key])
     names = {b["id"]: b.get("name") for b in other.get("boxes") or []}
     outputs = {names[i]: v for i, v in got["outputs"].items() if i in names}
@@ -224,7 +231,10 @@ def logic_value(key: str, designs: dict) -> dict:
 
 def design_inputs(key: str) -> dict:
     """설계 때 정할 것 — 변수 · 재료 자리 · 다른 로직 받는 알약(선이 없을 때) · CfDesign 꼴."""
-    return {"key": key, "designs": dc.design_inputs(_load(key))}
+    other = _load(key)
+    if callable(other.get("calc")):
+        return {"key": key, "designs": sflow.old_designs(key)}
+    return {"key": key, "designs": dc.design_inputs(other)}
 
 
 # ── 길 ────────────────────────────────────────────────────────────────
diff --git a/resources/tester/test_m01_logic_flow_save.py b/resources/tester/test_m01_logic_flow_save.py
new file mode 100644
index 000000000..312664317
--- /dev/null
+++ b/resources/tester/test_m01_logic_flow_save.py
@@ -0,0 +1,240 @@
+# ruff: noqa: E501
+"""흐름도 적용(PLAN 36-4 서버 · 정함 1 · 2 · 4 · 10 · 11 · 12) — 로직 줄 「흐름」 칸.
+
+못박는 것(마스터 사본 폴더에서만 · 정본은 안 바뀜)
+  - `/save` 줄에 실은 흐름 = 검사 → 서버 다시 셈(받는 칸에 값) → 파일에 씀 · 다시 읽으면 그대로
+  - 흐름 꼴이 틀리면(없는 알약 · 돌고 도는 선) 422 · 빈 받는 자리는 경고
+  - `/calc` 갈래 — 흐름 있으면 흐름 셈(입력 = 설계 때 정할 것 · 노무비 · 재료비 · 경비 · 계) · 없으면 옛 셈
+  - 새 줄(키 없음) + 흐름 → 자체 파일 GX 다음 키 · 구분 자체 · 본떠 만들기는 흐름도 함께
+  - `GET /logic/flow` — 흐름 있으면 그대로 · 없으면 변환(준비 전이면 빈 흐름 + 「변환 준비 중」)
+  - DataFlow 다른 로직 값 · 설계 입력이 마스터 키도 받음(흐름 · 옛 로직) · 서로 부르면 막음
+  - 시스템 관리자가 아니면 403
+"""
+
+from __future__ import annotations
+
+import copy
+import hashlib
+import importlib.util
+import shutil
+from decimal import Decimal
+from pathlib import Path
+
+import pytest
+from fastapi import Depends, FastAPI
+from fastapi.testclient import TestClient
+
+from common_util.common_util_auth import require_system_admin, verify_session
+from M01_MasterData import M01_MasterData_Router as m01_router
+from M01_MasterData import M01_MasterData_Store as store
+from M01_MasterData import M01_MasterData_Store_Flow as sflow
+from M02_MasterTemplete.DataFlow import M02_DF_Router as df
+
+REAL = store.FOLDER
+KEY = "GF000219"  # 13-4-1 메쌓기 — 흐름을 얹어 볼 정본 로직
+OLD = "GF000160"  # 12-4 합판거푸집 — 흐름 없는 옛 로직
+OWN = "로직_자체.json"
+
+
+def _flow(name: str = "넓이 품") -> dict:
+    """길이 × 폭 × 1000 → 노무비 — 입력 상자(변수 둘) · 함수 상자 · 출력 상자."""
+    sheet = {"id": "s-fn", "이름": "넓이", "칸": {"A2": {"값": "길이"}, "A3": {"값": "폭"},
+             "A4": {"값": "금액"}, "B4": {"식": "B2*B3*1000"}}}  # fmt: skip
+    return {
+        "key": None, "name": name, "resultUnit": "원/㎡", "userElements": [],
+        "boxes": [
+            {"id": "in", "kind": "input", "name": "치수", "color": "", "unit": "-", "x": 0, "y": 0,
+             "input": {"mode": "variable", "elements": [], "variables": [
+                 {"name": "길이", "type": "number", "unit": "m", "example": 2},
+                 {"name": "폭", "type": "number", "unit": "m", "example": 3}]}},
+            {"id": "fn", "kind": "function", "name": "넓이 금액", "color": "", "unit": "원", "x": 0, "y": 0,
+             "func": {"sheet": sheet, "inputs": [{"port": "길이", "cell": "B2"}, {"port": "폭", "cell": "B3"}],
+                      "variables": [], "output": {"cell": "B4", "name": "금액", "unit": "원"}}},
+            {"id": "out", "kind": "output", "name": "노무비", "color": "", "unit": "원/㎡", "x": 0, "y": 0,
+             "output": {"cost": "노무비", "unit": "원/㎡"}},
+        ],
+        "links": [
+            {"id": "l1", "from": {"box": "in", "name": "길이"}, "to": {"box": "fn", "name": "길이"}},
+            {"id": "l2", "from": {"box": "in", "name": "폭"}, "to": {"box": "fn", "name": "폭"}},
+            {"id": "l3", "from": {"box": "fn", "name": "금액"}, "to": {"box": "out", "name": "값"}},
+        ],
+    }  # fmt: skip
+
+
+def _hashes(folder: Path) -> dict[str, str]:
+    return {p.name: hashlib.sha1(p.read_bytes()).hexdigest() for p in folder.glob("*.json")}
+
+
+@pytest.fixture
+def folder(tmp_path: Path, monkeypatch) -> Path:
+    master = tmp_path / "master"
+    master.mkdir()
+    for path in REAL.glob("*.json"):
+        shutil.copy(path, master / path.name)
+    monkeypatch.setattr(store, "FOLDER", master)
+    monkeypatch.setattr(df, "DATA", tmp_path / "_data")
+    return master
+
+
+@pytest.fixture
+def client(folder: Path) -> TestClient:
+    app = FastAPI()
+    app.include_router(m01_router.router)
+    app.include_router(df.router)
+    return TestClient(app)
+
+
+def _get(client: TestClient, url: str, want: int = 200, **params) -> dict:
+    res = client.get(url, params=params)
+    assert res.status_code == want, res.text
+    return res.json()
+
+
+def _post(client: TestClient, url: str, body: dict, want: int = 200) -> dict:
+    res = client.post(url, json=body)
+    assert res.status_code == want, res.text
+    return res.json()
+
+
+def _save_flow(client: TestClient, key: str, flow: dict, want: int = 200) -> dict:
+    got = _get(client, "/api/m01/logic", key=key)
+    row = {**got["logic"], "흐름": flow}
+    part = {"file": got["file"], "version": got["version"],
+            "changes": [{"op": "edit", "key": key, "row": row}]}  # fmt: skip
+    return _post(client, "/api/m01/save", {"files": [part]}, want)
+
+
+def test_흐름_저장_다시_셈_다시_읽기(client: TestClient, folder: Path) -> None:
+    before = _hashes(REAL)
+    done = _save_flow(client, KEY, _flow())
+    assert done["warnings"] == [] and done["added"] == []
+    saved = _get(client, "/api/m01/logic", key=KEY)["logic"]["흐름"]
+    cells = saved["boxes"][1]["func"]["sheet"]["칸"]
+    assert (
+        Decimal(str(cells["B2"]["값"])) == 2 and Decimal(str(cells["B3"]["값"])) == 3
+    )  # 서버가 넣은 값
+    assert "key" not in saved
+    got = _get(client, "/api/m01/logic/flow", key=KEY)
+    assert got["converted"] is False and got["notes"] == [] and got["flow"]["key"] == KEY
+    assert [b["id"] for b in got["flow"]["boxes"]] == ["in", "fn", "out"]
+    assert _hashes(REAL) == before  # 사본 밖(정본)은 안 바뀜
+
+
+def test_흐름_꼴_검사_422_와_빈_자리_경고(client: TestClient) -> None:
+    bad = _flow()
+    bad["links"][0]["from"]["name"] = "없는알약"
+    assert "없는 알약" in str(_save_flow(client, KEY, bad, 422))
+    loop = _flow()
+    loop["boxes"].append({**copy.deepcopy(loop["boxes"][1]), "id": "fn2", "name": "되돌이"})
+    loop["links"] += [
+        {"id": "l4", "from": {"box": "fn", "name": "금액"}, "to": {"box": "fn2", "name": "길이"}},
+        {"id": "l5", "from": {"box": "fn2", "name": "금액"}, "to": {"box": "fn", "name": "폭"}},
+    ]
+    loop["links"] = [x for x in loop["links"] if x["id"] != "l2"]
+    assert "돌고 도는" in str(_save_flow(client, KEY, loop, 422))
+    empty = _flow()
+    empty["links"] = [x for x in empty["links"] if x["id"] != "l2"]
+    warns = _save_flow(client, KEY, empty)["warnings"]
+    assert any("넓이 금액 · 폭" in w for w in warns), warns
+
+
+def test_계산_갈래_흐름이면_흐름_셈_아니면_옛_셈(client: TestClient) -> None:
+    _save_flow(client, KEY, _flow())
+    got = _post(client, "/api/m01/calc", {"key": KEY, "inputs": {"길이": 4, "폭": "5"}})
+    assert got["flow"] is True and got["ok"] is True
+    assert {k: Decimal(str(v)) for k, v in got["sums"].items()} == {
+        "노무비": 20000, "재료비": 0, "경비": 0, "계": 20000}  # fmt: skip
+    assert (
+        got["outputs"][0]["name"] == "노무비" and Decimal(str(got["outputs"][0]["value"])) == 20000
+    )
+    plain = _post(client, "/api/m01/calc", {"key": KEY, "inputs": {}})  # 예시값 2 × 3
+    assert Decimal(str(plain["sums"]["계"])) == 6000
+    row = {**_get(client, "/api/m01/logic", key=KEY)["logic"], "흐름": _flow()}  # 저장 전 줄
+    row["흐름"]["boxes"][1]["func"]["sheet"]["칸"]["B4"] = {"식": "B2*B3*10"}
+    draft = _post(client, "/api/m01/calc", {"key": KEY, "inputs": {}, "row": row})
+    assert Decimal(str(draft["sums"]["계"])) == 60
+    old = _post(client, "/api/m01/calc", {"key": OLD, "inputs": {}})
+    assert "flow" not in old  # 흐름 없는 로직은 옛 셈 그대로
+
+
+def test_신규_흐름_로직은_자체_GX_복사는_흐름도(client: TestClient, folder: Path) -> None:
+    version = store.read(OWN)[1] if (folder / OWN).is_file() else ""
+    row = {"키": "", "이름": "시험 흐름 로직", "결과단위": "원/㎡", "출처": "", "구분": "산림품셈",
+           "흐름": _flow("시험 흐름 로직")}  # fmt: skip
+    part = {"file": OWN, "version": version, "changes": [{"op": "add", "row": row}]}
+    done = _post(client, "/api/m01/save", {"files": [part]})
+    assert len(done["added"]) == 1 and done["added"][0]["file"] == OWN
+    key = done["added"][0]["key"]
+    assert key.startswith("GX")
+    saved = _get(client, "/api/m01/logic", key=key)["logic"]
+    assert saved["구분"] == "자체" and saved["흐름"]["name"] == "시험 흐름 로직"
+    assert (
+        Decimal(str(_post(client, "/api/m01/calc", {"key": key, "inputs": {}})["sums"]["계"]))
+        == 6000
+    )
+    made = _post(client, "/api/m01/logic/copy", {"key": key, "이름": "복사한 흐름"})
+    assert made["key"].startswith("GX") and made["key"] != key
+    copied = _get(client, "/api/m01/logic/flow", key=made["key"])
+    assert copied["converted"] is False and len(copied["flow"]["boxes"]) == 3
+    bad = {"file": OWN, "version": store.read(OWN)[1], "changes": [{"op": "add", "row": row}]}
+    bad["changes"][0]["row"] = {**row, "흐름": {"boxes": "아님"}}
+    _post(client, "/api/m01/save", {"files": [bad]}, 422)
+
+
+def test_흐름_없는_로직_받기는_변환(client: TestClient) -> None:
+    got = _get(client, "/api/m01/logic/flow", key=OLD)
+    assert got["converted"] is True and got["flow"]["key"] == OLD
+    if importlib.util.find_spec(sflow.CONVERT) is None:  # sub7 변환이 오기 전
+        assert got["notes"] == [sflow.NOT_READY] and got["flow"]["boxes"] == []
+    _get(client, "/api/m01/logic/flow", 404, key="GX999999")
+
+
+def test_다른_로직_값_마스터_키_흐름_옛_순환(client: TestClient) -> None:
+    _save_flow(client, KEY, _flow())
+    got = _post(client, "/api/m02/df/logic-value", {"key": KEY, "designs": {"길이": 10}})
+    assert Decimal(str(got["outputs"]["노무비"])) == 30000 and got["errors"] == []
+    designs = _get(client, "/api/m02/df/design-inputs", key=KEY)["designs"]
+    assert [d["port"] for d in designs] == ["길이", "폭"]
+    given = {k: str(v) for k, v in store.cm.시험입력(store.logic(OLD)["logic"]).items()}
+    old = _post(client, "/api/m02/df/logic-value", {"key": OLD, "designs": given})
+    want = _post(client, "/api/m01/calc", {"key": OLD, "inputs": given})
+    assert old["outputs"] == want["sums"] and set(old["outputs"]) == {
+        "노무비",
+        "재료비",
+        "경비",
+        "계",
+    }
+    names = [d["port"] for d in _get(client, "/api/m02/df/design-inputs", key=OLD)["designs"]]
+    assert names == [x["이름"] for x in store.logic(OLD)["logic"].get("입력") or []]
+    # 흐름 안 다른 로직 입력이 옛 로직(OLD) 계 를 받아 노무비로 · 자기 자신을 부르면 막힘
+    flow = _flow()
+    pills = [{"name": k, "unit": "-"} for k in given]
+    ref = {"key": OLD, "outputs": [{"name": "계", "unit": "원"}], "designs": pills}
+    flow["boxes"].append({"id": "lg", "kind": "input", "name": "거푸집", "color": "", "unit": "-",
+                          "x": 0, "y": 0, "input": {"mode": "logic", "elements": [], "variables": [],
+                                                    "logic": ref}})  # fmt: skip
+    flow["boxes"].append({**copy.deepcopy(flow["boxes"][2]), "id": "out2", "name": "경비"})
+    flow["boxes"][-1]["output"]["cost"] = "경비"
+    flow["links"].append(
+        {"id": "l9", "from": {"box": "lg", "name": "계"}, "to": {"box": "out2", "name": "값"}}
+    )
+    _save_flow(client, KEY, flow)
+    mixed = _post(client, "/api/m01/calc", {"key": KEY, "inputs": given})
+    assert Decimal(str(mixed["sums"]["경비"])) == Decimal(str(want["sums"]["계"]))
+    ref["key"] = KEY
+    self_call = _save_flow(client, KEY, flow)["warnings"]
+    assert any("서로를 부름" in w for w in self_call), self_call
+
+
+def test_시스템_관리자가_아니면_403(folder: Path) -> None:
+    app = FastAPI()
+    app.include_router(
+        m01_router.router, dependencies=[Depends(verify_session), Depends(require_system_admin)]
+    )
+    app.dependency_overrides[verify_session] = lambda: {"role": "USER", "company_id": 1}
+    client = TestClient(app)
+    before = _hashes(folder)
+    assert client.get("/api/m01/logic/flow", params={"key": KEY}).status_code == 403
+    assert client.post("/api/m01/save", json={"files": []}).status_code == 403
+    assert client.post("/api/m01/calc", json={"key": KEY, "inputs": {}}).status_code == 403
+    assert _hashes(folder) == before