diff --git a/5_django_backend/apps/chat/stream.py b/5_django_backend/apps/chat/stream.py
index 80fb018..d4c8139 100644
--- a/5_django_backend/apps/chat/stream.py
+++ b/5_django_backend/apps/chat/stream.py
@@ -192,6 +192,21 @@ class TurnState:
         return out
 
 
+def _tool_spans(tid: str, root: dict, tool_parts: list[dict]) -> list[dict]:
+    """OpenCode 도구 파트 → Langfuse 자식 span. 출력은 앞 4KB 만(원문은 OpenCode 에 있음)."""
+    out = []
+    for p in tool_parts:
+        st = p.get("state") or {}
+        t = st.get("time") or {}
+        out.append(langfuse.tool_span(
+            tid, p.get("tool") or "tool", parent=root, input=st.get("input"), title=st.get("title") or "",
+            output=(st.get("output") or "")[:4000] or None,
+            start=langfuse.ms_iso(t.get("start")), end=langfuse.ms_iso(t.get("end")),
+            error=st.get("error") if st.get("status") == "error" else None,
+        ))
+    return out
+
+
 def _real_title(raw) -> str | None:
     """OpenCode 기본 제목("New session - 2026-…")은 제목이 아님 → None."""
     t = (raw or "").strip()
@@ -212,12 +227,15 @@ async def _finalize(session: ChatSession, state: TurnState, started: float, *, f
     content = state.accumulated()
     usage: dict | None = None
     title = state.title
+    tool_parts: list[dict] = []
     try:
         msgs = await opencode_service.list_messages_a(session.id) or []
         assistant = [m for m in msgs if (m.get("info") or {}).get("role") == "assistant"]
         if assistant:
             info = assistant[-1]["info"]
             parts = assistant[-1].get("parts") or []
+            # 이 턴의 assistant 메시지가 여러 개(도구 왕복마다 하나)라 도구 파트는 전부 모음
+            tool_parts = [p for m in assistant for p in (m.get("parts") or []) if p.get("type") == "tool"]
             full = "".join(p.get("text", "") for p in parts if p.get("type") == "text" and not p.get("synthetic"))
             if full:
                 content = full
@@ -251,25 +269,18 @@ async def _finalize(session: ChatSession, state: TurnState, started: float, *, f
         session.title_llm = title[:200]
     await session.asave(update_fields=["is_generating", "title_llm", "updated_at"])
 
-    # 관측: 사용자 단위 trace 하나 + 답변 generation 하나. 실패해도 여기까진 이미 저장됨.
+    # 관측: 목록 한 줄 = 이 채팅(질문·답·토큰). 트리 = 답 만들며 부른 도구들(SAP 조회·위키 read…) 순서대로.
     if langfuse.enabled():
         tid = f"{session.id}-{int(started * 1000)}"
         user_email = await sync_to_async(lambda: session.user.email)()
-        meta = {"failed": failed} if failed else {}
         t0 = datetime.fromtimestamp(started, timezone.utc).isoformat()
-        root = langfuse.trace(tid, "chat", userId=user_email, sessionId=session.id, input=state.user_text,
-                              output=content, metadata=meta, tags=["codeassist"], start=t0, end=langfuse.now_iso())
-        langfuse.send_later([
-            root,
-            langfuse.generation(
-                tid, "opencode-turn", parent=root,
-                startTime=t0, endTime=langfuse.now_iso(),
-                input=state.user_text, output=content,
-                usage=langfuse.usage_of(usage["input"], usage["output"]) if usage else None,
-                level="ERROR" if failed else "DEFAULT", statusMessage=failed or "",
-                metadata={"elapsed_ms": usage["elapsed_ms"]} if usage else {},
-            ),
-        ])
+        root = langfuse.trace(
+            tid, "chat", userId=user_email, sessionId=session.id, input=state.user_text, output=content,
+            tags=["codeassist"], start=t0, end=langfuse.now_iso(),
+            usage=langfuse.usage_of(usage["input"], usage["output"]) if usage else None,
+            metadata={"elapsed_ms": usage["elapsed_ms"]} if usage else {}, error=failed,
+        )
+        langfuse.send_later([root, *_tool_spans(tid, root, tool_parts)])
     return usage, title
 
 
diff --git a/5_django_backend/apps/gateway/langfuse.py b/5_django_backend/apps/gateway/langfuse.py
index 1cb6291..03531b8 100644
--- a/5_django_backend/apps/gateway/langfuse.py
+++ b/5_django_backend/apps/gateway/langfuse.py
@@ -78,11 +78,17 @@ def _span(trace_id: str, name: str, attrs: dict, *, start: str | None, end: str
 
 
 def trace(trace_id: str, name: str, *, userId: str = "", sessionId: str = "", input=None, output=None,
-          metadata: dict | None = None, tags: list[str] | None = None, start: str | None = None, end: str | None = None) -> dict:
-    """루트 span. trace 속성(이름·사용자·세션·태그)은 여기 실림."""
+          metadata: dict | None = None, tags: list[str] | None = None, start: str | None = None, end: str | None = None,
+          usage: dict | None = None, model: str = "", error: str | None = None) -> dict:
+    """루트 span. trace 속성(이름·사용자·세션·태그)은 여기 실림.
+    usage 를 주면 루트 자체가 generation — 목록 한 줄 = 질문/답/토큰, 밑에 도구 호출만 트리로."""
     attrs = {
         "langfuse.trace.name": name,
-        "langfuse.observation.type": "span",
+        "langfuse.observation.type": "generation" if usage else "span",
+        "langfuse.observation.model.name": model,
+        "langfuse.observation.usage_details": usage,
+        "langfuse.observation.level": "ERROR" if error else "DEFAULT",
+        "langfuse.observation.status_message": error or "",
         "langfuse.user.id": userId,
         "langfuse.session.id": sessionId,
         "langfuse.trace.input": input,
@@ -92,7 +98,29 @@ def trace(trace_id: str, name: str, *, userId: str = "", sessionId: str = "", in
         "langfuse.trace.tags": tags,
         **{f"langfuse.trace.metadata.{k}": v for k, v in (metadata or {}).items()},
     }
-    return _span(trace_id, name, attrs, start=start, end=end, parent=None, error=None)
+    return _span(trace_id, name, attrs, start=start, end=end, parent=None, error=error)
+
+
+def tool_span(trace_id: str, name: str, *, parent: dict, input=None, output=None, title: str = "",
+              start: str | None = None, end: str | None = None, error: str | None = None) -> dict:
+    """도구 호출 하나(SAP 조회·위키 read·grep…). 트리에서 루트 밑에 순서대로 보임."""
+    inherited = {a["key"]: a["value"].get("stringValue") for a in parent.get("attributes", [])
+                 if a["key"] in ("langfuse.user.id", "langfuse.session.id", "langfuse.trace.name", "langfuse.trace.tags")}
+    attrs = {
+        **inherited,
+        "langfuse.observation.type": "tool",
+        "langfuse.observation.input": input,
+        "langfuse.observation.output": output,
+        "langfuse.observation.level": "ERROR" if error else "DEFAULT",
+        "langfuse.observation.status_message": error or "",
+        "langfuse.observation.metadata.title": title,
+    }
+    return _span(trace_id, name, attrs, start=start, end=end, parent=parent["spanId"], error=error)
+
+
+def ms_iso(ms: int | float | None) -> str | None:
+    """OpenCode 의 epoch ms → ISO. 없으면 None(=지금)."""
+    return datetime.fromtimestamp(ms / 1000, timezone.utc).isoformat() if ms else None
 
 
 def generation(trace_id: str, name: str, *, model: str = "", input=None, output=None, usage: dict | None = None,
diff --git a/5_django_backend/tests/test_langfuse.py b/5_django_backend/tests/test_langfuse.py
index 08b8c65..d522f06 100644
--- a/5_django_backend/tests/test_langfuse.py
+++ b/5_django_backend/tests/test_langfuse.py
@@ -78,7 +78,10 @@ async def test_finalize_sends_user_trace(lf_server, django_user_model, monkeypat
     from common.opencode_service import opencode_service
 
     async def _msgs(_sid):
-        return [{"info": {"role": "assistant", "tokens": {"input": 3, "output": 4, "reasoning": 1}, "time": {"created": 1000, "completed": 1500}}, "parts": [{"type": "text", "text": "답"}]}]
+        tool = {"type": "tool", "tool": "sap-icf_get_program_source", "state": {"status": "completed", "input": {"program_name": "ZTEST"}, "output": "REPORT ztest.", "title": "ZTEST", "time": {"start": 1100, "end": 1300}}}
+        bad = {"type": "tool", "tool": "read", "state": {"status": "error", "input": {"filePath": "x"}, "error": "no such file", "time": {"start": 1300, "end": 1310}}}
+        return [{"info": {"role": "assistant"}, "parts": [tool, bad]},
+                {"info": {"role": "assistant", "tokens": {"input": 3, "output": 4, "reasoning": 1}, "time": {"created": 1000, "completed": 1500}}, "parts": [{"type": "text", "text": "답"}]}]
 
     async def _sess(_sid):
         return {"title": "MARA 조회"}
@@ -92,10 +95,15 @@ async def test_finalize_sends_user_trace(lf_server, django_user_model, monkeypat
         await asyncio.gather(*list(langfuse._pending))
     assert len(lf_server) == 1
     spans = lf_server[0]["body"]["resourceSpans"][0]["scopeSpans"][0]["spans"]
-    t, g = _attrs(spans[0]), _attrs(spans[1])
+    assert [sp["name"] for sp in spans] == ["chat", "sap-icf_get_program_source", "read"]
+    t = _attrs(spans[0])
     assert t["langfuse.user.id"] == "u@x.com" and t["langfuse.session.id"] == "ses_1"
     assert t["langfuse.trace.input"] == "질문" and t["langfuse.trace.output"] == "답"
-    assert spans[1]["parentSpanId"] == spans[0]["spanId"]
-    assert json.loads(g["langfuse.observation.usage_details"]) == {"input": 3, "output": 5, "total": 8}
-    assert g["langfuse.observation.level"] == "DEFAULT" and spans[1]["status"]["code"] == 1
+    assert t["langfuse.observation.type"] == "generation"  # 루트가 곧 답변 — 토큰은 여기
+    assert json.loads(t["langfuse.observation.usage_details"]) == {"input": 3, "output": 5, "total": 8}
+    a1, a2 = _attrs(spans[1]), _attrs(spans[2])
+    assert spans[1]["parentSpanId"] == spans[0]["spanId"] and a1["langfuse.observation.type"] == "tool"
+    assert json.loads(a1["langfuse.observation.input"]) == {"program_name": "ZTEST"} and a1["langfuse.observation.output"] == "REPORT ztest."
+    assert spans[1]["startTimeUnixNano"] == "1100000000" and spans[1]["endTimeUnixNano"] == "1300000000"
+    assert spans[2]["status"] == {"code": 2, "message": "no such file"} and a2["langfuse.observation.level"] == "ERROR"
     assert stream_mod is not None