diff --git a/apps/api/src/services/approval_db.py b/apps/api/src/services/approval_db.py
index 42ea38166..b2e664bf4 100644
--- a/apps/api/src/services/approval_db.py
+++ b/apps/api/src/services/approval_db.py
@@ -1120,11 +1120,12 @@ class TimelineDBService:
         risk_level: str | None = None,
         approval_id: str | None = None,
         incident_id: str | None = None,
+        project_id: str | None = None,
     ) -> dict[str, Any]:
         """
         新增時間軸事件
         """
-        async with get_db_context() as db:
+        async with get_db_context(project_id) as db:
             event = TimelineEvent(
                 event_type=event_type,
                 status=status,
diff --git a/apps/api/src/services/incident_memory.py b/apps/api/src/services/incident_memory.py
index 750cd1018..01a226002 100644
--- a/apps/api/src/services/incident_memory.py
+++ b/apps/api/src/services/incident_memory.py
@@ -97,6 +97,8 @@ def _derive_incident_alert_metadata(incident: Incident) -> dict[str, Any]:
 async def _add_signal_timeline_event(
     incident: Incident,
     metadata: dict[str, Any],
+    *,
+    project_id: str,
 ) -> None:
     """Best-effort timeline seed for incidents created outside Alertmanager."""
     alertname = metadata.get("alertname")
@@ -115,6 +117,7 @@ async def _add_signal_timeline_event(
             actor_role="signal_worker",
             risk_level=getattr(incident.severity, "value", incident.severity),
             incident_id=incident.incident_id,
+            project_id=project_id,
         )
     except Exception as exc:
         logger.warning(
@@ -137,10 +140,13 @@ class IncidentDbAdapter:
               注入到 lewooogo-brain 的 DualIncidentMemory
     """
 
+    def __init__(self, project_id: str = "awoooi") -> None:
+        self._project_id = project_id
+
     async def load(self, incident_id: str) -> Incident | None:
         """從 PostgreSQL 載入 Incident"""
         try:
-            async with get_db_context() as db:
+            async with get_db_context(self._project_id) as db:
                 from sqlalchemy import select
                 stmt = select(IncidentRecord).where(
                     IncidentRecord.incident_id == incident_id
@@ -161,7 +167,7 @@ class IncidentDbAdapter:
         metadata = _derive_incident_alert_metadata(incident)
         created = False
         try:
-            async with get_db_context() as db:
+            async with get_db_context(self._project_id) as db:
                 from sqlalchemy import select
 
                 stmt = select(IncidentRecord).where(
@@ -191,6 +197,7 @@ class IncidentDbAdapter:
                 else:
                     record = IncidentRecord(
                         incident_id=incident.incident_id,
+                        project_id=self._project_id,
                         status=incident.status.value,
                         severity=incident.severity.value,
                         signals=[
@@ -222,7 +229,11 @@ class IncidentDbAdapter:
                     created = True
 
             if created:
-                await _add_signal_timeline_event(incident, metadata)
+                await _add_signal_timeline_event(
+                    incident,
+                    metadata,
+                    project_id=self._project_id,
+                )
             logger.debug("db_adapter_save_success", incident_id=incident.incident_id)
             return True
 
diff --git a/apps/api/src/services/signal_observation_service.py b/apps/api/src/services/signal_observation_service.py
index 98e3cd8a4..12359f1c3 100644
--- a/apps/api/src/services/signal_observation_service.py
+++ b/apps/api/src/services/signal_observation_service.py
@@ -436,6 +436,7 @@ async def _add_observation_timeline(
             actor_role="signal_worker",
             risk_level=_severity_value(getattr(incident, "severity", None)),
             incident_id=_incident_id(incident),
+            project_id=PROJECT_ID,
         )
     except Exception as exc:
         logger.warning(
@@ -477,7 +478,10 @@ async def _ensure_signal_observation_mcp_runtime() -> None:
     try:
         from src.plugins.mcp.providers import register_all_providers
         from src.plugins.mcp.registry import get_provider_registry
-        from src.services.mcp_tool_registry import get_mcp_tool_registry, init_mcp_tool_registry
+        from src.services.mcp_tool_registry import (
+            get_mcp_tool_registry,
+            init_mcp_tool_registry,
+        )
 
         provider_registry = get_provider_registry()
         if len(provider_registry) == 0:
diff --git a/apps/api/tests/test_incident_memory_adapter.py b/apps/api/tests/test_incident_memory_adapter.py
index 0ce7a60e8..5c21dd5d7 100644
--- a/apps/api/tests/test_incident_memory_adapter.py
+++ b/apps/api/tests/test_incident_memory_adapter.py
@@ -1,9 +1,16 @@
 from __future__ import annotations
 
+from contextlib import asynccontextmanager
 from types import SimpleNamespace
 
+import pytest
+
 from src.models.incident import Severity
-from src.services.incident_memory import _derive_incident_alert_metadata
+from src.services import incident_memory as incident_memory_module
+from src.services.incident_memory import (
+    IncidentDbAdapter,
+    _derive_incident_alert_metadata,
+)
 
 
 def test_signal_worker_incident_metadata_uses_signal_alert_name() -> None:
@@ -30,3 +37,31 @@ def test_signal_worker_incident_metadata_uses_signal_alert_name() -> None:
     assert metadata["description"] == "29 ERROR log entries in last 5min"
     assert metadata["actor"] == "journal"
 
+
+@pytest.mark.asyncio
+async def test_incident_db_adapter_uses_explicit_project_context(monkeypatch) -> None:
+    project_ids: list[str | None] = []
+
+    class FakeResult:
+        def scalar_one_or_none(self):
+            return None
+
+    class FakeDb:
+        async def execute(self, _statement):
+            return FakeResult()
+
+    @asynccontextmanager
+    async def fake_get_db_context(project_id=None):
+        project_ids.append(project_id)
+        yield FakeDb()
+
+    monkeypatch.setattr(
+        incident_memory_module,
+        "get_db_context",
+        fake_get_db_context,
+    )
+
+    result = await IncidentDbAdapter(project_id="awoooi").load("INC-NOT-FOUND")
+
+    assert result is None
+    assert project_ids == ["awoooi"]
diff --git a/apps/api/tests/test_signal_observation_service.py b/apps/api/tests/test_signal_observation_service.py
index 9a34281d7..8f3401745 100644
--- a/apps/api/tests/test_signal_observation_service.py
+++ b/apps/api/tests/test_signal_observation_service.py
@@ -2,7 +2,10 @@ from __future__ import annotations
 
 from types import SimpleNamespace
 
+import pytest
+
 from src.models.incident import Severity
+from src.services import signal_observation_service as signal_observation_module
 from src.services.signal_observation_service import (
     build_signal_worker_provider_event_id,
     enrich_incident_for_signal_observation,
@@ -72,3 +75,26 @@ def test_signal_worker_event_content_is_operator_readable() -> None:
     assert "Incident: INC-20260518-TEST01" in content
     assert "Alert: HostErrorLogFlood" in content
     assert "Telegram: not sent" in content
+
+
+@pytest.mark.asyncio
+async def test_signal_observation_timeline_uses_explicit_project_context(monkeypatch) -> None:
+    calls: list[dict] = []
+
+    class FakeTimelineService:
+        async def add_event(self, **kwargs):
+            calls.append(kwargs)
+
+    monkeypatch.setattr(
+        "src.services.approval_db.get_timeline_service",
+        lambda: FakeTimelineService(),
+    )
+
+    await signal_observation_module._add_observation_timeline(
+        incident=_host_incident(),
+        signal_data={"alert_name": "HostErrorLogFlood"},
+        labels={"target": "ollama"},
+        raw_evidence_created=True,
+    )
+
+    assert calls[0]["project_id"] == "awoooi"