fix(mcp): isolate hosted request contexts

Author: Coding-Dev-Tools

engraphis/dashboard_app.py

@@ -382,16 +382,24 @@ def create_app() -> FastAPI:
             pass
         _prev_path = _mcp_mod.mcp.settings.streamable_http_path
         _prev_security = _mcp_mod.mcp.settings.transport_security
+        _prev_stateless = getattr(_mcp_mod.mcp.settings, "stateless_http", False)
         try:
             _mcp_mod.mcp.settings.streamable_http_path = "/"
             _mcp_mod.mcp.settings.transport_security = _mcp_transport_security(_mcp_mod.mcp)
+            # Hosted callers can bind a tenant service and principal around each HTTP
+            # operation. Stateful Streamable HTTP runs tool callbacks in the persistent
+            # initialization task, which would retain the first request's ContextVars
+            # for later requests. Stateless mode keeps every callback in its request
+            # context and is therefore required for request-scoped service isolation.
+            _mcp_mod.mcp.settings.stateless_http = True
             _mcp_asgi = _mcp_mod.mcp.streamable_http_app()
         finally:
             # streamable_http_app() captures these settings in its session manager. Restore
             # the global FastMCP instance so importing the dashboard cannot alter the
             # standalone MCP server in the same process.
             _mcp_mod.mcp.settings.streamable_http_path = _prev_path
             _mcp_mod.mcp.settings.transport_security = _prev_security
+            _mcp_mod.mcp.settings.stateless_http = _prev_stateless
         _mcp_mgr = _mcp_mod.mcp.session_manager
     except (Exception, SystemExit) as _exc:  # noqa: BLE001 - MCP mount stays optional
         import logging as _logging

tests/test_dashboard_v2.py

@@ -876,6 +876,15 @@ def test_dashboard_and_mcp_recall_share_the_v2_service(monkeypatch, tmp_path):
         assert dashboard["score_semantics"] == mcp["score_semantics"]
 
 
+def test_dashboard_mcp_mount_is_stateless_for_request_scoped_contexts(monkeypatch, tmp_path):
+    pytest.importorskip("mcp", reason="MCP extra not installed")
+    from engraphis import mcp_server
+
+    with _client(monkeypatch, tmp_path) as client:
+        assert client.app.state.mcp_over_http is True
+        assert mcp_server.mcp.session_manager.stateless is True
+
+
 def test_dashboard_keyword_fallback_reports_truthful_lexical_scores(monkeypatch, tmp_path):
     with _client(monkeypatch, tmp_path) as client:
         def mismatched_embedder(*_args, **_kwargs):