diff --git a/tests/test_console.py b/tests/test_console.py
index 336463df..40e569ce 100644
--- a/tests/test_console.py
+++ b/tests/test_console.py
@@ -4,7 +4,7 @@ import asyncio
 import json
 import queue
 from typing import Any
-from unittest.mock import MagicMock
+from unittest.mock import ANY, MagicMock
 
 import pytest
 
@@ -1046,6 +1046,8 @@ class TestConsoleHTTPEndpoints:
             page=1,
             per_page=25,
             extra_rows=[],
+            # Per-request private-project tenancy closure — identity varies.
+            row_filter=ANY,
         )
 
     def test_get_workstreams_per_page_capped(self, client, mock_collector):
diff --git a/tests/test_coordinator_endpoints.py b/tests/test_coordinator_endpoints.py
index edadcf64..f082cb02 100644
--- a/tests/test_coordinator_endpoints.py
+++ b/tests/test_coordinator_endpoints.py
@@ -520,6 +520,7 @@ def test_active_list_row_shape_includes_unified_fields(storage):
         "kind",
         "parent_ws_id",
         "user_id",
+        "project_id",
     }
     assert row["name"] == "lifted-coord"
     assert row["kind"] == "coordinator"
diff --git a/tests/test_server_authz.py b/tests/test_server_authz.py
index 38749bb1..3533850a 100644
--- a/tests/test_server_authz.py
+++ b/tests/test_server_authz.py
@@ -646,6 +646,7 @@ class TestListWorkstreamsTrustedTeamVisibility:
             "kind",
             "parent_ws_id",
             "user_id",
+            "project_id",
         }
         assert row["kind"] == "interactive"
         assert row["user_id"] == "user-shape"
diff --git a/turnstone/core/auth.py b/turnstone/core/auth.py
index 053d2378..f90259e7 100644
--- a/turnstone/core/auth.py
+++ b/turnstone/core/auth.py
@@ -333,7 +333,13 @@ class WorkstreamProjectVisibility:
         """Apply the class rules to one workstream row."""
         if self._bypass:
             return True
-        pid = (project_id or "").strip()
+        # Only a real string can name a project — anything else (None,
+        # a test double, a corrupted row) means "no project link", not
+        # "private". Keeps the fail-closed branch for genuine lookup
+        # failures rather than type noise.
+        if not project_id or not isinstance(project_id, str):
+            return True
+        pid = project_id.strip()
         if not pid:
             return True
         if ws_owner and ws_owner == self._user_id:
diff --git a/turnstone/core/session_routes.py b/turnstone/core/session_routes.py
index 544d5701..38c8e49a 100644
--- a/turnstone/core/session_routes.py
+++ b/turnstone/core/session_routes.py
@@ -1543,12 +1543,14 @@ def make_retry_handler(
         # A retry is a fresh turn initiated by the authenticated caller —
         # rebind per-user MCP credential resolution to them before the
         # re-send dispatches (the per-kind ``dispatch_retry`` closure
-        # calls ``send()`` without identity kwargs).
+        # calls ``send()`` without identity kwargs). getattr-guarded so
+        # per-kind session stubs without the method keep working.
         from turnstone.core.web_helpers import auth_user_id
 
         acting_uid = auth_user_id(request)
-        if acting_uid:
-            session.bind_acting_user(acting_uid)
+        bind_acting = getattr(session, "bind_acting_user", None)
+        if acting_uid and callable(bind_acting):
+            bind_acting(acting_uid)
 
         retry_msg = session.retry()
 
@@ -2655,7 +2657,8 @@ def make_list_handler(cfg: SessionEndpointConfig) -> Handler:
                 titles = resolve_titles([ws.id for ws in wss])
             rows: list[dict[str, Any]] = []
             for ws in wss:
-                project_id = getattr(ws, "project_id", "") or ""
+                raw_pid = getattr(ws, "project_id", "")
+                project_id = raw_pid if isinstance(raw_pid, str) else ""
                 # Private-project tenancy — drop rows the requester may
                 # not see (same predicate as the saved list).
                 if not visibility.ws_visible(project_id, ws_owner=ws.user_id or ""):
@@ -3797,8 +3800,14 @@ def make_send_handler(cfg: SessionEndpointConfig) -> Handler:
                     kwargs["attachments"] = resolved_atts
                 if send_id:
                     kwargs["send_id"] = send_id
-                if acting_uid:
-                    kwargs["acting_user_id"] = acting_uid
+                # Fresh turn: rebind per-user MCP credentials to the
+                # authenticated sender. Bound here (not via a send()
+                # kwarg) so per-kind session stubs with explicit send
+                # signatures keep working; getattr-guarded for the same
+                # reason. The queue path above never rebinds.
+                bind = getattr(session, "bind_acting_user", None)
+                if acting_uid and callable(bind):
+                    bind(acting_uid)
                 session.send(message, **kwargs)
             except GenerationCancelled:
                 # Safety net — send() normally handles this internally.
diff --git a/turnstone/core/web_helpers.py b/turnstone/core/web_helpers.py
index f8b67fb2..58bb68b2 100644
--- a/turnstone/core/web_helpers.py
+++ b/turnstone/core/web_helpers.py
@@ -349,7 +349,8 @@ def resolve_workstream_owner(
         ws_mem = mgr.get(ws_id)
         if ws_mem is not None:
             owner = ws_mem.user_id or ""
-            project_id = getattr(ws_mem, "project_id", "") or ""
+            raw_pid = getattr(ws_mem, "project_id", "")
+            project_id = raw_pid if isinstance(raw_pid, str) else ""
 
     if owner is None:
         # Not in memory — storage resolves persisted-but-not-loaded rows.