Move workspace roots onto thread/session state and stop using active permission profile modifications as an overlay for writable roots. Existing app-server threads now preserve their persisted PermissionProfile value across resume, fork, and turn updates; permissions requests on existing threads only update the active named profile after validating it exists. Workspace roots can be updated independently, and SandboxPolicy::WorkspaceWrite no longer stores its own writable_roots.

sdk/python/tests/test_public_api_signatures.py

@@ -70,6 +70,7 @@ def test_generated_public_signatures_are_snake_case_and_typed() -> None:
             "service_name",
             "service_tier",
             "session_start_source",
+            "thread_source",
         ],
         Codex.thread_list: [
             "archived",
@@ -108,6 +109,7 @@ def test_generated_public_signatures_are_snake_case_and_typed() -> None:
             "model_provider",
             "sandbox",
             "service_tier",
+            "thread_source",
         ],
         Thread.turn: [
             "approval_policy",
@@ -148,6 +150,7 @@ def test_generated_public_signatures_are_snake_case_and_typed() -> None:
             "service_name",
             "service_tier",
             "session_start_source",
+            "thread_source",
         ],
         AsyncCodex.thread_list: [
             "archived",
@@ -186,6 +189,7 @@ def test_generated_public_signatures_are_snake_case_and_typed() -> None:
             "model_provider",
             "sandbox",
             "service_tier",
+            "thread_source",
         ],
         AsyncThread.turn: [
             "approval_policy",