## Why
The Python SDK previously protected the stdio transport with a single
active turn-consumer guard. That avoided competing reads from stdout,
but it also meant one `Codex`/`AsyncCodex` client could not stream
multiple active turns at the same time. Notifications could also arrive
before the caller received a `TurnHandle` and registered for streaming,
so the SDK needed an explicit routing layer instead of letting
individual API calls read directly from the shared transport.
## What Changed
- Added a private `MessageRouter` that owns per-request response queues,
per-turn notification queues, pending turn-notification replay, and
global notification delivery behind a single stdout reader thread.
- Generated typed notification routing metadata so turn IDs come from
known payload shapes instead of router-side attribute guessing, with
explicit fallback handling for unknown notification payloads.
- Updated sync and async turn streaming so `TurnHandle.stream()`/`run()`
and `stream_text()` consume only notifications for their own turn ID,
while `AsyncAppServerClient` no longer serializes all transport calls
behind one async lock.
- Cleared pending turn-notification buffers when unregistered turns
complete so never-consumed turn handles do not leave stale queues
behind.
- Removed the internal stream-until helper now that turn completion
waiting can register directly with routed turn notifications.
- Updated Python SDK docs and focused tests for concurrent transport
calls, interleaved turn routing, buffered early notifications, unknown
notification routing, async delegation, and routed turn completion
behavior.
## Validation
- `uv run --extra dev ruff format scripts/update_sdk_artifacts.py
src/codex_app_server/_message_router.py src/codex_app_server/client.py
src/codex_app_server/generated/notification_registry.py
tests/test_client_rpc_methods.py
tests/test_public_api_runtime_behavior.py
tests/test_async_client_behavior.py`
- `uv run --extra dev ruff check scripts/update_sdk_artifacts.py
src/codex_app_server/_message_router.py src/codex_app_server/client.py
src/codex_app_server/generated/notification_registry.py
tests/test_client_rpc_methods.py
tests/test_public_api_runtime_behavior.py
tests/test_async_client_behavior.py`
- `uv run --extra dev pytest tests/test_client_rpc_methods.py
tests/test_public_api_runtime_behavior.py
tests/test_async_client_behavior.py`
- `git diff --check`
---------
Co-authored-by: Codex <noreply@openai.com>
## TL;DR
WIP esp the examples
Thin the Python SDK public surface so the wrapper layer returns
canonical app-server generated models directly.
- keeps `Codex` / `AsyncCodex` / `Thread` / `Turn` and input helpers,
but removes alias-only type layers and custom result models
- `metadata` now returns `InitializeResponse` and `run()` returns the
generated app-server `Turn`
- updates docs, examples, notebook, and tests to use canonical generated
types and regenerates `v2_all.py` against current schema
- keeps the pinned runtime-package integration flow and real integration
coverage
## Validation
- `PYTHONPATH=sdk/python/src python3 -m pytest sdk/python/tests`
- `GH_TOKEN="$(gh auth token)" RUN_REAL_CODEX_TESTS=1
PYTHONPATH=sdk/python/src python3 -m pytest sdk/python/tests -rs`
---------
Co-authored-by: Codex <noreply@openai.com>
