codex/sdk/python

Codex App Server Python SDK (Experimental)

Experimental Python SDK for codex app-server JSON-RPC v2 over stdio, with a small default surface optimized for real scripts and apps.

The generated wire-model layer is currently sourced from the bundled v2 schema and exposed as Pydantic models with snake_case Python fields that serialize back to the app-server’s camelCase wire format.

Install

cd sdk/python
python -m pip install -e .

Published SDK builds pin an exact codex-cli-bin runtime dependency. For local repo development, either pass AppServerConfig(codex_bin=...) to point at a local build explicitly, or use the repo examples/notebook bootstrap which installs the pinned runtime package automatically.

Quickstart

from codex_app_server import Codex

with Codex() as codex:
    thread = codex.thread_start(model="gpt-5")
    result = thread.run("Say hello in one sentence.")
    print(result.final_response)
    print(len(result.items))

result.final_response is None when the turn completes without a final-answer or phase-less assistant message item.

Docs map

• Golden path tutorial: docs/getting-started.md
• API reference (signatures + behavior): docs/api-reference.md
• Common decisions and pitfalls: docs/faq.md
• Runnable examples index: examples/README.md
• Jupyter walkthrough notebook: notebooks/sdk_walkthrough.ipynb

Examples

Start here:

cd sdk/python
python examples/01_quickstart_constructor/sync.py
python examples/01_quickstart_constructor/async.py

Runtime packaging

The repo no longer checks codex binaries into sdk/python.

Published SDK builds are pinned to an exact codex-cli-bin package version, and that runtime package carries the platform-specific binary for the target wheel.

For local repo development, the checked-in sdk/python-runtime package is only a template for staged release artifacts. Editable installs should use an explicit codex_bin override for manual SDK usage; the repo examples and notebook bootstrap the pinned runtime package automatically.

Maintainer workflow

cd sdk/python
python scripts/update_sdk_artifacts.py generate-types
python scripts/update_sdk_artifacts.py \
  stage-sdk \
  /tmp/codex-python-release/codex-app-server-sdk \
  --runtime-version 1.2.3
python scripts/update_sdk_artifacts.py \
  stage-runtime \
  /tmp/codex-python-release/codex-cli-bin \
  /path/to/codex \
  --runtime-version 1.2.3

This supports the CI release flow:

• run generate-types before packaging
• stage codex-app-server-sdk once with an exact codex-cli-bin==... dependency
• stage codex-cli-bin on each supported platform runner with the same pinned runtime version
• build and publish codex-cli-bin as platform wheels only; do not publish an sdist

Compatibility and versioning

• Package: codex-app-server-sdk
• Runtime package: codex-cli-bin
• Current SDK version in this repo: 0.2.0
• Python: >=3.10
• Target protocol: Codex app-server JSON-RPC v2
• Recommendation: keep SDK and codex CLI reasonably up to date together

Notes

• Codex() is eager and performs startup + initialize in the constructor.
• Use context managers (with Codex() as codex:) to ensure shutdown.
• Prefer thread.run("...") for the common case. Use thread.turn(...) when you need streaming, steering, or interrupt control.
• For transient overload, use codex_app_server.retry.retry_on_overload.