## Summary Moves the WebRTC realtime sideband websocket join out of the voice start critical path. Call creation still posts the SDP offer and session config synchronously so the client gets the SDP answer, but the sideband websocket now connects in the input task async and doesn't block conversation state installation. This lets the normal realtime input channels buffer text, handoff output, and audio while the WebRTC sideband websocket is connecting. If the sideband join fails while the conversation is still active, the task sends a RealtimeEvent::Error through the existing events_tx / fanout path. To rephrase this: * No longer blocked on sideband: the client can receive the SDP answer earlier, set up the WebRTC peer connection, and let the media leg progress while the sideband websocket joins. * Still blocked on sideband: queued text, handoff output, and sideband server events cannot flow until connect_webrtc_sideband(...).await finishes and then run_realtime_input_task(...) starts ## Validation - `env CODEX_SKIP_VENDORED_BWRAP=1 cargo test --manifest-path codex-rs/Cargo.toml -p codex-core --test all conversation_webrtc_start_posts_generated_session` `CODEX_SKIP_VENDORED_BWRAP=1` is needed in this local environment because `libcap.pc` is not installed for the vendored bubblewrap build. ## Testing I tested this locally by running `cargo run -p codex-cli --bin codex -- --enable realtime_conversation` and invoking `/realtime`. Then, we get logs emitted in `~/.codex/log/codex-tui.log`. ### Before the Change Logging commit (c0299e6edf) ``` 2026-05-04T16:06:09.251956Z INFO session_loop{thread_id=019df3b9-e3d8-7271-b13a-b880119aa4c2}:submission_dispatch{otel.name="op.dispatch.realtime_conversation_start" submission.id="019df3bd-65df-7ee2-8125-1d6701fe39d2" codex.op="realtime_conversation_start"}: codex_core::realtime_conversation: starting realtime conversation 2026-05-04T16:06:09.251980Z INFO session_loop{thread_id=019df3b9-e3d8-7271-b13a-b880119aa4c2}:submission_dispatch{otel.name="op.dispatch.realtime_conversation_start" submission.id="019df3bd-65df-7ee2-8125-1d6701fe39d2" codex.op="realtime_conversation_start"}: codex_core::realtime_conversation: creating realtime call transport="webrtc" 2026-05-04T16:06:10.365722Z INFO session_loop{thread_id=019df3b9-e3d8-7271-b13a-b880119aa4c2}:submission_dispatch{otel.name="op.dispatch.realtime_conversation_start" submission.id="019df3bd-65df-7ee2-8125-1d6701fe39d2" codex.op="realtime_conversation_start"}: codex_core::realtime_conversation: realtime call created; sdp answer ready transport="webrtc" call_id=rtc_u0_Dbq65nhak5eLjQZ73yhAy elapsed_ms=1113 total_elapsed_ms=1113 2026-05-04T16:06:10.365843Z INFO session_loop{thread_id=019df3b9-e3d8-7271-b13a-b880119aa4c2}:submission_dispatch{otel.name="op.dispatch.realtime_conversation_start" submission.id="019df3bd-65df-7ee2-8125-1d6701fe39d2" codex.op="realtime_conversation_start"}: codex_core::realtime_conversation: connecting realtime sideband websocket call_id=rtc_u0_Dbq65nhak5eLjQZ73yhAy 2026-05-04T16:06:10.784528Z INFO session_loop{thread_id=019df3b9-e3d8-7271-b13a-b880119aa4c2}:submission_dispatch{otel.name="op.dispatch.realtime_conversation_start" submission.id="019df3bd-65df-7ee2-8125-1d6701fe39d2" codex.op="realtime_conversation_start"}: codex_core::realtime_conversation: connected realtime sideband websocket call_id=rtc_u0_Dbq65nhak5eLjQZ73yhAy elapsed_ms=418 total_elapsed_ms=1532 2026-05-04T16:06:10.784665Z INFO session_loop{thread_id=019df3b9-e3d8-7271-b13a-b880119aa4c2}:submission_dispatch{otel.name="op.dispatch.realtime_conversation_start" submission.id="019df3bd-65df-7ee2-8125-1d6701fe39d2" codex.op="realtime_conversation_start"}: codex_core::realtime_conversation: realtime conversation started ``` ### After the Change Logging commit (c8b00ac21a) ``` 2026-05-04T15:41:24.080363Z INFO ... codex_core::realtime_conversation: starting realtime conversation 2026-05-04T15:41:24.080434Z INFO ... codex_core::realtime_conversation: creating realtime call transport="webrtc" 2026-05-04T15:41:25.106906Z INFO ... codex_core::realtime_conversation: realtime call created; sdp answer ready transport="webrtc" call_id=rtc_u0_Dbpi8nhak5eLjQZ73yhAy elapsed_ms=1026 total_elapsed_ms=1026 2026-05-04T15:41:25.107067Z INFO ... codex_core::realtime_conversation: spawned realtime sideband connection task transport="webrtc" total_elapsed_ms=1026 2026-05-04T15:41:25.107160Z INFO ... codex_core::realtime_conversation: realtime conversation started 2026-05-04T15:41:25.107185Z INFO codex_core::realtime_conversation: connecting realtime sideband websocket call_id=rtc_u0_Dbpi8nhak5eLjQZ73yhAy 2026-05-04T15:41:25.107352Z INFO ... codex_core::realtime_conversation: sent realtime sdp answer to client 2026-05-04T15:41:26.076685Z INFO codex_core::realtime_conversation: connected realtime sideband websocket call_id=rtc_u0_Dbpi8nhak5eLjQZ73yhAy elapsed_ms=969 total_elapsed_ms=1996 2026-05-04T15:41:26.573893Z INFO codex_core::realtime_conversation: realtime session updated realtime_session_id=sess_u0_Dbpi8nhak5eLjQZ73yhAy 2026-05-04T15:41:26.573970Z INFO codex_core::realtime_conversation: received realtime conversation event event=SessionUpdated { ... } ``` ### Conclusion Here we see that we saved about a half a second in conversation startup (1532ms -> 969ms). This also checks out with my sanity tests; I was seeing at most a second of saving. --------- Co-authored-by: Codex <noreply@openai.com>
npm i -g @openai/codex
or brew install --cask codex
Codex CLI is a coding agent from OpenAI that runs locally on your computer.
If you want Codex in your code editor (VS Code, Cursor, Windsurf), install in your IDE.
If you want the desktop app experience, run
codex app or visit the Codex App page.
If you are looking for the cloud-based agent from OpenAI, Codex Web, go to chatgpt.com/codex.
Quickstart
Installing and running Codex CLI
Install globally with your preferred package manager:
# Install using npm
npm install -g @openai/codex
# Install using Homebrew
brew install --cask codex
Then simply run codex to get started.
You can also go to the latest GitHub Release and download the appropriate binary for your platform.
Each GitHub Release contains many executables, but in practice, you likely want one of these:
- macOS
- Apple Silicon/arm64:
codex-aarch64-apple-darwin.tar.gz - x86_64 (older Mac hardware):
codex-x86_64-apple-darwin.tar.gz
- Apple Silicon/arm64:
- Linux
- x86_64:
codex-x86_64-unknown-linux-musl.tar.gz - arm64:
codex-aarch64-unknown-linux-musl.tar.gz
- x86_64:
Each archive contains a single entry with the platform baked into the name (e.g., codex-x86_64-unknown-linux-musl), so you likely want to rename it to codex after extracting it.
Using Codex with your ChatGPT plan
Run codex and select Sign in with ChatGPT. We recommend signing into your ChatGPT account to use Codex as part of your Plus, Pro, Business, Edu, or Enterprise plan. Learn more about what's included in your ChatGPT plan.
You can also use Codex with an API key, but this requires additional setup.
Docs
This repository is licensed under the Apache-2.0 License.
