OpenAI Codex CLI Ships GPT-5.3-Codex-Spark at 1,000+ Tokens/Sec, Windows OS-Level Sandboxing, and Realtime Voice v2 WebRTC Default

OpenAI Developers·medium signal

OpenAI Codex CLI's April updates include a purpose-built GPT-5.3-Codex-Spark model running at 1,000+ tokens per second for rapid iteration loops, native Windows sandbox with OS-level networking isolation, and realtime voice sessions defaulting to the v2 WebRTC path with configurable transport and voice selection. MCP support expanded with resource reads, tool-call metadata, custom-server tool search, server-driven elicitations, and file-parameter uploads. The /resume command can now jump directly to a session by ID from the TUI. Signal for builders: Codex CLI is becoming a full agent runtime, not just a coding assistant.