OpenAI Codex app adds GPT-5.3-Codex-Spark model and conversation forking
OpenAI's Codex app release notes announce support for a new model variant, GPT-5.3-Codex-Spark, alongside UX features including conversation forking and a floating pop-out window. Windows alpha testing is also beginning. The update signals continued iteration on a specialized coding-focused model tier within the GPT-5 family.
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Introducing GPT-5.3-Codex-Spark
OpenAI has announced GPT-5.3-Codex-Spark, described as their first real-time coding model. It offers 15x faster generation compared to prior coding models and supports a 128k context window. The model is currently available in research preview for ChatGPT Pro subscribers.
OpenAI Codex app adds GPT-5.3-Codex model, mid-turn steering, and file attachments
OpenAI released updates to the Codex app introducing support for GPT-5.3-Codex, a new mid-turn steering capability allowing users to redirect the model while it is actively working, and support for arbitrary file attachments. Mid-turn steering is a notable agentic UX feature that enables real-time human-in-the-loop intervention during long-running tasks. The release also includes a minor UI bug fix.
OpenAI releases GPT-5.3-Codex, upgraded agentic coding model with faster inference and real-time steering
OpenAI released GPT-5.3-Codex, an incremental upgrade to GPT-5.2-Codex targeting complex software engineering tasks. The new model runs 25% faster, improves reasoning and professional knowledge, and adds better real-time collaboration features including progress updates and in-session steering. It is available immediately across ChatGPT paid plans via the Codex app, CLI, IDE extension, and Codex Cloud, with API access forthcoming.
OpenAI releases GPT-5.4 in Codex with native computer-use and 1M context window
OpenAI has made GPT-5.4 available across all Codex surfaces — the app, CLI, IDE extension, and Codex Cloud — positioning it as the recommended model for most Codex tasks. GPT-5.4 is the first general-purpose model in Codex with native computer-use capabilities and experimental support for a 1M token context window. The release also includes stronger tool use and tool search for agentic workflows, and the model is available via API.
OpenAI Codex app adds conversation forking and model-switching slash commands
OpenAI's Codex app received a feature update adding conversation forking from arbitrary earlier messages, slash commands for switching models and reasoning levels mid-draft, and plan-mode notifications. Bug fixes address thread handoff and subagent navigation issues in worktrees and the VS Code extension. The update reflects ongoing iteration on agentic coding UX patterns.
OpenAI releases GPT-5.3-Codex-Spark, a real-time coding model exceeding 1000 tokens/second via Cerebras partnership
OpenAI launched a research preview of GPT-5.3-Codex-Spark, a smaller, latency-optimized variant of GPT-5.3-Codex targeting real-time coding workflows at over 1000 tokens per second. The release is available to ChatGPT Pro users via the Codex app, CLI, and IDE extension, but not yet through the API. It marks the first public milestone of OpenAI's partnership with Cerebras, whose inference hardware enables the high-throughput performance. The model is text-only with a 128k context window and operates under separate usage limits during the research preview.
Introducing GPT-5.3-Codex
OpenAI has announced GPT-5.3-Codex, described as a Codex-native agent combining frontier coding performance with general reasoning capabilities. The model is designed to support long-horizon, real-world technical work. The announcement positions it as an agentic coding system rather than a standalone language model.
OpenAI releases GPT-5-Codex: GPT-5 variant optimized for agentic coding
OpenAI has published an addendum to the GPT-5 system card introducing GPT-5-Codex, a version of GPT-5 specifically optimized for agentic coding within the Codex environment. The model features dynamic thinking-effort adjustment, scaling compute based on task complexity—responding quickly to simple queries while sustaining longer independent work on complex coding tasks. This represents a specialized derivative of GPT-5 targeting software engineering agents rather than general-purpose use.