Model family timeline
Last updated Feb 5, 2026
GPT-5 Codex model releases
A source-backed timeline for the GPT-5 Codex model family, collecting release dates, labs, access details, context windows, and major lifecycle changes.
Most recent in this set
2 models
GPT-5.3-Codex
AvailableOpenAI's February 2026 Codex update, optimized for agentic software engineering in ChatGPT, Codex, and the API. GPT-5.3-Codex improves code quality, patch reliability, repository-scale reasoning, and long-running autonomous coding workflows while keeping the 400K-token input context and 128K-token output limit of the Codex line.
GPT-5.2-Codex
AvailableOpenAI's December 2025 Codex model for agentic coding, released after GPT-5.2 with stronger repository understanding, code generation, and tool-use behavior for software engineering agents. The API model is listed with a 400K-token input context, 128K-token output limit, and $1.25 / $10 per million input/output tokens.