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Models·OpenAI·Aug 2025

★34. GPT-5 / Codex CLI / Research Agent

The convergence of scale and reasoning

Product Announcement
Summary

Released GPT-5, unifying the GPT and o-series into a single model with auto/fast/thinking modes. Replaced GPT-4o, o3, o4-mini, and GPT-4.1 as the new default in ChatGPT, representing the convergence of scale and reasoning.

Key Concepts

Merged GPT and o-series into one model with Auto/Fast/Thinking modes

GPT-5 combined the broad knowledge and fast inference of the GPT series with the reasoning capabilities of the o-series. Users could choose between "Auto" (model decides how much to think), "Fast" (optimized for speed), and "Thinking" (extended reasoning) modes.

One model replaces GPT-4o, GPT-4.1, o3, and o4-mini in ChatGPT

GPT-5 replaced GPT-4o, GPT-4.1, GPT-4.1 mini, o3, and o4-mini in ChatGPT. One model for everything.

Full text, image, audio, and video I/O in a single architecture

Full text, image, audio, and video input/output in a single model.

GPT-5 available directly from the command line for developer coding tasks

Developers could use GPT-5 directly from the command line for coding tasks.

Connections

34. GPT-5 / Codex CL…Aug 202533. Introducing o3 a…Apr 202536. Introducing gpt-…Aug 2025Influenced byInfluences
Influenced by
33. Introducing o3 and o4-mini
Apr 2025
Influences
36. Introducing gpt-oss
Aug 2025