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Landmark Foundation Models · 1 min read

GPT-5: OpenAI merges fast and reasoning models into an automatic router

In one sentence OpenAI releases GPT-5 as a single model that autonomously decides when to answer fast and when to reason. Family: GPT-5, mini, nano, Pro. Default in ChatGPT, including free tier.

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After years of rumors, OpenAI ships GPT-5. But it's not just "bigger than GPT-4". It's something different: a unified system combining two previously separate things:

  • the speed of "normal" models (GPT-4o);
  • the depth of reasoning models (o1, o3).

How it works: behind the scenes, GPT-5 has a "router" deciding automatically, per query, how much to reason. Trivial question → fast answer. Hard question → think long. The user doesn't pick the model.

For ChatGPT users (free included): GPT-5 becomes the default from August 2025. Paying users get variants (mini, nano for apps, Pro for ultra-extended reasoning). Promises: fewer hallucinations, clearer writing, better code than o3. Reception is mixed: many users notice improvements, others feel "the spark" lost vs GPT-4.

Companies

OpenAI

Tools

GPT-5, GPT-5 mini, GPT-5 nano, GPT-5 Pro

Tags

OpenAIGPT-5Unified ModelRouterReasoning

Sources