Block I · Foundations · Lesson 1
From 2023 to today: how much AI has changed (and what hasn't)
We look at how we went from a chat that forgot everything within minutes to agents that work alone for hours, use the computer and read entire documents. You'll see which advances are real, which are marketing and which limits are still the same, so you know what you can expect from AI today.
- 10 min
- 9 animated slides
- 4-question quiz
- Narrated in 6 languages
What you'll see in this lesson
- 2023: a brilliant chat, but locked in
GPT-4 arrived in March 2023: it wrote very well, but it could only work with what you pasted into the chat.
- From twelve pages to several books of context
The context window has gone from 8,000 tokens in GPT-4 to one million in the top models of 2026.
- The four leaps that are real
Between 2024 and 2025 AI gained voice and sight, learned to think before speaking and to use the computer, and an open reasoner arrived.
- Agents that last for hours of work
In 2023, GPT-4 completed half of the tasks of about 4 minutes; in early 2026, Claude Opus 4.6, those of about 12 hours.
- Using the computer: from 12% to 85%
In OSWorld, a test with real tasks on a computer, AI went from 12% in 2024 to about 85% by mid-2026.
- 2023 versus today, at a glance
It doesn't just write better: now it sees, hears, reasons, uses tools and costs much less per token.
- What's marketing (or close to it)
Almost all the figures are true, but they're told in the most flattering way. Learn to read the fine print.
- What hasn't changed: it still makes things up
2026 models make far fewer mistakes, but they still state false facts with the same confidence as true ones.
- Summary: what to expect from AI today
Much more capable than in 2023, but not infallible: delegate more than before and review as much as ever.
Tools and concepts
- GPT-6
- Claude Opus 5.5
- Gemini 3.8
- DeepSeek V4
- OSWorld
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