Summary

Martin Fowler identifies November 2025 as a pivotal inflection point in AI-assisted programming, marked by the release of Anthropic's Opus 4.5 and OpenAI's GPT-5.2. He argues that Opus 4.5, combined with the Claude Code harness, crossed an invisible capability threshold that fundamentally changed how programmers work. He supports this with quotes from Simon Willison and Adam Tornhill, the latter claiming he stopped writing code by hand entirely. Fowler notes the Christmas break amplified the shift by giving busy professionals time to experiment with the new models.

Key Insight

The November 2025 AI model releases crossed an invisible capability threshold that transformed AI from a coding assistant into a viable replacement for hand-written code for many programming tasks.

Spicy Quotes (click to share)

• 1

  November 2025 marked an important point in the development of AI-assisted programming.

• 2

  The former in particular, coupled with the Claude Code harness, represented a key moment for using AI.

• 4

  one of those moments where the models get incrementally better in a way that tips across an invisible capability line where suddenly a whole bunch of much harder coding problems open up

• 7

  Sometime in late 2025, I wrote my final lines of code.

• 5

  that code wasn't written by hand. It was written by AI agents that I directed.

• 3

  For a couple of weeks people who were too busy with their day job to play with AI had the opportunity to try out these new models.

Tone

reflective