May 9, 2025 · 19m · y-combinator
How AI Coding Agents Will Change Your Job · Y Combinator
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In this episode of 'The Breakdown,' Y Combinator General Partners Dave Lieb and Tom Blomfield explore how AI coding agents are rapidly transforming software engineering, early-stage startups, and knowledge work. They address developer pushback, economic concepts like Jevons Paradox, and offer practical guidance for future founders navigating an era of technological abundance.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. How this is scored →
The partners as informed peer 5.2 Guest teaching 4.2 Guest disagreement 2.0 The partners pushing back 2.5
speaking balance: gold is the partners, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 8:45 Dividing human labor by zero
Tom emphatically rejects traditional productivity metrics, arguing that human software engineering labor will be reduced entirely to zero rather than merely leveraged.
Hardest push from the partners ▶ 8:11 Food capacity vs infinite software demandDave challenges Tom's combine harvester metaphor by arguing human demand for software is boundless compared to physical constraints on food consumption.
Biggest teaching moment ▶ 5:01 YC batch adoption data pointsTom provides concrete data on how AI coding adoption jumped from 0% to 25% across consecutive YC batches, turning abstract speculation into grounded empirical trends.
The partners hold their own ▶ 9:39 Software history from punch cards to AI abstractionDave draws on computing history to reframe AI coding not as the end of engineering, but as the latest logical abstraction layer after punch cards and OOP.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | The partners as informed peer | Guest teaching | Guest disagreement | The partners pushing back | Why |
|---|---|---|---|---|---|---|
| The Breakdown Title Card | 4 | 3 | 1 | 1 | Dave guides Tom to detail the backlash to his viral tweet comparing engineers to organic farmers. Tom shares his firsthand experience building a 35,000-line app with Claude Code without manual coding, establishing the baseline premise collaboratively. | |
| Rapid AI Tool Adoption in Startups | 5 | 4 | 2 | 2 | The hosts and guest discuss founder adoption rates and dismiss critics who call AI coding tools mere toys, citing Clay Christensen's Innovator's Dilemma to explain how toy-like tools rapidly improve. | |
| Jevons Paradox and the Future of Software | 6 | 5 | 3 | 4 | Dave pushes back on Tom's farming analogy by noting software demand is theoretically unlimited unlike caloric intake. Tom counters that software engineering labor effectively divides by zero as AI handles execution directly. | |
| Redefining the Software Engineering Job | 6 | 4 | 2 | 3 | Dave demonstrates strong domain expertise by comparing AI coding agents to earlier abstraction shifts like punch cards and OOP. Dave also explains why human product obsession remains hard for agents to replicate. | |
| AI's Impact on Knowledge Work | 5 | 5 | 2 | 3 | The discussion broadens into legal and medical knowledge work. Tom gently nuances Dave's timeline regarding professional competitive disadvantage, while Dave brings in autonomous vehicle regulation as an analog for trade protectionism. | |
| Navigating the Transition to an Abundant Future | 5 | 4 | 2 | 2 | Dave and Tom discuss the societal friction of rapid labor transitions before focusing on practical founder advice, agreeing that understanding human problems and smaller agile teams will define the next startup era. |
Statements from this episode (18)
Tom Blomfield predicts stark consequences for software engineering within 12 months
“I think we have a clear line of sight between where we are today and like improvements over the next three, six and 12 months. They're going to have quite stark consequences for software engineering, I think.”
Tom Blomfield built and migrated his entire blog in 90 minutes
“In 90 minutes on a train journey with Claude Code, and in 90 minutes I set up hosting, I wrote new blogging software, and I migrated, like, 15 years of blog posts over to a new platform.”
Tom Blomfield built a 35,000-line app without writing any code manually
“Yeah, 35,000 lines, and I wrote not a single one. And honestly, after about the first 5000 lines, I stopped even reading the code.”
Tom Blomfield says AI makes him 10x more productive than before
“These new tools made me 10 times more powerful, more productive than I was when I was kind of current in, in, you know, software engineering 10 years ago.”
Dave Lieb says up to half of YC startups primarily use AI
“I would say maybe like a third to a half of the companies would say that they pretty much primarily write code in this style.”
Tom Blomfield says AI coding in YC startups surged to 25%
“Last batch, that number was 25% of companies. So they use these tools for most of their code. Two batches ago, it was approximately zero percent.”
Dave Lieb predicts AI will eventually write any type of code
“I think it will get good enough to write any code.”
Tom Blomfield says AI will fulfill surging global demand for software
“Like I could easily see the demand goes up 10 X or a hundred X, who knows, but I just think the AI is getting so good that you just won't have humans fulfilling that demand in anything but the most niche of niche cases.”
Tom Blomfield says today's software engineering jobs will vanish within 10 years
“But the conclusion of all of that, I think, is that software engineering jobs of today, I think, will not exist in five or 10 years.”
Tom Blomfield says future engineers will primarily focus on wrangling AI machines
“I think there will be demand for smart people who know how to wrangle these AI coding machines, and if we want to call those people software engineers, so be it. But I think the job is dramatically, dramatically different.”
Tom Blomfield says software startups are reaching revenue milestones faster than ever
“So getting to a 1,000,010 million, a hundred million of revenue with a software idea had is just happening faster and faster than ever.”
Dave Lieb says AI adoption in legal and finance will become default
“And I think we're now getting to the point in legal, in finance, and all these other areas where it's become a competitive disadvantage if you don't embrace it. So I think it will become default.”
Tom Blomfield says ignoring AI will be a disadvantage within two years
“I'm not sure it's yet a competitive disadvantage, but I can imagine that becoming true in the next year or two as your tools get really, really good.”
Tom Blomfield predicts trade bodies will act as protectionists against AI
“And so I can see that happening in, in law, in medicine, as these kind of trade bodies act as gatekeepers to try and, almost like protectionist unions, trying to protect the jobs of their members.”
Tom Blomfield warns AI could displace hundreds of millions of workers
“And you could see hundreds of millions of people displaced, and the idea that they're going to retrain as in a different job, I think is going to be extremely painful. And I can see the societal impact and turmoil being very, very grave for 10 or 20 years as t…”
Tom Blomfield says early AI adopters will gain a multi-year advantage
“And if you are one of these people who are at the cutting edge of this, these tools, I think you have an advantage for several years, which will persist and enable you to frankly, to earn a lot of money to grow a great career.”
Dave Lieb says AI will improve software design by shrinking team sizes
“I think design of the products that we use, the quality of the products that we use is going to go way up because if you look at bad design or bad experiences that you encounter in your life, I think a lot of it comes from interfaces between people or between …”