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Isaac Evans

Things Isaac Says on Podcasts

Where to Find Them

Isaac Evans has been a guest on Open Source Startup Podcast and Legacy Code Rocks .

Recently: “E204: Open Source in the Age of Agents With Isaac From Semgrep” on Open Source Startup Podcast (November 2026); “Code Security and Reliability with Isaac Evans” on Legacy Code Rocks (September 2021).

What They Said

“It's not enough to spend one token more than the attacker. It's not even enough necessarily to spend 10x more than the attacker. You kind of want to know exactly which models the attacker is using and where they're looking. … If Mythos and DeepSeek are finding the exact same things, then you should just be running DeepSeek very aggressively and very expensively over most of your application.” — Isaac Evans, Open Source Startup Podcast

Calling AI vulnerability hunting a 'vulnerability slot machine' where enough tokens eventually hit a jackpot, he pushes back on the frontier labs' framing that defenders only need the best model. Defence, in his view, means matching whatever attackers can cheaply run.

Open Source Startup Podcast · 2026-11-05 Permalink → Listen →
Open Source Startup Podcast Around 34:29 into the episode
Isaac Evans

…to see way more of that. And security teams will actually get genuinely excited about, wow, like, hey, like we wanted to train the developers. Now we can just train the models to like do the things the way we know is going to actually reduce risk to the business. So that's actually really cool.

Tim Chen

…type of vendor, right? Finding issues for you, do you find yourself starting to even like invest in surface searching, like agentic research on security side for your own products? And how much you thinking that makes sense for you to invest in, given that it's an unbounded exploration space here?

Isaac Evans

Absolutely. And this is where I want to be really thoughtful because in a lot of ways, what the labs are doing, the non-charitable phrasing would be stunt hacking in the hacking community. It's like, whoa, like, look at this cool vulnerability that I found. But, you know, most companies until a year ago are not paying people to like sit there and find vulnerabilities inside their products. In fact, like most of them get really annoyed when like a Google Project Zero finds a vulnerability inside their product, right? It's like, oh, like just stop, just stop looking. Some people could have their way, like that's what we would actually do. So there's a difference between vulnerability research, which has typically been the domain of just super intelligent people. With a lot of domain expertise, and is now like models are just better vulnerability researchers than the humans themselves. I think a difference between that and security engineering, where security engineering is much more about we know there are going to be vulnerabilities rather than finding them all. What are we doing to actually reduce their impact to like decrease the statistical probability of them appearing to…

Speaker 3

That is interesting because you can kind of say, okay, like obviously LLMs are very new. The ability to use tokens to find vulnerabilities is new, but you could have also just hired and like spent a ton of money to find these before too. It was just a human labor problem. Right. It is interesting…

Isaac Evans

I mean, I think I am learning more from founder friends, right, who are like founding companies today. Some of the things that I'm learning from them are like, you know, the importance of like capturing the traces and like doing analysis on like the traces and the intention behind the developer…

Speaker 3

Super interesting. And I'm so happy that we had you on because I think this is one of the most important topics. You're kind of at the like middle of a lot of the security conversations going around agents and AI. So, thank you so much for doing this with us, Isaac.

Speaker names come from our own diarization. The position is estimated from where the line sits in the episode.
“One of the projects that we reported vulnerabilities to got so many vulnerability reports, they decided to just stop publishing the source for their application. … The narrative they told was, hey, the existence of powerful models that can just take source code and turn it into vulnerabilities means that it is a liability for us now to have our source code out here. At first, I thought that was a little bit ridiculous. I will say that I think things are definitely changing.” — Isaac Evans, Open Source Startup Podcast

Asked how open source plays out in the AI era, the Semgrep CEO says an early-access frontier model used with Semgrep's tooling found many bugs in an open source project. The project responded by going closed source.

Open Source Startup Podcast · 2026-11-05 Permalink → Listen →
Open Source Startup Podcast Around 11:30 into the episode
Isaac Evans

…want to think about how we can actually get in positive control of some of these security properties and generalize from, hey, like, here's one way in which we were hacked, all the way back to what's the root cause of that, and how can we prevent that from ever being in our systems going forward?

Tim Chen

…in. I'm very curious about how this is not just a way to have contribution and also community be involved. I feel like in today's AI world, this is quite a new, a possible way to either find more value for users or for agents. So, I'm very curious, like, what is that continuation for you as well?

Isaac Evans

…lot. And so, I was really excited to talk about that with you both in particular. I have two stories that I think are really telling. One of them is actually: we had early access to one of the big model releases a couple of months ago. And we, along with a couple of other people who had early access, used it to find in conjunction with our existing tooling a bunch of interesting vulnerabilities. One of the projects that we reported vulnerabilities to got so many vulnerability reports, they decided to just stop publishing the source for their application. They were like, and they probably had some other go-to-market reasons to do this. I don't really know, right? The narrative they told was, hey, like the existence of powerful models that can just take source code and turn it into vulnerabilities means that it is a liability for us now to have our source code out here for this application. So we're going closed source. At first, I thought that…

Speaker 3

Yeah, I'm super interested. So I guess like a few questions and thoughts coming out of that. Like, do you have to be open source to be a successful developer application security company is one. And or does Semgrep have enough trust already in the ecosystem that you can close source new products…

Isaac Evans

that's a great question. We don't want to like closed source like any of the stuff that we've offered so far. You may know like two years ago, we changed the license for the SymGret rules and we took some stuff out of the open source engine offering, even though the license was still LGPL. That was…

Speaker 3

I think it's a really hard problem because traditional open source licenses were very much centered around like distribution, copying code, but training on code is like such a different thing. And how do you enforce that? And also I think the regulatory bodies at B are not up to date with how to…

Speaker names come from our own diarization. The position is estimated from where the line sits in the episode.

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