Instacart CTO: AI agents handle 97% of code, ending tech debt worries

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Instacart is posing the provocative question: What if most of the work your engineers do today should, in fact, be done by machines?

At VB Transform 2026 , CTO Anirban Kundu argued that dev teams continue to waste their time on draining, repetitive, high-volume work; this should be absorbed by AI agents so that humans can focus on problems that require judgment, intent, and exception handling.

In fact, in 97% of cases, Instacart’s builders don’t even read code anymore.

“In the past, the tactical level was the creation of the code,” Kundu said. “In the most tactical level going forward, it's going to be, ‘How do you navigate around the AI system to give you what you want?’”

AI generating code, performing "pretty serious evals"

That doesn’t mean humans never look at code; agents handle the bulk of code generation and boilerplate, particularly with newer projects where code is generated or regenerated on a weekly basis.

“The benefit of that is we don't care about tech debt anymore,” Kundu said. “Things that are not active just get dropped out and then it gets rebuilt, kind of like how we used to build assembly code or object code.”

So why not 100%? The remaining 3% is in legacy, compliance, and latency-sensitive systems and workflows, or driven by a “boatload of code” that is dead, not active, or half-active. These cases still need careful human attention.

Instacart is slowly “smoothing those parts out,” however, breaking systems down in an aptly-named project Atoms, then building them back up in a cleaner, more modular form. Kundu’s team started with the “monoliths” and is shifting to remote procedure call (RPC)-driven architectures.

But evaluation remains one of the overarching challenges. Code reviews aren’t as relevant when AI is generating code — as Kundu noted, “the lines of code are going to be correct, the syntax is going to meet your expectations” — so the goal is to move to an “intent model.” That is, training devs so they can ask different models the right questions from an intent perspective.

Evals are then performed independently: Roughly 7,000 automatic evaluations run each month, and the system answers 8,000-plus real-time developer queries with about 99.9% accuracy.

Identifying "hiccups" that human intuition might have missed

Dovetailing with this, Instacart has built an agentic site reliability engineering (SRE) system trained on years of the company’s own incidents and root-cause analyses rather than generic failure data. Instead of teaching a model how production outages work in the abstract, the team fed it the specific ways Instacart’s systems have broken over time, along with the ways humans diagnosed and fixed them.

As a result, the company has seen accuracy in detecting and mitigating production issues jump from roughly 60 to more than 90%.

Kundu pointed to one example with Instacart’s internal tool Blueberry. The AI SRE colleague watches 200-some-odd Slack channels, monitors signals, and looks for patterns across human conversations and alerts.

In one incident, a database shard backed by an EBS volume that had a “hiccup” for a period of time. The human team did not immediately suspect AWS disk issues and were “obviously scrambling” to figure out why this particular shard misbehaved.

But about 20 minutes in, Blueberry posted on Slack, pointing to a specific blip and tying it to a feature-flag-like system called "roulette" that had been inadequate. "It's supposed to be rolling out in this cadence, [but] it had been too much,” Kundu said.

Blueberry figured it out, and the team resolved the incident. “Would have a human been as quick? I think the problem is human intuition would hold us back a little bit,” Kundu said.

Humans tend to default to patterns we’ve seen before, then resort to debugging; Kundu called this the “first brain-second brain kind of thing.” But Instacart’s agentic SRE is actually “more comprehensive in its ability to look at everything and then be able to decide what does or doesn't matter.”

Redefining the engineer’s job

Looking ahead, the most tactical work for engineers will be navigating AI systems: Designing and supervising evaluation processes; coordinating multiple simultaneous experiments and features; managing constraints like limited top-of-funnel traffic for testing; figuring out when to escalate; identifying edge cases and where things might break.

Domain expertise is also being rethought in the age of AI. Instead of bottlenecking changes through a single “owner” team that touches the code, Instacart is embedding domain knowledge into definitions and specs that any team can use.

“We’ve lived in this world where this group or this engineering team is the one that can touch the code and make the modification,” said Kundu. “We're trying to move into a world where the code becomes completely democratized across groups.”