Mind the Tech London 2025
Guy Podjarny unveils Tessl’s vision for AI-driven software
Ex-Snyk founder warns coding agents are unreliable, pitches “spec-driven development” as new standard.
Guy Podjarny
(Shalev Shalom)
Guy Podjarny, the Israeli entrepreneur who founded cybersecurity unicorn Snyk and is now leading a new venture, Tessl, argued at Calcalist and Bank Leumi’s Mind the Tech London 2025 conference, that artificial intelligence has the potential to transform how software is built, but warned that the industry’s current reliance on “agentic coding” is riddled with risks.
Podjarny, who co-founded Snyk in 2015 and departed the company last year after serving as CEO and then President, unveiled Tessl’s approach just hours before its official product launch. Backed by $125 million in funding from investors including Index Ventures, Accel, GV, and boldstart, Tessl is building what he describes as “spec-driven development,” a framework meant to tackle one of AI’s most pressing weaknesses: reliability.
“Agents are powerful but they’re unreliable,” Podjarny said. “They hallucinate APIs, they claim success when they’ve failed, and they jump straight into coding without clarifying intent. In software development, that’s a recipe for broken products.”
Podjarny traced the trajectory of AI in software development, from autocomplete features to integrated chat tools and now to “agentic” systems that can carry out full coding tasks independently. Gartner, he noted, has predicted that 90 percent of enterprise developers will use such tools by 2028.
But despite their promise, he warned, unchecked AI carries hidden costs. A separate Gartner estimate suggests that by 2027, a quarter of production defects could stem from AI-generated code. “We may gain speed, but if we spend all the time we saved reviewing broken code, or worse, fixing new problems, the productivity benefits disappear,” he said.
Tessl’s solution, Podjarny explained, is to require AI agents to capture intent before they write code. Instead of rushing to generate output from a short prompt, agents would first create a “spec”, a structured description of what the software should do.
These specifications, he argued, create alignment between human developers and AI, serve as a safeguard against regressions, and provide a persistent record of functionality that can outlast code itself. “We want to move from code-centric development to spec-centric development,” Podjarny said. “Agents can be powerful collaborators if we give them context and hold them accountable to clear requirements.”
Tessl is also introducing a “spec registry,” a kind of shared knowledge base that distributes best practices and compliance policies, so that agents don’t reinvent security standards or analytics frameworks from scratch.
Podjarny emphasized that Tessl’s launch is only a beginning. “This is a fast-moving space. Many things will change, many things will morph, and we believe in building in the open,” he said. “Spec-driven development is, we think, the future of software.”
