Jarred Sumner
Creator of Bun
The creator of Bun, the fast JavaScript runtime, sold his company to Anthropic in its first-ever acquisition — convinced that as AI writes ever more code, the runtime and tooling underneath it “become way more important.”
In his words
If most new code is going to be written, tested, and deployed by AI agents… the runtime and tooling become way more important.
I started using Claude Code myself. I got kind of obsessed with it.
Biography
Jarred Sumner is the creator of Bun, an all-in-one JavaScript runtime, bundler, test runner, and package manager designed to be dramatically faster than the incumbents. He founded Bun in 2021 and built the company Oven around it, becoming a prominent figure in the JavaScript ecosystem.
Bun joins Anthropic
In December 2025, Anthropic acquired Oven — reportedly its first acquisition — because Bun had become critical infrastructure: Claude Code ships as a Bun executable, and, in Sumner’s words, “if Bun breaks, Claude Code breaks.” He describes getting “obsessed” with Claude Code and deciding that “betting on Anthropic sounded like a more interesting path” than raising venture money and chasing monetization on his own.
His thesis is about where value moves as AI writes more software: the runtimes, CLIs, and tooling that agents rely on to execute code become more important, not less. Bun’s team leaned into this by using Claude heavily in Bun’s own development — an aggressive approach that drew criticism when the creator of the Zig language dismissed a Claude-driven Rust rewrite as “unreviewed slop.”
Where they stand in the war
Who backs them up
Sources & further reading
Canonical record: https://battlelines.ai/topic/jarred-sumner