Mux is an internal multi-agent coding tool that started when one engineer built it to solve their own problem. The idea was minimal: each agent gets its own git worktree, its own branch, its own terminal. No conflicts. No stashing.
CoinbasePublished by the organization itself (post), no named author
Post: Coding Had a Concurrency Problem: How Mux Helped Solve It, Coinbase engineering blog (byline: Alessandro Rodi, Adam Wolf), May 11, 2026, at The Evidence: Mux.
Checked against the source by a first reader, then confirmed independently by a second reader who fetched the source without seeing the first reader's notes (Independent review agent (Claude Sonnet), blind second pass from passage text and citation only, no repository access, 2026-11-04).
Verbatim match in the Wayback copy (live page blocked by bot challenge). First-party Coinbase text.
Coinbase, “Coding Had a Concurrency Problem: How Mux Helped Solve It”, Coinbase engineering blog (byline: Alessandro Rodi, Adam Wolf), 2026-05-11, at The Evidence: Mux. https://coinbase.com/blog/coding-had-a-concurrency-problem-how-mux-helped-solve-it Archived at https://the-ai-record.com/passages/coinbase-mux-internal-multi-agent-coding-tool-started-2026
600+ users including engineers, PMs, and designers, with 335 active and 197 power users. 5,068 merged PRs across 461 repositories and 10 orgs. 3.5x more merged PRs per engineer for Mux users compared to baseline: 39.6 vs 11.4.
CoinbasePublished by the organization itself (post), no named author
Post: Coding Had a Concurrency Problem: How Mux Helped Solve It, Coinbase engineering blog (byline: Alessandro Rodi, Adam Wolf), May 11, 2026, at The Evidence: Mux.
AI changed the build-vs-buy calculus for internal tooling. Before AI, building something like Mux internally would have meant vendor evaluations, procurement, and months of negotiation. Now, one engineer with access to the right models and infrastructure can prototype in days what used to require a vendor relationship.
CoinbasePublished by the organization itself (post), no named author
Post: Coding Had a Concurrency Problem: How Mux Helped Solve It, Coinbase engineering blog (byline: Alessandro Rodi, Adam Wolf), May 11, 2026, at What About Open Source?.
One engineer might have three or four agents working in parallel: one implementing an API, one writing integration tests, one fixing a bug, one refactoring a legacy module. The engineer reviews each as it finishes, provides feedback, and merges.
CoinbasePublished by the organization itself (post), no named author
Post: Coding Had a Concurrency Problem: How Mux Helped Solve It, Coinbase engineering blog (byline: Alessandro Rodi, Adam Wolf), May 11, 2026, at The Shift.
These numbers come with caveats. Mux users likely skew toward engineers who were already high-output and AI-forward, so we don't claim Mux is the sole cause. But the consistency across orgs and repos suggests this isn't a marginal effect.
CoinbasePublished by the organization itself (post), no named author
Post: Coding Had a Concurrency Problem: How Mux Helped Solve It, Coinbase engineering blog (byline: Alessandro Rodi, Adam Wolf), May 11, 2026, at The Evidence: Mux.
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