Bio
Simon Willison's foundational contribution is the taxonomy of how professionals actually work with LLMs, distinguishing between "vibe coding" (fast, loose, prompt-driven, no accountability for how code works) and what he initially called "vibe engineering" before settling on "agentic engineering" -- where seasoned professionals accelerate their work with LLMs while staying accountable for production-quality output. This distinction matters because it clarifies that the highest-value use of AI is not replacing expertise but amplifying it.
Operating themes
- Operating thesis: AI tools amplify existing expertise -- the more skills and experience you bring, the better results you get -- and the discipline of working with coding agents is closer to engineering management than to programming.
- Building With Llms
- Prompt Engineering
- Agentic Ai Design
Cards
- November 2025 was the qualitative threshold — coding agents now almost always do what you tell them — Coding agents crossed the "almost always works" threshold in Nov 2025 [Tier A]
- The dark factory: nobody reads the code, gated by a simulated QA swarm — Nobody types or reads code; simulated QA swarm gates correctness [Tier A]
- Hoard a personal repository of things that worked — coding agents will recombine them — Hoard a personal repo of working artifacts; the agent recombines them [Tier A]
- Encode jargon shorthand once, save tokens forever — Encode jargon shorthand once, save tokens forever [Tier B]
Sources captured
- 2026-04-02 — Lenny's Podcast, "Agentic engineering and the November inflection" (
raw/podcasts/simon-willison--agentic-engineering-november-inflection--2026-04-02.md) - 2026-04 —
heres-how-i-use-llms-to-help-me-write-code.md(operator essay archive) - 2026-04 —
vibe-engineering.md(operator essay archive) - 2026-04 —
agentic-engineering-patterns-simon-willisons-weblog.md(operator essay archive)