
Hosted by Lenny Rachitsky
Written by a model from the transcript; not yet reviewed.
Fiona Fung, who leads the teams behind Claude Code and CoWork at Anthropic, discusses the profound transformation of software engineering in the AI era. Drawing on her 25-year career across IBM, Microsoft, Meta, and Instagram, she explains how AI has lifted the coding bottleneck, leading to an eightfold increase in code throughput per quarter at Anthropic. Fung and Lenny Rachitsky explore the shift from synchronous tasks to async agents, the evolution of engineering management, and why the role of a software engineer is shifting toward product sense and verification.
The conversation examines what it takes to thrive as a builder when coding is no longer the primary constraint. Fung shares specific management frameworks, such as using Claude to monitor pull requests and feedback channels, balancing high agency with high accountability, and categorizing bugs into 'bad' and 'sad' outcomes. They also explore the importance of dog fooding, the rise of just-in-time planning, and how to bridge the digital divide so small businesses can benefit from AI automation.
Lenny introduces the episode and highlights the dramatic increase in code production enabled by AI tools.
Lenny welcomes Fiona Fung, outlining her extensive experience from IBM to Meta and her current role at Anthropic.
Fiona reflects on how engineering has transformed from low-level systems work to AI-assisted coding and the new challenges it brings.
Discussion of how Claude Code and Cowork enable teams to handle massive code output, focusing on verification, feedback loops, and routines.
Fiona explains the dual hiring strategy of creative builders with product sense and deep systems experts to balance innovation and reliability.
Fiona shares personal anecdotes and advice on cultivating a growth mindset to navigate the rapid changes and fears associated with AI adoption.
Exploration of how Claude Cowork helps small businesses automate knowledge work, with real-world examples and the potential for broader impact.
Fiona discusses the shift toward asynchronous agent workflows, routines, and how these abstractions will shape engineering practices in the coming years.
Discussion of how Facebook Marketplace adjusted its metrics to account for power sellers and avoid blind reliance on raw numbers.
Exploration of strategies to maintain high velocity while ensuring quality and meaningful impact in engineering teams.
Introduction of a framework distinguishing bad and sad errors to improve proactive quality monitoring across product surfaces.
The episode opens with a brief introduction and a sponsor ad from Mercury.
Anthropic Code Throughput Surgedata
Lenny notes that Anthropic engineers ship eight times as much code per quarter compared to 2025, demonstrating how AI has completely removed coding as the primary bottleneck in software development.
AI-Driven Remote Sessions for Managersstrategy
Fiona explains how she uses a Claude Code remote session hooked into all company repos, Slack channels, and metrics to review work and maintain full visibility into team output.
Small Business Onboarding with CoWorkstory
Fiona shares how small business owners use CoWork to automate tedious tasks like expensing, invoice management, and even comparative menu and market analysis.
The Shift to Asynchronous Routinesinsight
Fiona discusses how routines allow engineers and managers to use automated prompts and background agents asynchronously, moving beyond simple synchronous prompt generation.
Bad Versus Sad Frameworkstrategy
Fiona details a quality framework where teams categorize issues into 'bad' irrecoverable errors and 'sad' recoverable pain points to better track and address user experience friction.
Managers Start as Individual Contributorsstrategy
Fiona outlines her management philosophy of having new engineering leaders spend time as ICs first, writing code and using the product before taking on full personnel responsibilities.
Just-In-Time Monthly Planningstrategy
Fiona describes how her team abandoned rigid six-month roadmaps in favor of lightweight, monthly just-in-time planning to keep pace with rapid technological shifts.
“Coding is no longer the bottleneck. It's lifted the ceiling of what anyone is able to do.”
“I think, yeah, the balance, like, we're, you know, almost like two sides are the same kind of agency.”
“I love that word, agency. That's what we really hold important on the Claude Code and Cowork team.”
“And then I realized in that region, it wasn't a large number of sellers, but there were power sellers.”
“And bad is like a very bad irrecoverable error. And sad is something that's kind of like a pain point recoverable.”
“I started out like, it was for a very short, short amount of time, but, but actually this was my journey between Microsoft and Meta.”
“And then the third was another Ghibli film, Nausicaä: Valley of the Wind.”
“And that one small act of kindness can make the biggest difference.”
“I'm like, oh, no, there's this one on one that I I've been meaning to have.”
“So it's almost, almost like how, you know, sometimes people have like fidget spinners and such.”
Fiona Fung leads the teams behind Claude Code and Cowork at Anthropic (overseeing Boris Cherny and the entire engineering and PM team). Before Anthropic, she spent 11 years at Microsoft building Visual Studio and TypeScript and then moved to Meta, where she started Facebook Marketplace (now generating over $100 billion in GMV annually), worked on Meta’s first smart glasses and AR glasses, and led infrastructure, growth, integrity, and safety teams at Instagram. She’s been an engineer for over 25 years and has a unique perspective on how the role of building software is changing. *In our in-depth conversation, we discuss:* 1. What she’s learned about running a team that’s shipping 8x more code than before 2. Which roles AI will transform next 3. Specific ways her team uses AI 4. How Claude “routines” have changed how she operates as a manager 5. The context-switching problem no one has solved yet 6. The biggest unsolved problem in AI 7. What keeps her up at night *Brought to you by:* WorkOS—Make your app enterprise-ready, with SSO, SCIM, RBAC, and more: https://workos.com/lenny Mercury—Radically different banking, now with Command: https://mercury.com/ *Episode transcript:* https://www.lennysnewsletter.com/p/building-the-most-ai-pilled-engineering *Archive of all Lenny's Podcast transcripts:* https://www.dropbox.com/scl/fo/yxi4s2w998p1gvtpu4193/AMdNPR8AOw0lMklwtnC0TrQ?rlkey=j06x0nipoti519e0xgm23zsn9&st=ahz0fj11&dl=0 *Where to find Fiona Fung:* • LinkedIn: linkedin.com/in/fionafung *Where to find Lenny:* • Newsletter: https://www.lennysnewsletter.com • X: https://twitter.com/lennysan • LinkedIn: https://www.linkedin.com/in/lennyrachitsky/ *In this episode, we cover:* (00:00) Introduction to Fiona Fung (02:31) How the engineering role has transformed over 25 years (09:28) What an AI-pilled software team looks like in 2026 (12:26) Using Claude to manage and review team output (14:40) The evolution of code review and verification (16:55) Who to hire: creative builders and deep systems experts (18:18) The shift to ambitious thinking (19:40) The growth mindset required to thrive in AI-native teams (25:52) Helping small businesses adopt AI tools (31:46) How Anthropic spots latent demand and builds for it (35:08) The next frontier: asynchronous work with AI routines (38:06) Agency and accountability in AI-native teams (39:40) The vibe shift from token-maxing to ROI measurement (44:24) The “bad vs. sad” quality framework (49:34) Why all managers start as ICs at Anthropic (55:24) Preventing skill atrophy (58:43) Managing context switching with 20 AI agents running (1:00:08) How PM and data science roles are transforming (1:03:40) The importance of dogfooding and using your own product (1:08:36) Outstanding questions (1:12:48) The future of engineering jobs and education (1:17:59) What keeps Fiona up at night: team culture at scale (1:22:53) From six-month roadmaps to JIT (just-in-time) monthly planning (1:27:03) Lightning round *Referenced:* • Running an AI-native engineering org: https://www.youtube.com/watch?v=igO8iyca2_g • Head of Claude Code: What happens after coding is solved | Boris Cherny: https://www.lennysnewsletter.com/p/head-of-claude-code-what-happens • Today, Anthropic engineers on average ship 8x as much code per quarter as they did compared to 2021-2025: https://x.com/AnthropicAI/status/2062568864240836995 • Visual Studio: https://visualstudio.microsoft.com • Joseph Campbell’s quote: https://www.goodreads.com/quotes/192665-the-cave-you-fear-to-enter-holds-the-treasure-you • Life-changing Cowork use case: https://x.com/lennysan/status/2059664455001334124 • Introducing Claude for Small Business: https://www.anthropic.com/news/claude-for-small-business • Conversations with Tyler podcast: https://conversationswithtyler.com • Sheryl Sandberg on Facebook: https://www.facebook.com/sheryl# • Amélie on Prime Video: https://www.amazon.com/Amelie-Jean-Pierre-Jeunet/dp/B0DQ4S3N45 • Spirited Away on HBO Max: https://www.hbomax.com/movies/spirited-away/3deab668-d0a4-4a8d-9bc8-0952a0ad836e ... References continued at: https://www.lennysnewsletter.com/p/building-the-most-ai-pilled-engineering *Recommended books:* • Margaret Atwood’s books: https://www.amazon.com/stores/author/B000AQTHI0?ccs_id=0027a474-cd59-4a3a-bcd7-9b173c27d530 • Haruki Murakami’s books: https://www.amazon.com/stores/Haruki-Murakami/author/B000AP7AFI • The Little Prince: https://www.amazon.com/Little-Prince-Antoine-Saint-Exup%C3%A9ry/dp/0156012197 • Nausicaä of the Valley of the Wind: https://www.amazon.com/Nausica%C3%A4-Valley-Wind-Box-Set/dp/1421550644 • High Output Management: https://www.amazon.com/High-Output-Management-Andrew-Grove/dp/0679762884 _Production and marketing by https://penname.co/._ _For inquiries about sponsoring the podcast, email [email protected]._ Lenny may be an investor in the companies discussed.
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