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Will Larson

@lethain.com

Write at lethain.com. Author of An Elegant Puzzle, Staff Engineer, and An Engineering Executive’s Primer. Worked some places.

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21.10.2024
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Latest posts by Will Larson @lethain.com

Our workflows are relatively simple, so usually the issue here is large files associated with the workflows, which are we’ve mostly solved by using subagents for file processing.

Beyond that our compaction strategy is literally “use a leaked version of Claude code’s compaction prompt” after 80%

03.01.2026 21:00 👍 2 🔁 0 💬 0 📌 0
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Building internal agents A few weeks ago in Facilitating AI adoption at Imprint, I mentioned our internal agent workflows that we are developing. This is not the core of Imprint–our core is powering co-branded credit card pro...

Wrote up a series of nine short posts on interesting problems we encountered while building an internal agent framework (virtual files, compaction, LLM vs code-driven workflows, etc)

lethain.com/agents-series/

02.01.2026 01:20 👍 16 🔁 2 💬 1 📌 1

Great site! It’s pretty cool how approachable projects like this are getting

28.12.2025 23:14 👍 1 🔁 0 💬 0 📌 0

Thank you! 🙏

26.10.2025 14:20 👍 2 🔁 0 💬 0 📌 0

There's also a sense, for me anyway, that the frontier has moved somewhere else -- I'm not quite sure where -- but a lot of social media today feels like a regurgitation of things that already happened rather than something new/interesting/evolutionary.

25.10.2025 22:24 👍 2 🔁 0 💬 0 📌 0

Yeah, absolutely an era I miss fondly. There was a post from @copyconstruct.bsky.social a week or two ago that captured the reality for me -- most of the folks I want to talk with are gone, and I've personally *mostly* left social media for all significant purposes.

25.10.2025 22:22 👍 1 🔁 0 💬 1 📌 0
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Crafting Engineering Strategy: How Thoughtful Decisions Solve Complex Problems Crafting Engineering Strategy: How Thoughtful Decisions Solve Complex Problems - Kindle edition by Larson, Will. Download it once and read it on your Kindle device, PC, phones or tablets. Use features like bookmarks, note taking and highlighting while reading Crafting Engineering Strategy: How Thoughtful Decisions Solve Complex Problems.

Digital edition of my fourth book, Crafting Engineering Strategy, is up for purchase! (Print copy should start shipping in next 2-3 weeks.) Tried to apply "Staff Engineer" formula to eng strategy topic, with a lot more editing 😂

www.amazon.com/Crafting-Eng...

25.10.2025 21:52 👍 15 🔁 2 💬 1 📌 1

*Good 😅

20.07.2025 04:49 👍 0 🔁 0 💬 0 📌 0

Could point! This probably does exist somehow already

20.07.2025 04:49 👍 1 🔁 0 💬 1 📌 0

Yeah, so you can imagine another stage in this process of summarizing all rfcs to extract problems, but I’m more specifically looking for a pattern we could scale across many functions, eg compliance feedback, security feedback, etc

20.07.2025 02:32 👍 1 🔁 0 💬 1 📌 0

Any good patterns for loading a Notion page as modifiable prompt to respond to other Notion pages and Slack messages? Eg as a simple example you could imagine I want to write architecture guidelines and then use that to comment on RFCs.

Is this just Zapier?

20.07.2025 01:50 👍 4 🔁 0 💬 1 📌 0

I love your post!

10.07.2025 02:20 👍 3 🔁 0 💬 1 📌 0
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Thoughts on Motivation and My 40-Year Career I’ve never published an essay quite like this. I’ve written about my life before, reams of stuff actually, because that’s how I process what I think, but never for public consumption. I’ve been pus…

New post up, with a bunch of thoughts on what drives me personally, and my own 40-year career (h/t @lethain.com).

I have a pretty unusual life story. But one of the reasons I love the tech industry so much is how common unusual stories like mine have historically been.

charity.wtf/2025/07/09/t...

09.07.2025 21:31 👍 155 🔁 33 💬 15 📌 18
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Will Larson — Executive Runtime Podcast I'm thrilled to welcome Will Larson, Chief Technology Officer at Carta and a thought leader whose work has shaped how many of us think about engineering leadership. Will is the author of three influen...

Did my first podcast in some time as I start ramping up a bit around getting started as new CTO at Imprint and also getting close to releasing next book!

Podcast up at www.executiveruntime.show/episodes/04-...

16.06.2025 22:19 👍 7 🔁 0 💬 1 📌 0

I think programming languages are already pretty exhaustively represented in the training sets, although it certainly varies language by language, and providing more detailed in-context learning is usually preferable in my experience.

14.06.2025 17:35 👍 1 🔁 0 💬 1 📌 0
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AI Companion / Generating Systems Models Crafting Engineering Strategy has a chapter on systems modeling along with a number of examples. Those examples focus on using the lethain/systems python library to generate models using a Jupyter not...

Have six (draft, unedited) chapters of my upcoming book exploring this idea in a bit more detail!

craftingengstrategy.com/aic/generate...

14.06.2025 17:18 👍 0 🔁 0 💬 0 📌 0
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What is the competitive advantage of authors in the age of LLMs? Over the past 19 months, I’ve written Crafting Engineering Strategy, a book on creating engineering strategy. I’ve also been working increasingly with large language models at work. Unsurprisingly, th...

Full piece at lethain.com/competitive-... going into the concept a bit more deeply.

14.06.2025 17:18 👍 1 🔁 0 💬 1 📌 0
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Over the last year, as I've spent more time working with LLMs to power product features, I've also been thinking about how LLMs impact me as a long-form author. Of the ideas I've had, I'm particularly interested in the idea of building, and selling, books as "datapacks" for LLMs.

14.06.2025 17:18 👍 14 🔁 1 💬 2 📌 1

Part of this project that I'm excited about is also releasing an LLM-optimized version of the book designed to be throw into an Claude/ChatGPT project as in-context learning, which I'm working with O'Reilly to distribute. Not available yet, but you ca see use examples on website!

12.06.2025 04:28 👍 5 🔁 0 💬 0 📌 0
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Crafting Engineering Strategy

You can already read the full, unedited version of the book online at craftingengstrategy.com (most of those have also come out on my blog over the past 18 months as I wrote)

12.06.2025 04:28 👍 9 🔁 3 💬 1 📌 0

Still only part way through the editing process, but excited to announce Crafting Engineering Strategy, my upcoming book with O'Reilly on engineering strategy coming later this year (sometime Q4).

12.06.2025 04:28 👍 26 🔁 1 💬 1 📌 0
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My desk setup in 2025. Since 2020, I’ve been working on my desk setup, and I think I finally have it mostly pulled together at this point. I don’t really think my desk setup is very novel, and I’m sure there are better ways...

My bi-decade update on my desk setup 😂 Finally found a dock that lets me swap from windows desktop with dedicated GPU to OSX laptop with a single thunderbolt cable!

lethain.com/desk-setup-2...

07.06.2025 16:44 👍 19 🔁 1 💬 0 📌 0

This is a fascinating thread. And it has lots of my favorite thing: details.

I could give a shit about people who pounce online, flaming on and on about how wrong I am.

I love it when people reply with details about their very different experience.

The details give it heft. I can learn from them.

02.06.2025 16:33 👍 26 🔁 1 💬 0 📌 0

Coordination between company facilities teams and building’s janitor teams on how to clean rooms

23.05.2025 12:47 👍 1 🔁 0 💬 0 📌 0

Hah, I've heard of a few companies that did something similar! I don't think the _intent_ is wrong, but I do think it might be a lot more direct to educate the folks not sharing the space effectively.

22.05.2025 23:42 👍 1 🔁 0 💬 0 📌 0

Looking for startup to angel invest in that solves problem of chairs being routinely positioned to block video cameras in office meeting rooms.

(I've tried petitioning to remove chairs from rooms, but this innovation has met substantial resistance, so we need to innovate here.)

22.05.2025 23:27 👍 3 🔁 0 💬 2 📌 0

I respect you for that, but cannot join you lol

22.05.2025 01:36 👍 1 🔁 0 💬 0 📌 0

Each time I open LinkedIn I pray I don’t somehow accidentally click on the brain teaser game and become shamed forever off the internet

21.05.2025 14:51 👍 11 🔁 0 💬 1 📌 0
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This time experimenting with MCP server for generating and running systems models ( github.com/lethain/syst... ). I think it's pretty wild how well this works, especially the tool to inject domain-specific language usage documentation into the context window.

10.05.2025 22:43 👍 10 🔁 1 💬 0 📌 0

Yeah… this is what I believe but if you told me I was wrong I wouldn’t argue too much 😂

05.05.2025 16:44 👍 1 🔁 0 💬 0 📌 0