Justin McCarthy

founder former co-founder & CTO @StrongDM

[Justin McCarthy @BuiltByJustin]

"You are here"

That's how you read the dot in the logo.

We're getting to the steep part now, all of us.

It's better if we ride the curve together.

Come visit me and the team at our first center, Diffusion Silicon Valley. Diffusion Europe and Diffusion India coming soon.

https://t.co/KwE0FvWSzY

[dex @dexhorthy]

@cansar @mitchellh no better place to hack on the no more slop manifesto with @philipkiely @BuiltByJustin

[Justin McCarthy @BuiltByJustin]

see everyone Thursday at https://t.co/0BUQMrqNDz, thx @dexhorthy & @swyx for hosting

[swyx @aiDotEngineer CODE @swyx]

not kidding. scenes from the speaker rehearsal session last night. @lucasmeijer , @FabianHedin, @BuiltByJustin, and @kentcdodds made memorable splashes!!

follow @aiDotEngineer for live tweeting

[Justin McCarthy @BuiltByJustin]

@timClicks Let’s fill in pit mines. Before pouring concrete drill huge thermal loops for cooling. Park land on top.

[Justin McCarthy @BuiltByJustin]

We're called Diffusion because that's the mission - diffusing what's possible to every niche of the global economy. There is a geographic reality to this: conviction is contagious, it emanates from SF, and it propagates best F2F. Come visit.

[Gergely Orosz @GergelyOrosz]

I wouldn’t be surprised if 95%+ of devs spending $10K+ per month on AI, globally, were based in the Bay Area

Nearly everyone I talk here (devs, founders, CTOs etc) are AI-pilled in ways I rarely see outside. AI-pilled as in obsessed building more with agents, running agents when they sleep, designing loops to auto kick-off, running them during their commute. And talking with each other how and what they do and then taking those ideas and trying it

[Justin McCarthy @BuiltByJustin]

@patrickc suggest adding automatic screenshot functionality as well, so there's a visual reference for the agent as well. works well.

[Justin McCarthy @BuiltByJustin]

“Make now always the most precious time. Now will never come again.” https://t.co/if6d4b1vfD 😢

[Justin McCarthy @BuiltByJustin]

great chat with @sodio https://t.co/nlyiemSALj

[PWV @PWVentures]

Diffusion @BuiltByJustin on building a dark software factory.

See how people are actually working with AI at

@sodio @mojombo

#AI #DarkSoftwareFactory #AgenticEngineering

[Justin McCarthy @BuiltByJustin]

@thdxr your own in-house take on https://t.co/QxXoyUXsvu

[Justin McCarthy @BuiltByJustin]

@rjonesy @ranjanxroy some suggestions:
1. use generated images
2. html with strict word count limits
3. have adversarial "tldr agents" preprocess
4. use multi-agent consensus before anything is escalated to your attention, with feedback loop recording examples of improper escalations

[Justin McCarthy @BuiltByJustin]

just say no to walls of text

[Bruno Bornsztein @brunotorious]

Ruthlessly manage your context. Don't let agents flood you with garbage. Force them to hand you human-sized things to think about.

[Josh Elman @joshelman]

Talked to multiple founders yesterday who have been building their products over the last 3 years. Started manual code.

They feel behind and slower than companies that started this year with all code written by agents.

I have never seen such an order of magnitude difference.

[Justin McCarthy @BuiltByJustin]

A very concrete account of looping a signal (in this case, something undesirable) back to the production process. You can do the same for uptime, performance, costs, brand consistency, ongoing security, regulatory compliance and so on.

[Alan Wells @alanwells]

Just spent the last 7 days on the front lines of the vulnpocalypse fending off an active cyber attack on one of our products.

Some thoughts:

- Software factories are going to be required equipment for everyone. There’s just no way to keep up with the pace of highly automated adversaries without one.

- We were lucky because we had spent the last few months getting our software factory running well. It is nice to have for product development but proved to be absolutely essential this week.

- At the minimum you need to have a coding server in the cloud pre-provisioned with read only access to all your logs and all the services you depend on for observability. With that in place you are a prompt away from reasonably good situational awareness, ongoing monitoring with loops, and ability for coding agents to validate fixes against your actual, observed attack patterns.

- Shared coding server also unlocks multiplayer incident response where everyone can see every session and jump in as needed. Sharing session links that can be forked is much higher bandwidth than re-explaining things.

- You don’t need to be Ramp/Stripe/Uber scale to have a working software factory in the cloud. We are a team of 3. Ours is built with an @opencode server (thanks @thdxr!), a forked version of compound engineering optimized for automated workflows (thanks @kieranklaassen!) and a multiplayer agent in slack that handles crons (we have our own harness but pick your favorite here).

- To get our software factory up and running well, we had to stop all new product development for ~6 weeks and just focus on getting the validation systems working that enabled us to reliably shipping PR without human code review. This felt very painful in the moment but was totally worth the eventual speedup in velocity.

- KYC for @AnthropicAI & @OpenAI cyber programs is now easy and quick (at least for defensive access), but a day felt like a lifetime this week. Submit your app now before you really need it.

- Getting Mythos access unlocked a deeper level of analysis that helped us shift from reactive mitigation to proactive patching. Wish we had done this a few weeks earlier. Get started now!

[Justin McCarthy @BuiltByJustin]

@martin_casado from a talk last week!

[James Cham @jamescham]

Looking forward to this afternoon’s MIT AI panel on AI Maximalists with @annimaniac, @sschillace and @BuiltByJustin. Say hi if you’re here!

[Justin McCarthy @BuiltByJustin]

@ibuildthecloud don't forget the front matter

[Justin McCarthy @BuiltByJustin]

@martin_casado "soundscape" is up and running at the office now, 24/7 generative & capable of switching to Spotify playlists as required; optional DJ banter for light moods as well. Thx for the inspiration.

[Justin McCarthy @BuiltByJustin]

Well done @DanielleMorrill

[Danielle Morrill @DanielleMorrill]

my personal fast takeoff continues, finally have 24/7 code factory running for @groupthinkAI and doing a lot of fine tuning on costs but 📈 https://t.co/pPryLIRvle