Corey (CJ) Gwin (@corey_gwin) header
Corey (CJ) Gwin (@corey_gwin) profile picture

product dude. decade in startups. solutions to the right problems. product at https://teapaw.org/t.co/ltNOc6NdTV + https://teapaw.org/t.co/0NEfAW8E4J. this is my notepad.

Joined May 2008
Photo by Corey (CJ) Gwin (@corey_gwin)Photo by Corey (CJ) Gwin (@corey_gwin)Photo by Corey (CJ) Gwin (@corey_gwin)Photo by Corey (CJ) Gwin (@corey_gwin)Photo by Corey (CJ) Gwin (@corey_gwin)
All at once.
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Corey (CJ) Gwin retweeted
the most import skill in 2026 is still being able to tell your agents "wtf is this crap, no, not like this" if you stop doing that, you're basically fucked, despite what some devfluencers would like you to think.
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Corey (CJ) Gwin retweeted
This is actually INSANE. Fable 5.2 just created this in one shot, and I did it live on stream. I gave Claude one prompt. It wrote code that builds the entire room in Blender: the desk, the MacBook, the light, even Clawd. The laptop screen is a web page Claude built to look like the Claude app, played on the laptop inside the 3D scene. Then it animated everything itself: 13 camera shots, every single key press, Clawd jumping around, and the sun going from golden hour to night to sunrise. It rented 10 GPUs on RunPod and rendered the whole thing in 4K in 52 minutes. Total cost: $5.75. It graded it, added the titles, and made the music and sound effects with ElevenLabs. (More info below)
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Corey (CJ) Gwin retweeted
As you become an adult, you realize that things around you weren't just always there; people made them happen. But only recently have I started to internalize how much tenacity *everything* requires. That hotel, that park, that railway. The world is a museum of passion projects.
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Corey (CJ) Gwin retweeted
The “IKEA Effect” is about to make a lot of vibe coders really sad. iykyk
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Corey (CJ) Gwin retweeted
my vocal synth models the vocal tract as a network of branching acoustic tubes, unlike vocaloid which stitches together and pitch-shifts phoneme recordings. still working on improving naturalness by tuning it against recordings of real singers, but I'm already impressed at how cool it sounds!
I only make serious software
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Corey (CJ) Gwin retweeted
CANCEL your weekend plans. The 2027 meta just dropped. You NEED to: • Build a computer-use agent that parses the DOM, diffs screenshots and maps clicks to coordinates so it can drive legacy software with zero APIs • Ship generative UI where your LLM returns live React components instead of markdown blobs and watch your product feel 10 years newer • Wire a System-One router that resolves 95% of requests in milliseconds for fractions of a cent, escalating only the hard 5% to reasoning models • Kill your `while True` loop and rebuild it as a Temporal state machine that resumes from the exact node after a crash or a 3-day approval • Write a raw MCP server in pure JSON-RPC so any external agent can call your product with scoped credentials, no SDK required • Add grammar-constrained decoding so your agent emits 100% valid JSON on the first try, every try, forever • Build a trajectory grader in CI that blocks the merge the second a tool-call sequence deviates from the golden path • Ship an inter-agent sanitization proxy that executes prompt injections before they cross a single agent boundary • Wire a PII unmasking proxy that swaps sensitive data for UUIDs before inference and restores it after with full audit logs • Add a cost kill-switch that halts any loop projected to exceed $0.50 and degrades frontier → mid-tier → local → cache • Implement KV-cache prefix sharing at the gateway and cut Time-To-First-Token by 80% on repeated system prompts • Set up speculative decoding: local 3B drafts, frontier 70B verifies, acceptance rate logged on every single request • Shadow-route 5% of production traffic to your new model, diff trajectories and cost silently, auto-post the report to Slack • Automate the DPO flywheel: thumbs-down → preference pairs → nightly LoRA → eval-verified promotion, zero human touch • Build a voice loop with VAD and sub-1s interruption handling, streaming tokens and tool calls simultaneously • Ship an API-to-browser fallback that spawns a headless browser the moment a REST endpoint 404s, finishing the job anyway • Add a WebGPU shim so a 2B model runs in the browser when the cloud dies and your users never see a spinner • Fuzz your own agent swarm with malformed tool outputs and context overflow until it self-heals without a single pager alert • Publish one benchmark: your system vs the naive baseline, on cost, latency and task success, fully reproducible The wrapper era is over. The systems era pays. You have way too much to do. Bookmark & Repost.
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Corey (CJ) Gwin retweeted
agents are going to cause a breakdown of human behavior assumptions underlying today's systems. i've started thinking about it as friction collapse. without friction, a number of norms will collapse. consider selling tickets to a concert/event. today, you can post them at a certain time and it's first come first serve. soon everyone's agent will persistently monitor, and as soon as they are posted for sale, thousands of people will instantaneously be trying to buy the same ticket. how do you even resolve this? sell the ticket to the person whose agent gets there fractions of a second before? we're seeing the same thing with job applications, restaurant reservations, but basically anything that relies on participation requiring effort is going to break down. sales emails/calls, participation in government benefits, apartment rentals, doctors appointments, RFP responses. customer support won't be able to handle the user who will not drop their point of dissatisfaction. with no friction, these systems just don't work anymore. business models will break down: - flights/hotels will be consistently cancelled and rebooked at the lowest price (great use case for your agent if you don't have this already set up) - subscriptions will be cancelled - retailers won't be able to arbitrage price differences as the agent will find the cheapest place to buy anything - insurance denials (health/auto/home/etc.) will be fought tooth and nail - bank interest rates will be optimized and avoidable charges will be avoided a lot of what we perceive as stable social coordination is actually an equilibrium sustained by human inefficiency. rationing is a product of human slowness. signaling effort/interest/intent is a key part of our social infrastructure. inertia is a key to many business models. information asymmetry is everywhere. and attention is monetized thoroughly. with agents, none of these things are true. humans will simply demand what they want and have their agents get it for them. there is going to be a fundamental renegotiation of how markets allocate resources, how people signal intent, and how businesses capture value.
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my spidey senses are telling me the labs are, as we speak, using unguardrailed versions of their unreleased models to systematically reverse-engineer ALL of the internet’s software, apps, and games, then feeding the reconstructed source code straight into their training pipelines while simultaneously building guardrails to ladder-pull the rest of us
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You know someone is good at Product when they also have uniquely good taste in a wide variety of other products.
The holidays are fast approaching, so I’m back with my sixth (!!) annual gift guide. It's got over 100 gift ideas—all things I actually use, love, and recommend. This started out as a random post idea, but now you’d be surprised how many people ping me asking when the new list will be out. As always, the collection includes a mix of practical stuff with a lot of fun and delight, from high-end products to very affordable items. There are no affiliate links here, and I’m not benefiting from recommending any of these products. Pro tip: After reading it, point your favorite AI agent at the post and have it brainstorm gifts for your family, friends, and coworkers. Here's the guide: lennysnewsletter.com/p/lenny…
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Gift guides are probably a good exercise for all Product peeps.
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Indicates you understand others, novelty and utility.
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Corey (CJ) Gwin retweeted
this is basically the bitter lesson at work the smartest models will need fewer and fewer tokens, they won't need to verify their work or check it for bugs, they will just be right
maybe a hot take but i now consider adversarial reviews mostly a waste of tokens. far better to use those tokens on empirical combined with formal verification. i have updated pstack to use the interrogate skill less, and eventually i think i may remove it altogether i have found very little value with code review in the abstract, agents tend to just get lost in the nitpicks and yagnis
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Corey (CJ) Gwin retweeted
I've started asking ChatGPT to write the most unhinged replies to every AI-generated cold email I get, and honestly, it's low-key my favorite part of the day. I don't edit them. I just send as is every time.
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Corey (CJ) Gwin retweeted
this guy figured out how to leak your exact location from any video with sound using the Doppler curves of nearby airplanes
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Corey (CJ) Gwin retweeted
I asked Claude: "What types of businesses outside of the labs will get stronger as raw intelligence explodes?" Honestly, spot on response.
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don't just regurgitate what i said. don't overweight this turn. think hard, challenge if necessary, and research as need.
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Corey (CJ) Gwin retweeted
every product i use should just be a headless mcp, that feeds into an agent, where i never have to think about anything underneath. except for our product, of course. in our product, customers love the ui and love us very much. we're special that way.
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A good harness converges on a good project management system
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