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Andrej Karpathy on why we still need humans in the loop
Y Combinator· 2025-06-24 21:46
I think guies are very useful for auditing systems and visual representations in general. And I think guies for example are extremely important to this because a guey utilizes your computer vision GPU in all of our head. Reading text is effortful and it's not fun.But looking at stuff is fun and it's it's just a kind of like a highway to your brain. We have to keep the AI on the leash. I think a lot of people are getting way over excited with AI agents and uh it's not useful to me to get a diff of 1,000 line ...
Powering the Future with Fusion
Y Combinator· 2025-06-09 21:26
Energy Demand & Sources - Energy demand in America is spiking for the first time in a decade, partly due to data centers powering the AI boom [1] - The increased energy demand is leading to the burning of more fossil fuels [1] - Fusion energy is presented as a clean, safe, and virtually limitless alternative energy source, mimicking the sun's energy production [1] Fusion Energy Development - Challenges remain in making fusion energy commercially viable and cost-effective [2] - Progress has been made in building machines that demonstrate the feasibility of fusion [2]
Fusion Energy Will Power the AI Boom
Y Combinator· 2025-06-06 14:00
These massive data centers are the beating heart of the AI boom that's reshaping our world and they're hungry for more electricity. That's one of the reasons that for the first time in a decade, demand for energy in America is spiking. To keep up, we're burning more and more fossil fuel and fast.But there's another path, a clean, safe, virtually limitless source of power. Fusion energy. Fusion is the way the sun works.Only here on Earth, we've actually struggled to be able to do it in a commercializable, co ...
Many AI apps today are like the horseless carriages of the late 19th century.
Y Combinator· 2025-06-04 17:24
You think that developers today are using AI in the previous generation of software development that they've been used to. Yes. Um, and so you you use this phrase, the AI horseless carriage.Maybe tell tell us what you mean by that. This is a reference to early automobile designs that looked a lot like carriages with the horse replaced with an engine, right. And there were all sorts of problems with that design.Yeah. And this phenomena we we see over and over and over again in technology like some some ones ...
Sometimes, the tech just needs time to catch up.
Y Combinator· 2025-06-02 16:59
Company Overview - Replicate 是一家在技术发展初期坚持下来的公司 [1] - 公司在疫情期间曾暂停运营数月,后重新启动并默默发展了两年 [2] - 图像扩散模型出现后,公司业务迅速爆发 [2] Business Development - Replicate 在默默无闻中构建产品两年,直到图像扩散模型出现才迎来爆发 [2]
State-Of-The-Art Prompting For AI Agents
Y Combinator· 2025-05-30 14:00
Prompt Engineering & Metaprompting - Metaprompting is emerging as a powerful tool, likened to coding in 1995 due to the evolving nature of the tools [1] - The best prompts often start by defining the role of the LLM, detailing the task, and outlining a step-by-step plan, often using markdown-style formatting [1] - Vertical AI agent companies are exploring how to balance flexibility for customer-specific logic with maintaining a general-purpose product, considering forking and merging prompts [1] - An emerging architecture involves defining a system prompt (company API), a developer prompt (customer-specific context), and a user prompt (end-user input) [1] - Worked examples are crucial for improving output quality, and automating the process of extracting and ingesting these examples from customer data is a valuable opportunity [2] - Prompt folding allows a prompt to dynamically generate better versions of itself by feeding it examples where it failed [2] - When LLMs lack sufficient information, it's important to provide them with an "escape hatch" to avoid hallucinations, either by allowing them to ask for more information or by providing debug info in the response [2] Evaluation & Model Personalities - Evals are considered the "crown jewels" for AI companies, essential for understanding why a prompt was written a certain way and for improving it [3] - Different LLMs exhibit distinct personalities; for example, Claude is considered more steerable, while Llama 4 requires more steering and prompting [5] - When using LLMs to generate numerical scores, providing rubrics is best practice, but models may interpret and apply these rubrics with varying degrees of rigidity and flexibility [5] Founder Role & Forward Deployed Engineer - Founders need to deeply understand their users and codify these insights into specific evals to ensure the software works for them [3] - Founders should act as "forward deployed engineers," directly engaging with users to understand their needs and rapidly iterate on the product [4] - The forward deployed engineer model, combined with AI, enables faster iteration and closing of significant deals with large enterprises [5]
In the AI era, the playbook is changing.
Y Combinator· 2025-05-28 17:55
Back in the pre-AI era, it was really hard to come up with good new startup ideas because the idea space had been picked over for like 20 years. And so a lot of the the startup advice that people would hear would be like you really need to like sell before you build. It was like the lean startup scale fast scale fast.But I would argue that in this new AI era that the right mental model is closer to what hard set which is just like use interesting technology, follow your own curiosity, figure out what's poss ...
How To Design Better AI Apps
Y Combinator· 2025-05-23 14:00
AI Development & Application - The industry is currently using outdated software development techniques for AI features, hindering the full potential of AI, which should enable users to program software using natural language [1][18] - AI application development is often approached by trying to fit AI into existing applications, rather than redesigning tools from the ground up to automate repetitive tasks [18][62] - The industry needs to move beyond the chatbot paradigm and focus on AI's capability to automate work and accomplish tasks on behalf of users [58][60] - A key element is providing users with "tools" that agents can use to accomplish tasks, such as labeling emails, archiving them, or writing drafts [53][54] System Prompts & User Control - Current AI applications often hide the "system prompt" (instructions given to the AI) from the user, limiting customization and personalization [1][11] - The industry should allow users to view and edit system prompts, enabling them to tailor the AI's behavior to their specific needs and preferences [8][10] - Allowing users to control system prompts shifts the responsibility for the AI's output from the developer to the user [35] - While not everyone may want to write system prompts from scratch, the option should be available, and AI could assist in generating and customizing prompts based on user history and feedback [41][42][48] Future of AI Development - The industry needs to develop better tooling and UI conventions for interacting with and teaching AI, potentially including AI-assisted system prompt writers [45][46] - AI models are good at processing instructions and turning them into text output, making them particularly effective for coding agents [31][32] - Founders should rethink existing tools from the ground up with AI, focusing on offloading repetitive work from users [61][62]
AI for Personal Finance
Y Combinator· 2025-05-20 15:54
Most humans are not rational about their finances. Questions like how much should I save for the future. Where should I invest my money to take the right risk for me.And how should I think about debt and taxes. How you answer these questions today will impact your freedom to do the things you want in the future. Until today, the way to answer these questions have been asking friends, Googling, sometimes hiring a financial adviser, or maybe even asking your bank.These options aren't great. They're filled wit ...
AI Voice Assistants for Email
Y Combinator· 2025-05-19 22:46
Voice Assistant Opportunity - The industry sees potential in voice-based email management, especially during commute times like a 20-minute drive, aiming for inbox zero upon arrival at work [1] - The industry recognizes the broader use cases of voice agents beyond driving, highlighting their current capabilities demonstrated by existing technologies [1] - The industry acknowledges the limitations of keyboard reliance, particularly for individuals with physical impairments, suggesting email as a prime area for voice assistant development [2] Email as a Central Hub - Email inboxes contain a wealth of personal information, including contacts, plans, and writing styles, making them ideal for building comprehensive personal assistants [2] Call to Action - The company is seeking teams to develop voice-based email processing solutions [1][2]