In this episode of the Lex Fridman Podcast, the team behind Cursor shares their vision for AI-powered programming. They discuss how Cursor aims to create a harmonious hybrid of human and AI capabilities, allowing programmers to effortlessly navigate complex systems. The podcast explores Cursor's key technical features, such as predicting and applying code edits and a visual diff interface.
The team also shares insights into AI's transformative impact on programming workflows. They believe AI will serve as a powerful assistant, handling tedious tasks so programmers can focus on high-level design and rapid iteration. However, the integration of AI into programming environments presents challenges, including scaling, infrastructure, security, and privacy concerns, which the team is actively tackling.
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Cursor emerged in response to the rapid advancements in AI, particularly large language models (LLMs). The team observed that while tools like GitHub Copilot were groundbreaking, they only scratched the surface of AI's potential to transform programming workflows.
Cursor aims to cultivate the "engineer of the future" - a sophisticated hybrid of human and AI capabilities. According to the team, being ahead in AI-powered programming by even a few months translates to exceptional productivity gains. Their goal is for programmers to effortlessly navigate complex systems by harmonizing human ingenuity with AI's capabilities, outperforming even pure AI systems.
Cursor's "Tab" feature uses custom AI models to predict and apply entire code edits, going beyond basic autocomplete. The team aims to eliminate repetitive coding tasks, allowing programmers to focus on high-level intent while the AI handles low-level details.
Sualeh Asif and Aman Sanger discuss how "Tab" extends to multi-line edits, file navigation, and terminal command suggestions, enabled by techniques like speculative edits and multi-query attention.
Cursor integrates a diff interface that visually highlights the AI's proposed code changes for easy review and acceptance. The team has experimented with UI approaches like side boxes and color-coding to streamline the review process.
Arvid Lunnemark notes the "verification problem" with large edits, and the exploration of solutions like highlighting important changes and providing model feedback via a shadow workspace.
The team believes AI will fundamentally transform programming by serving as a powerful assistant, not by replacing human programmers. AI is expected to handle tedious tasks so programmers can focus on both high and low-level aspects of their codebases.
Lunnemark suggests programming with AI may involve visual aids rather than just natural language. Sanger notes models that have seen code can pave the way for deeply integrated AI assistance.
While programmers will maintain control, their skills may evolve, with less emphasis on boilerplate code and more on high-level design and rapid iteration. Lunnemark envisions programmers quickly making major codebase changes with AI assistance.
A passion for coding and eagerness to experiment are seen as key traits for programmers in this future AI-integrated environment. However, programming will remain a highly valued and rewarding career.
Cursor faces scaling obstacles like efficiently storing and indexing large codebases, managing memory usage, and optimizing for low latency. The team has built custom solutions like Merkle trees and caching mechanisms.
Sanger also discusses hitting a data wall and considering scaling test time compute instead of model size.
Integrating language models, AI components, and real-time interactive features requires extensive engineering work, like building custom language servers and incorporating AI components without impacting performance.
Potential solutions like homomorphic encryption could enable privacy-preserving AI programming. However, centralization risks and the need to prevent model misuse raise security concerns that must be navigated carefully.
1-Page Summary
Cursor, an innovative code editor powered by artificial intelligence (AI), was born out of a vision to fundamentally transform programming as we know it.
The team behind Cursor identified the rapid advancements in AI, especially in large language models (LLMs), as a sign that programming would be fundamentally changed. They observed that current AI-powered tools like GitHub Copilot were only scratching the surface of what could be achieved in terms of improving programmer productivity and coding workflows. With their sights set on the future, they sought to develop a tool that deeply integrates AI capabilities in a way that couldn't be confined by the limitations of plugins or extensions in platforms like VS Code.
The Cursor team's ambition extends beyond creating another useful coding tool. Their vision for Cursor is to cultivate the "engineer of the future," a sophisticated hybrid of human and AI that outperforms a human programmer working alone. They imagine a workspace where programmers have ultimate control and can quickly iterate based on agile judgments to alter their codebases. This hybrid system will make programming feel effortless, with no wasted keystrokes, and the ability to navigate complex systems with ease. Cursor aims to empower programmers to harmonize their ingenuity with AI’s capabilities to not just match but outperform pure AI systems.
Cursor's founding team believes that AI's rate of innovation means that a few months of advancement can equate to years of efficiency gains. They maintain that being ahead in AI-powered programming, even by just a few months, translates to exceptionally enhanced productivity. This belief fuels their goal of continuous evolution, expecting that Cursor will render its current form obsolete within a year's time.
Michael Truell, a part of the Cursor team, likened the philosophy behind Cursor’s AI to that of a predictive autocomplete. He implied that the AI is engineered to predict and facilitate the next steps of the programmer, thus revolutionizing productivity. This suggests that Cursor’s AI aims t ...
The motivation and vision behind Cursor as a code editor powered by AI
The technical team behind Cursor delves into the groundbreaking features of their AI programming tool, designed to revolutionize the coding experience by predicting and applying entire code edits.
The team has introduced speculative editing with the Cursor "Tab" feature, aiming to predict and apply entire code edits. This involves custom models and techniques like speculative edits and multi-query attention to ensure the feature is fast and responsive. They aim to eliminate "low entropy" actions – predictable patterns or repetitive tasks in coding – to allow programmers to focus on the higher-level intent, leaving the AI to handle the tedious details.
Sualeh Asif and Aman Sanger discuss the "Tab" feature's capabilities, which extends beyond single-line edits to potential multi-line changes, jumping to different locations in the same file, and even suggesting terminal commands related to the code changes. The feature fast tracks the editing process by using speculative edits, allowing the model to generate tokens rapidly, even with larger batch sizes, thanks to the integration of multi-query attention. For low-latency execution, small models are employed, and sparse modeling using an MOE model has significantly improved performance with longer contexts.
Michael Truell emphasizes the goal of an ergonomic, smart, and fast editing experience, with the AI anticipating not just the next characters but entire coherent changes in the code. Aman Sanger adds that instruction fine-tuning and the creation of synthetic data for better responses also play a major role in Cursor's functionality. He also notes the importance of retrieval systems, re-ranking scores, and cache warming in making Cursor more intuitive and resource-friendly.
The Cursor team has experimented with various UI approaches to streamline the diff review process. The diff feature highlights the changes in proposed code, with different iterations focusing on intuitive and efficient review. A side box displays the codes to be deleted and added, while previous versions used color-coding to represent deletions and suggestions subtly.
Arvid Lunnemark addresses "the verification problem," ...
The technical implementation details of Cursor's key features
As AI continues to evolve, the team discusses its expected transformative impact on programming, not by replacing human programmers but by amplifying their productivity and creativity.
AI in programming is seen as a powerful assistant to the programmer. The idea is not to fully automate programming but to keep the human programmer in the driver's seat. AI is expected to handle tedious details, allowing programmers to focus on both high-level and low-level aspects of their codebase fluidly. The team expresses frustration that while models improve, the coding experience hasn’t changed much. They see AI-powered tools enabling new capabilities and experiences for programmers, enhancing productivity and the ability to use new features quickly.
Arvid Lunnemark points out that programming with AI’s help won’t always involve natural language. In some cases, showing an example or using visual elements might be more efficient. The foundational knowledge of code built up by AI during pre-training means it could prove useful for recognizing bugs or sketchiness in code.
Aman Sanger discusses models in pre-training that have seen code and can answer questions about it, paving the way for a programming future where AI’s assistance is vastly integrated. Michael Truell echoes this sentiment, foretelling that the best AI-driven products in the coming years will greatly surpass today’s standards. He suggests that AI has already made programming more enjoyable by reducing boilerplate and allowing faster, more controlled building.
Programming is set to become a strategic partnership between human direction and AI execution. The concept "pre-empt" assists in querying AI, considering the limited context space and external codebase information. Lunnemark says programmers should do what comes most naturally to them, with the system figuring out how to make their input make sense. Truell emphasizes that while AI can have a conversation about software building, humans should maintain control over the numerous micro-decisions involved in software design.
The team suggests that programmers might be able to edit pseudocode and see corresponding actual code changes, keeping them in control while gaining productivity. Lunnemark even posits that formal verification could take over testing, with AI suggesting specs for functions and computing proofs for implementation.
Arvid Lunnemark envisions programmers quickly making significant codebase chang ...
The role of AI in the future of programming and coding workflows
As AI-powered programming tools gain popularity, teams like Cursor's face complex technical and infrastructure obstacles. These challenges include efficiently handling large codebases and growing user numbers, maintaining performance, and ensuring privacy.
Caching, database overflows, and table scaling issues are some of the technical hurdles discussed by Michael Truell. To manage semantic indexing of codebases and answer related questions, Cursor built custom retrieval systems that are challenging to scale. Sualeh Asif underscores the difficulty of scaling the tool for companies with large, legacy codebases. Aman Sanger indicates hitting a data wall and considers improving models' performance by scaling test time compute instead of model size.
To tackle problems related to scalability, the team utilizes a Merkle tree structure. Sanger also mentions caching the actual vectors computed from the hash of given code chunks, which accelerates processing for additional users. Sualeh Asif mentions ongoing experiments to improve file suggestion accuracy. To enhance efficiency and reduce overhead, the team employs a KVCache for storing keys and values from the transformers' attention mechanism.
The integration of language models, AI components, and real-time interactive features necessitates considerable engineering work. Lunnemark discusses the use of language server protocol communication in Cursor, which interfaces with various language extensions vital for feedback to AI models. Running this protocol in the background requires nuanced engineering to ensure user experience is not negatively impacted.
Challenges include incorporating AI components like automatic context, which could potentially slow down models and make them expensive. Cursor faces the challenge of handling large AI models that demand significant computational resources. Sanger talks about scaling issues with models of experts (MOEs), which could be prohibitive in size for local use on users' machines.
Privacy concerns are paramount with AI mo ...
Challenges around scaling and infrastructure when building an AI-powered programming tool
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