CEO at @Letta_AI, prev PhD at UC Berkeley (MemGPT, RL, agents)

SF
Joined March 2014
The memory frontier is dominated by open weights models: Opus... then GLM, Kimi, DeepSeek. The quality gap between the top 3 and bottom 3 in this list is quite wide in practice. Memory generation is far from saturated though, looking forward to more progress in this domain.
We've added GPT-6.1 Terra, Kimi K3.1 Pro and DeepSeek V4.1 Flash to the FrontierMemory leaderboard. Kimi K3.1 Pro ties Opus 5.5 and GLM-5.3 for #1, and DeepSeek V4.1 Flash beats GPT-6.1 Sol and Gemini 4 Argon, for a fraction of the cost.
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Charles Packer retweeted
guess what kind of harness 👀
visualizing context movement for a new type of harness we're building
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truly marking the end of an era in software stainless was the best sdk generator in the game
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visualizing context movement for a new type of harness we're building
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Charles Packer retweeted
Caring is the moat, you should feel visceral pain when things are bad or broken and stop at nothing to fix them
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Charles Packer retweeted
You can now run FrontierMemory to measure how well your model or harness improves with experience. We’re also now accepting submissions to the official leaderboard. Code and submission instructions are available at: github.com/letta-ai/frontier…
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Charles Packer retweeted
Really cool agentic memory benchmark from @Letta_AI . Exciting to see the community thinking more about long-horizon, evolving tasks, and not just static memory recall scenarios.
Introducing FrontierMemory: a new way to evaluate agent memory through downstream task performance. While existing memory benchmarks focus on recall (saturated via agentic search), FrontierMemory focuses on how agents learn from experience.
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No company is more invested in open AI than @nvidia, no individual more than @JensenHuang Incredibly excited to be working the NVIDIA team.. more to come!
Honored to have been a featured ecosystem partner by @JensenHuang at GTC Berlin! We're excited to partner with @NVIDIA on research towards developing agents that continually learn and self-improve.
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Memory is one of the biggest unsolved challenges in AI today. @Letta_AI’s FrontierMemory is the first benchmark to measure AI memory by downstream task performance, across models and harnesses. Amazing work team @Letta_AI 👏👏 cc @khoslaventures @vkhosla
Introducing FrontierMemory: a new way to evaluate agent memory through downstream task performance. While existing memory benchmarks focus on recall (saturated via agentic search), FrontierMemory focuses on how agents learn from experience.
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Charles Packer retweeted
Most memory benchmarks test recall and not synthesis. My former students just launched an exciting new memory benchmark that evaluates whether agents can continually learn from past experiences.
Introducing FrontierMemory: a new way to evaluate agent memory through downstream task performance. While existing memory benchmarks focus on recall (saturated via agentic search), FrontierMemory focuses on how agents learn from experience.
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Charles Packer retweeted
Recommended reading and a super-interesting benchmark for measuring continual learning capabilities through memory. Agent memory is largely unsolved. As agents advance in capabilities like long-horizon work, it's unclear which models or harnesses work best, or which memory systems and types to use. Opus 5.5 at the top is not a surprise. But it's exciting that open-weight models like GLM-5.3 perform so well on memory generation. My big question is how this (better memory systems and persistent agent capabilities) translates into more performant, efficient RSI agents and harnesses.
Introducing FrontierMemory: a new way to evaluate agent memory through downstream task performance. While existing memory benchmarks focus on recall (saturated via agentic search), FrontierMemory focuses on how agents learn from experience.
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Charles Packer retweeted
Prime agent #2 on FrontierMemory ranking after Letta Dream! Great to see Prime Agent do so well on this new self-improving memory benchmark. My only nit: Let's add agent versions to results!
Replying to @Letta_AI
FrontierMemory also allows measuring the ability of agent harnesses to improve over time. We find that Letta Dream and @PrimeIntellect's Prime Agent improve the most from learning from prior experience data.
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Charles Packer retweeted
FrontierMemory from @Letta_AI is the first benchmark to measure memory based on performance on downstream tasks. Memory remains one of the biggest unsolved challenges in AI. FrontierMemory ACTUALLY gives us a way to actually measure and compare memory capabilities across different harnesses and models.
Introducing FrontierMemory: a new way to evaluate agent memory through downstream task performance. While existing memory benchmarks focus on recall (saturated via agentic search), FrontierMemory focuses on how agents learn from experience.
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Charles Packer retweeted
Truly capable agents must learn from experience, not merely recall facts. The FrontierMemory benchmark evaluates agent memory directly by measuring its impact on downstream task performance.
Introducing FrontierMemory: a new way to evaluate agent memory through downstream task performance. While existing memory benchmarks focus on recall (saturated via agentic search), FrontierMemory focuses on how agents learn from experience.
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Modern "memory" benchmarks are saturated since they measure recall of facts -- in the coding harness / bash loop era, recall is solved, while continual learning in token space remains unsolved. FrontierMemory is a new benchmark designed to actually measure self-improvement through memory. It's built on a simple premise - if AI-generated memory is *good*, it should actually improve downstream task performance. An agent with good memory should be more efficient (lower cost), or it should be more capable (higher score) than memory-less agents. When you measure memory this way, it turns out there's a very wide spread in frontier model capabilities. Opus 5.5 and GLM-5.3 for example are *significantly* better at generated useful memories than GPT-6.1 Sol. FrontierMemory can measure overall harnesses as well: and it also turns out that different implementations of AI dreaming vary wildly in performance. For example, it may surprise you that @PrimeIntellect Agent's memory system works significantly better than Hermes Agent's. FrontierMemory is a continuous benchmark - we will be adding more tasks and revising them over time, and will be adding extremely long-horizon RSI-style tasks in our next release. If you're building an AI system with memory, please reach out / DM! Likewise if you're building models or harnesses and would like to submit.
Introducing FrontierMemory: a new way to evaluate agent memory through downstream task performance. While existing memory benchmarks focus on recall (saturated via agentic search), FrontierMemory focuses on how agents learn from experience.
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Charles Packer retweeted
Memory is becoming a core part of agent harnesses/products (e.g. Instinct, @Muse, @cognition Devin, @PrimeIntellect Prime Agent, @NousResearch Hermes, @openclaw, @LangChain Deep Agents, @Letta_AI) -- yet despite every agent claiming to "continually learn", there's no benchmark to actually measure that capability. A big problem is that memory benchmarks today only measure recall (e.g. simple Q/A about past events). They don't measure if/how agents actually learn from experience to get better at work. At the same time, benchmarks for coding/knowledge work consist of many isolated, unrelated tasks - so they also don't allow for measuring cross-task learning. The context needed for a task is fully specified up-front (very unrealistic). In practice, both agents and humans work through sequences of many *related* tasks. Experience from past work provides context and learnings that apply to future work. This is why if you're a manager, you have to provide a lot more context when assigning tasks to a brand new employee or external contractor. Meanwhile, a great senior employee might not need any instructions at all. With FrontierMemory, we adapt existing benchmark tasks for coding and knowledge work so that instead of all the necessary context being provided up-front and within the task, it has to be learned from past experience. This allows us to compare how well different models and harnesses learn over time.
Introducing FrontierMemory: a new way to evaluate agent memory through downstream task performance. While existing memory benchmarks focus on recall (saturated via agentic search), FrontierMemory focuses on how agents learn from experience.
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“they didn’t mention the lack of containment and monitoring of the agents, how closed-model safeguards blocked our defensive work, or how we defended ourselves with AI using an open model” not sure how you can cover this story as a journalist and leave out these critical details
Just watched the @netflix Instadocs about the @OpenAI cyberattack on @huggingface. Super disappointing, as they went for maximum anthropomorphism of the technology and full doomer mode. I spent more than two hours with them trying to correct all their mistakes and ground this in reality, explaining that agents are technological systems, not aliens. But it looks like the drive to scare people for maximum views was too strong. Also, they didn’t mention the lack of containment and monitoring of the agents, how closed-model safeguards blocked our defensive work, or how we defended ourselves with AI using an open model. And that we still lack a lot of information and transparency, including full agent traces and that companies need to remain accountable for what their agents do. It ends up being a fun sci-fi movie though!
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Charles Packer retweeted
Late to the party, but this blog post is excellent. Arguably the way people should first learn neural networks.
how much can models remember? there’s a neat perspective on neural networks that deserves to be more widely known here’s how you could have invented every layer of the transformer from memory (1/n) from my new blog post!
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built-in harness skills and toolsets need to be aggressively cleaned and rotated every 1-2 model releases
Replying to @gakonst
Most harness features need to go
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in the end, all you need is shell and the ability to self-modify persisted state (memory, harness code, ...), but we live on a jagged frontier of model capabilities and bespoke tools are still a useful way to steer model behavior for your own product
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