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Charles Packer
Letta
1,538 posts
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Charles Packer
Letta
@charlespacker
CEO at @Letta_AI, prev PhD at UC Berkeley (MemGPT, RL, agents)
SF
charlespacker.com
Joined March 2014
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  • Pinned
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    Charles Packer
    Letta
    @charlespacker
    Dec 11, 2025
    Continual learning in token space:
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    Continual Learning in Token Space
    From letta.com
    46K
  • user avatar
    Charles Packer
    Letta
    @charlespacker
    Jan 9, 2025
    guys agent frameworks are so stupid, all you need is an anthropic API key and a while loop …and a FastAPI server so that we can use the agents programmatically …and some good API designs to enable multi user and multi agent support …and a tool execution sandbox so that the
    128K
  • user avatar
    Charles Packer
    Letta
    @charlespacker
    Nov 14, 2024
    the new frontier: AI agent hosting/serving 👾🛸 the AI/LLM agents stack is a significant departure from the standard LLM stack. the key difference between the two lies in managing state: LLM serving platforms are generally stateless, whereas agent serving platforms need to be
    The AI agents stack in late 2024, organized into three key layers: agent hosting/serving, agent frameworks, and LLM models & storage.
    65K
  • user avatar
    Charles Packer
    Letta
    @charlespacker
    Oct 16, 2023
    Introducing MemGPT 📚🦙 a method for extending LLM context windows. Inspired by OS mem management, it provides an infinite virtualized context for fixed-context LLMs. Enables perpetual chatbots & large doc QA. 🧵1/n Paper: arxiv.org/abs/2310.08560 GitHub: github.com/cpacker/memgpt
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    94K
  • user avatar
    Charles Packer
    Letta
    @charlespacker
    Oct 30, 2025
    Today we're releasing Context-Bench, a benchmark (and live leaderboard!) measuring LLMs on Agentic Context Engineering. C-Bench measures an agent's ability to manipulate its own context window, a necessary skill for AI agents that can self-improve and continually learn.
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    30K
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    Charles Packer
    Letta
    @charlespacker
    Aug 27, 2025
    Prior to GPT-5, Sonnet & Opus were the undisputed kings of AI coding. It turns out the GPT-5 is significantly better than Sonnet in one key way: the ability to recover from mistakes. Today we're excited to release our latest research at @Letta_AI on Recovery-Bench, a new
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    38K
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    Charles Packer
    Letta
    @charlespacker
    Dec 31, 2024
    Really great reading list from @swyx - amazing to see MemGPT in the top 5 agent papers, side-by-side with one of my favorite LLM papers: ReAct IMO ReAct (@ShunyuYao12 et al) is *the* most influential paper in the current wave of real-world LLM agents (LLMs being presented
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    Latent.Space
    @latentspacepod
    Dec 27, 2024
    🆕 Presenting: The 2025 AI Engineering Reading List latent.space/p/2025-papers 1 paper/blog/model family per week for every week of 2025, for you to run paper clubs or binge over the break.
    40K
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    Charles Packer
    Letta
    @charlespacker
    Sep 23, 2024
    Excited to finally announce @Letta_AI ! The next frontier in AI is in the stateful layer above the base models - the "memory layer", or "LLM OS". Letta's mission is to build this layer in the open (say "no" 🙅 to privatized chain of thought).
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    31K
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    Charles Packer
    Letta
    @charlespacker
    Oct 21, 2025
    wild.. first we got self-improving @Letta_AI agents inside teddy bears and now they're running on Unitree quadropeds?
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    Animus
    @animusuno
    Oct 21, 2025
    🦋 Last week, our team took delivery of a new quadruped robotic dog from @UnitreeRobotics — the Unitree Go 2 AIR. With @Letta_AI and the Animus framework, developers can build embodied agents that think, learn, and act in the real world. Watch how we plan to bring Animus to
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    Charles Packer
    Letta
    @charlespacker
    Apr 21, 2025
    💤 sleep-time compute: make your machines think while they sleep -> arxiv.org/abs/2504.13171 over the past several months we (at @Letta_AI) have been exploring how effectively utilize "sleep time" to scale compute. the concept of "sleep-time compute" is deeply tied to memory -
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    Letta
    @Letta_AI
    Apr 21, 2025
    We're excited to release our latest paper, “Sleep-time Compute: Beyond Inference Scaling at Test-Time”, a collaboration with @sea_snell from UC Berkeley and @Letta_AI advisors / UC Berkeley faculty Ion Stoica and @profjoeyg letta.com/blog/sleep-tim…
    20K
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    Charles Packer
    Letta
    @charlespacker
    Oct 28, 2025
    the terrible responses api rollout is a perfect example of how to lose first mover advantage
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    Sarah Wooders
    Letta
    @sarahwooders
    Oct 28, 2025
    Pretty crazy to see Anthropic API being implemented over ChatCompletions, which used to be the standard (until OpenAI refused to properly support reasoning)
    15K
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    Charles Packer
    Letta
    @charlespacker
    May 18, 2024
    phd complete, time to go merge some PRs
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    8.5K
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    Charles Packer
    Letta
    @charlespacker
    Jun 29, 2025
    Welcome to Claude Code
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    8.5K
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    Charles Packer
    Letta
    @charlespacker
    Sep 10, 2025
    awesome to see another example of sleep-time compute deployed in production, especially on such a slick consumer app "setting up the memory can take up to 6 hours" congrats on the launch @intelligenceco 👏 letta.com/blog/sleep-tim…
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    General Intelligence Company
    @intelligenceco
    Sep 9, 2025
    Replying to @intelligenceco
    Cofounder is actually two agents - a memory agent which works in the background structuring a knowledge graph, and a real-time agent which accesses our memory. This allows us to take advantage of sleep-time-compute to better handle episodic memory and business ontology. In
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