Active Graph Agent Runtime (BabyAGI 4) — Yohei Nakajima, Untapped Capital @aiDotEngineer
Active Graph Agent Runtime (BabyAGI 4) — Yohei Nakajima, Untapped Capital  @aiDotEngineer
Uploaded July 2026 | Updated September 2026, 3 weeks ago
Yohei Nakajima was running a 500 question eval when his API key died at question 350. Normally that means restarting the whole long agent from scratch. Instead it rolled back one step and resumed at 353, because in ActiveGraph the log is the agent. Most people build agents around the LLM and bolt on memory and logging; Nakajima, the creator of BabyAGI, flips it and builds around an immutable event log. Every action and every change to the agent flattens into one typed log, which projects a graph that is the agent's state, so you get replays, rollbacks, and forks for free.

On top of the log sit behaviors that react to graph changes and emit events, policies that decide what the agent may change on its own versus what needs a human or a contradiction check, and swappable packs for memory, tools, and chat. The LLMs never talk to each other; they only touch shared state, an idea he borrows from 1970s blackboard systems and Kafka, and his hunch is that AI writes this style better than modern agent code because it has decades of training data on it. The payoff is self improvement: a loop that forks the agent, proposes a patch, gates it behind sandbox tests, and keeps it only if accuracy actually rises, and a lab that reads his blog posts, runs its own experiments, and once found a bug in its own code and opened the PR.

Speaker info:
- github.com/yoheinakajima/activegraph
- https://x.com/yoheinakajima
- linkedin.com/in/yoheinakajima

Timestamps:
0:00 - ActiveGraph and three years of BabyAGI
1:55 - Build around the log, not the LLM
3:24 - Behaviors, policies, and views
6:43 - Packs and the blackboard architecture lineage
8:12 - The log as memory, and the API key that resumed itself
9:53 - Reference agents built natively on the log
11:11 - Self improvement: regimes and controlled self modification
12:25 - ActiveGraph Lab writes its own experiments
13:02 - A Pokemon card competition as a testbed
14:33 - Surprises: why AI architects this better
15:49 - Why an agent needs an experiential world model
Active Graph Agent Runtime (BabyAGI 4) — Yohei Nakajima, Untapped CapitalMorgan Stanleys ALPHALAB: Multi-Agent Research Across Optimization Domains — Brendan RappazzoAI tools for Forward Deployed Engineering — Vasuman Moza, Varick AgentsEnding AI Slop — Thais Castello Branco, Taste LabsYour Code Has Bugs. Lean4 Has Proofs: Formal Verification for Engineers — Varun Pant, AWSBuild the AI GTM Agent That Knows the Buyer - Dr. Sajjan Kanukolanu, Position2 (Position Squared)Serving 2 Million Models Without Melting: Scaling the Hugging Face Hub — Arek Borucki, Hugging FaceDont Let the LLM Drive - Ornella Bahidika & Joel Allou, MicrosoftHow to avoid disaster when vibe-coding a billing engine — Andrew Garvin, StripeEinstein Arena: Harnessing Collective Agent Intelligence for Open Science — James Zou, Together AIVideo Has No Memory. Heres How We Built One. — James Le, TwelveLabsAnthropic Workshop: Build Agents That Run for Hours — Ash Prabaker & Andrew Wilson
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Active Graph Agent Runtime (BabyAGI 4) — Yohei Nakajima, Untapped Capital

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