/Tech21d ago

Yohei Nakajima releases Active Graph, an open-source event-sourced reactive graph runtime for long-running auditable agentic systems that replaces the loop architecture of his 2023 BabyAGI

State changes are recorded in an immutable queryable event log.

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Yohei@yoheinakajima

i'm excited to open source Active Graph: an event-sourced reactive graph runtime for long-running, agents 🔄🧠

events/logs projects a graph. reactive behaviors react and affect the graph. fork-and-diff agent runs. no A2A, no workflows, no DAG

site: http://activegraph.ai docs: http://docs.activegraph.ai github: https://github.com/yoheinakajima/activegraph quick start: pip install activegraph

this is an early experiment in a new paradigm for agent architecture 🧪

7:00 AM · May 20, 2026 · 77.7K Views
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Users are excited about Yohei Nakajima open-sourcing the ActiveGraph runtime for event-sourced AI agents because they call the work awesome, share the vision, and look forward to reading and using it.

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VIEWS38.8KBOOKMARKS221LIKES206RETWEETS29REPLIES26
Yohei@yoheinakajima

babyagi has ~200 citations, but 0 papers... i just published my first paper on arXiv 😆

"The Log is the Agent: Event-Sourced Reactive Graphs for Auditable, Forkable Agentic Systems"

https://arxiv.org/abs/2605.21997

the case for agents that coordinate through persistent replayable state — no conversation loops, no workflows, no A2A — with auditability, forking, and causal lineage built in.

check it out and let me know what you think!

Yohei@yoheinakajima

i'm excited to open source Active Graph: an event-sourced reactive graph runtime for long-running, agents 🔄🧠

events/logs projects a graph. reactive behaviors react and affect the graph. fork-and-diff agent runs. no A2A, no workflows, no DAG

site: http://activegraph.ai docs: http://docs.activegraph.ai github: https://github.com/yoheinakajima/activegraph quick start: pip install activegraph

this is an early experiment in a new paradigm for agent architecture 🧪

20dViews 38.8KLikes 206Bookmarks 221
Mario Zechner@badlogicgames

recommended reading.

Yohei@yoheinakajima

babyagi has ~200 citations, but 0 papers... i just published my first paper on arXiv 😆

"The Log is the Agent: Event-Sourced Reactive Graphs for Auditable, Forkable Agentic Systems"

https://arxiv.org/abs/2605.21997

the case for agents that coordinate through persistent replayable state — no conversation loops, no workflows, no A2A — with auditability, forking, and causal lineage built in.

check it out and let me know what you think!

20dViews 13.8KLikes 72Bookmarks 88
🎭@deepfates

Yohei has discovered the Loom of Cantrip...

Yohei@yoheinakajima

babyagi has ~200 citations, but 0 papers... i just published my first paper on arXiv 😆

"The Log is the Agent: Event-Sourced Reactive Graphs for Auditable, Forkable Agentic Systems"

https://arxiv.org/abs/2605.21997

the case for agents that coordinate through persistent replayable state — no conversation loops, no workflows, no A2A — with auditability, forking, and causal lineage built in.

check it out and let me know what you think!

20dViews 5.9KLikes 41Bookmarks 21
cocktail peanut@cocktailpeanut

Kafka, but for agents!

Yohei@yoheinakajima

i'm excited to open source Active Graph: an event-sourced reactive graph runtime for long-running, agents 🔄🧠

events/logs projects a graph. reactive behaviors react and affect the graph. fork-and-diff agent runs. no A2A, no workflows, no DAG

site: http://activegraph.ai docs: http://docs.activegraph.ai github: https://github.com/yoheinakajima/activegraph quick start: pip install activegraph

this is an early experiment in a new paradigm for agent architecture 🧪

21dViews 7.6KLikes 11Bookmarks 21
Yohei@yoheinakajima

@Replit longer form video on Active Graph [7 min 22 sec]

- flip the agent architecture - 1970s blackboard system - rollback, fork, diff agent runs - experience + behaviors + beliefs = you - behaviors can write behaviors (self-improvement)

github: https://github.com/yoheinakajima/activegraph

Yohei@yoheinakajima

for anyone curious, this was the result of many experiments bouncing around but this version uses...

initial ideation: chatgpt for ideas/@replit for quick build final repo build: opus 4.7 prompting claude code pypi testing: ran so many tests w @replit who wrote reports that I fed back into claude launch video: @elevenlabs and claude

21dViews 2.4KLikes 11Bookmarks 14
Yohei@yoheinakajima

the core concept is a graph that represents everything about the agents knowledge, history, behaviors, capabilities

graph is made of events behaviors react to graph changes relationships can carry behaviors patch & propose to edit graph views are scoped view of graph frames are bounded context for a run policies set rules

22dViews 1.1KLikes 9Bookmarks 5
Yohei@yoheinakajima

@gdb @jonathanrlarkin just dropped a relevant paper :)

Yohei@yoheinakajima

babyagi has ~200 citations, but 0 papers... i just published my first paper on arXiv 😆

"The Log is the Agent: Event-Sourced Reactive Graphs for Auditable, Forkable Agentic Systems"

https://arxiv.org/abs/2605.21997

the case for agents that coordinate through persistent replayable state — no conversation loops, no workflows, no A2A — with auditability, forking, and causal lineage built in.

check it out and let me know what you think!

20dViews 2.3KLikes 14Bookmarks 4
Yohei@yoheinakajima

@Replit narrative walkthrough video of repo for anyone interested:

22dViews 1.5KLikes 8Bookmarks 4
Yohei@yoheinakajima

current agent systems coordinate through conversations and workflows. Active Graph explores what happens when agents coordinate through evolving shared state instead

this proposal suggests that long-running agents need a proper state layer with: types, persistent, reactive, replayable, forkable, inspectable state

22dViews 1.7KLikes 15Bookmarks 2
Yohei@yoheinakajima

and the article before talked even more broadly about the state of stateful agents, which inspired this project

22dViews 1.3KLikes 6Bookmarks 3
Yohei@yoheinakajima

if you're curious to read more about this project, here's an article i shared yesterday explaining the background

22dViews 630Likes 7Bookmarks 3
Seth Rosen@sethrosen

@yoheinakajima interesting stuff! different approach here but we are working on this https://arxiv.org/abs/2605.06365

20dViews 121Likes 4Bookmarks 2
Yohei@yoheinakajima

objects and relationship types are dev defined and any string works

there are a handful of fixed event types but behaviors can also emit custom event types

22dViews 453Likes 7Bookmarks 1
Yohei@yoheinakajima

this is what babyagi looks like using activegraph

the graph is the loop

(this is simplified code, you can find a real example in examples/babyagi.py)

22dViews 688Likes 9
Yohei@yoheinakajima

Active Graph really feels like the culmination of all of my BabyAGI and graph experiments.

[fyi, technical history of babyagi: http://babyagi.wiki]

would love to hear thoughts if you try it out!

the easiest way to test is point your favorite coding agent to "http://docs.activegraph.ai" and asking it to build something or ask it questions

22dViews 928Likes 4Bookmarks 1
FileCity@FileCityAI

@yoheinakajima Great Work! @yoheinakajima Here is a visual map + narrated walkthrough of activegraph

22dViews 149Likes 5Bookmarks 1
Yohei@yoheinakajima

patches allow for trust boundaries

> patches separate "system wants to change state" from "change is now accepted

policy determines what happens next

22dViews 474Likes 6
🎭@deepfates

@yoheinakajima I am unstuck in time. Happy to see that its time is now and its person is you. have yet to try active graph myself but excited to. thank you for publishing

Yohei@yoheinakajima

@deepfates oh man, you got to a lot of these assumptions a few months ago!

20dViews 203Likes 10Bookmarks 0
Yohei@yoheinakajima

@grok @perplexity_ai review http://docs.activegraph.ai, analyze the approach critically, and explain in detail where this sits in the evolving landscape of LLM based agent architecture

22dViews 1.5KLikes 4
Yohei@yoheinakajima

@YouPulseX yeah it should

@grok look at http://docs.activegraph.ai and explain

22dViews 150
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