[2605.21997] The Log is the Agent: Event-Sourced Reactive Graphs for Auditable, Forkable Agentic Systems

# Computer Science > Artificial Intelligence **arXiv:2605.21997** (cs) \[Submitted on 21 May 2026\] # Title:The Log is the Agent: Event-Sourced Reactive Graphs for Auditable, Forkable Agentic Systems Authors: [Yohei Nakajima](https://arxiv.org/search/cs?searchtype=author&query=Nakajima,+Y) View a PDF of the paper titled The Log is the Agent: Event-Sourced Reactive Graphs for Auditable, Forkable Agentic Systems, by Yohei Nakajima [View PDF](https://arxiv.org/pdf/2605.21997) [HTML (experimental)](https://arxiv.org/html/2605.21997v1) > Abstract:Most agent frameworks are built around the language model: a conversation loop comes first, then tools, then rules, and finally a logging layer bolted on for observability, with state persisted as retrievable "memory." We describe ActiveGraph, a runtime that inverts this arrangement. The append-only event log is the source of truth; the working graph is a deterministic projection of that log; and behaviors--ordinary functions, classes, LLM-backed routines, or logic attached to typed edges--react to changes in the graph and emit new events. No component instructs another; coordination happens entirely through the shared graph. This single design decision yields three properties that retrieval-and-summarization memory systems do not provide: deterministic replay of any run from its log, cheap forking that branches a run at any event without re-executing the shared prefix, and end-to-end lineage from a high-level goal down to the individual model call that produced each artifact. We present the architecture, a determinism contract that makes replay sound, and a worked diligence example whose full causal structure is reconstructable from the log alone. We discuss--without claiming to demonstrate--why this substrate is unusually well suited to self-improving agents, and how it extends the BabyAGI lineage and prior graph-memory research. | | | | --- | --- | | Comments: | 11 pages, 1 figure. Open-source Apache-2.0 implementation with reproducible quickstart demo, deterministic replay, fork-and-diff, and lineage tracing | | Subjects: | Artificial Intelligence (cs.AI); Multiagent Systems (cs.MA) | | Cite as: | [arXiv:2605.21997](https://arxiv.org/abs/2605.21997) \[cs.AI\] | | | (or [arXiv:2605.21997v1](https://arxiv.org/abs/2605.21997v1) \[cs.AI\] for this version) | | | [https://doi.org/10.48550/arXiv.2605.21997](https://doi.org/10.48550/arXiv.2605.21997)<br>Focus to learn more<br>arXiv-issued DOI via DataCite (pending registration) | ## Submission history From: Yohei Nakajima \[ [view email](https://arxiv.org/show-email/c5ef03da/2605.21997)\] **\[v1\]** Thu, 21 May 2026 04:55:38 UTC (55 KB) Full-text links: ## Access Paper: View a PDF of the paper titled The Log is the Agent: Event-Sourced Reactive Graphs for Auditable, Forkable Agentic Systems, by Yohei Nakajima - [View PDF](https://arxiv.org/pdf/2605.21997) - [HTML (experimental)](https://arxiv.org/html/2605.21997v1) - [TeX Source](https://arxiv.org/src/2605.21997) [view license](http://arxiv.org/licenses/nonexclusive-distrib/1.0/ "Rights to this article") ### Current browse context: cs.AI [< prev](https://arxiv.org/prevnext?id=2605.21997&function=prev&context=cs.AI "previous in cs.AI (accesskey p)")  \|  [next >](https://arxiv.org/prevnext?id=2605.21997&function=next&context=cs.AI "next in cs.AI (accesskey n)") [new](https://arxiv.org/list/cs.AI/new) \| [recent](https://arxiv.org/list/cs.AI/recent) \| [2026-05](https://arxiv.org/list/cs.AI/2026-05) Change to browse by: [cs](https://arxiv.org/abs/2605.21997?context=cs) [cs.MA](https://arxiv.org/abs/2605.21997?context=cs.MA) ### References & Citations - [NASA ADS](https://ui.adsabs.harvard.edu/abs/arXiv:2605.21997) - [Google Scholar](https://scholar.google.com/scholar_lookup?arxiv_id=2605.21997) - [Semantic Scholar](https://api.semanticscholar.org/arXiv:2605.21997) export BibTeX citation ### Bookmark [](http://www.bibsonomy.org/BibtexHandler?requTask=upload&url=https://arxiv.org/abs/2605.21997&description=The%20Log%20is%20the%20Agent:%20Event-Sourced%20Reactive%20Graphs%20for%20Auditable,%20Forkable%20Agentic%20Systems "Bookmark on BibSonomy") [](https://reddit.com/submit?url=https://arxiv.org/abs/2605.21997&title=The%20Log%20is%20the%20Agent:%20Event-Sourced%20Reactive%20Graphs%20for%20Auditable,%20Forkable%20Agentic%20Systems "Bookmark on Reddit") Bibliographic Tools # Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer _( [What is the Explorer?](https://info.arxiv.org/labs/showcase.html#arxiv-bibliographic-explorer))_ Connected Papers Toggle Connected Papers _( [What is Connected Papers?](https://www.connectedpapers.com/about))_ Litmaps Toggle Litmaps _( [What is Litmaps?](https://www.litmaps.co/))_ scite.ai Toggle scite Smart Ci