AriGraph: Learning Knowledge Graph World Models with Episodic Memory for LLM Agents

AuthorsPetr Anokhin, Nikita Semenov, Artyom Sorokin et al.

2024

TL;DR

AriGraph links semantic and episodic memories in a unified knowledge graph world model, enabling Ariadne to match NetPlay’s 675.33 vs 593.00 NetHack score while using only local observations.

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THE PROBLEM

LLM agents with unstructured memory fail in complex text games

LLM agents typically rely on full history, summarization, or RAG, but these unstructured memories “do not facilitate the reasoning and planning essential for complex decision-making.”

In TextWorld and NetHack, this causes agents to miss scattered clues and outdated facts, so they cannot reliably navigate, plan, or complete long-horizon tasks.

HOW IT WORKS

AriGraph world model with semantic and episodic memory

AriGraph centers on a semantic memory graph, episodic memory vertices, semantic search, episodic search, and the Ariadne cognitive architecture for planning and decision making.

You can think of AriGraph like a hippocampus-backed card catalog: semantic memory is the catalog of facts, while episodic memory stores richly detailed pages linked to those facts.

This key design lets AriGraph retrieve structured world state and precise past observations, enabling reasoning and exploration that a plain context window or flat vector store cannot support.

DIAGRAM

AriGraph retrieval pipeline for decision making

This diagram shows how AriGraph runs semantic and episodic search to populate working memory before Ariadne chooses an action.

DIAGRAM

Evaluation setup across TextWorld, NetHack, and Q&A

This diagram summarizes how AriGraph is evaluated on TextWorld games, NetHack variants, and multi-hop Q&A benchmarks against LLM and RL baselines.

PROCESS

How AriGraph Handles an Interactive TextWorld Episode

  1. 01

    AriGraph world model learning

    AriGraph receives the new observation and uses semantic memory and episodic memory to add vertices and edges capturing objects and relations.

  2. 02

    Memory graph search

    AriGraph runs semantic search and episodic search over the graph to retrieve relevant triplets and past observations for the current situation.

  3. 03

    Planning stage

    Within the Ariadne cognitive architecture, the planning module uses working memory plus retrieved knowledge to generate or update a structured plan of sub goals.

  4. 04

    Decision making

    The ReAct based decision making module in Ariadne reads the plan and working memory, then selects an action aligned with AriGraph’s world model.

KEY CONTRIBUTIONS

Key Contributions

  • 01

    AriGraph world model

    AriGraph defines a unified semantic memory and episodic memory graph G = (V_s, E_s, V_e, E_e) that is incrementally learned from textual observations in interactive environments.

  • 02

    Ariadne cognitive architecture

    Ariadne integrates AriGraph with planning and decision making, enabling LLM agents to solve Treasure Hunt, Cleaning, and Cooking games that defeat full history, summarization, RAG, Simulacra, and Reflexion baselines.

  • 03

    Cross domain evaluation

    AriGraph is evaluated in TextWorld, NetHack, and multi hop Q&A, achieving a NetHack score of 593.00 with room observations and 68.0 EM on HotpotQA using GPT 4.

RESULTS

By the Numbers

NetHack Score

593.00

+251.33 over NetPlay (Room obs)

NetHack Levels

6.33

+2.66 over NetPlay (Room obs)

HotpotQA EM

68.0

+13.0 over GPT-4 full context

MuSiQue EM

45.0

equal to HOLMES baseline EM 48.0 within 3.0 points

These metrics come from NetHack and the MuSiQue and HotpotQA benchmarks, which test exploration, long horizon reasoning, and multi hop question answering. The results show that AriGraph lets Ariadne nearly match a memory oracle on NetHack and reach 68.0 EM on HotpotQA while using a general purpose world model.

BENCHMARK

By the Numbers

These metrics come from NetHack and the MuSiQue and HotpotQA benchmarks, which test exploration, long horizon reasoning, and multi hop question answering. The results show that AriGraph lets Ariadne nearly match a memory oracle on NetHack and reach 68.0 EM on HotpotQA while using a general purpose world model.

BENCHMARK

NetHack performance with and without AriGraph world model

Average NetHack game score across three runs for different agents.

KEY INSIGHT

The Counterintuitive Finding

Ariadne with AriGraph and only room observations reaches a NetHack score of 593.00, close to NetPlay’s 675.33 with full level observations.

This is surprising because one would expect removing handcrafted level observations to cripple performance, yet AriGraph’s learned world model nearly closes the 82.33 point gap.

WHY IT MATTERS

What this unlocks for the field

AriGraph shows that LLM agents can learn structured world models online, combining semantic and episodic memory for long horizon reasoning and exploration.

Builders can now design agents that operate in partially observable environments like NetHack or TextWorld without handcrafted state or massive context windows, while still supporting multi hop Q&A over accumulated experience.

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