EvoGraph-Mem: Failure-Aware Editable Graph Memory for Long-Term Language Agents

AuthorsYuxi Qian, Yuxiang Ren

arXiv 20262026

TL;DR

EvoGraph-Mem adds failure-aware editable insight nodes with positive and negative evidence, yielding 47.47 avg score vs 43.23 for G-Memory (+4.24).

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THE PROBLEM

Long-term agents suffer memory pollution from outdated insights

EvoGraph-Mem targets the issue that append-only memory is insufficient for long-horizon tasks, where reused insights become outdated, conflicting, or harmful.

When polluted memories are repeatedly retrieved, long-term language agents face degraded reasoning quality and task performance across evolving tasks and environments.

HOW IT WORKS

EvoGraph-Mem — Failure-aware editable insight graph

EvoGraph-Mem combines a Graph-Based Historical Memory, an Insight Graph, Utility-Aware Insight Retrieval, and a Graph Controller for Memory Correction to maintain insight-level validity.

You can think of EvoGraph-Mem like a library card catalog that not only files books but also flags, revises, or archives misleading entries over time.

This design lets EvoGraph-Mem selectively reuse only well-supported insights, something a plain context window or append-only memory cannot safely guarantee.

DIAGRAM

Failure-aware retrieval and correction flow

This diagram shows how EvoGraph-Mem retrieves insights with evidence-aware scoring and then edits the insight graph after task execution.

DIAGRAM

Evaluation setup across PDDL, HotpotQA, and FEVER

This diagram shows how EvoGraph-Mem is evaluated on three benchmarks and compared against memory-based baselines.

PROCESS

How EvoGraph-Mem Handles a Long-Term Task

  1. 01

    Graph-Based Historical Memory

    EvoGraph-Mem first builds the Graph-Based Historical Memory with a structured Query Graph and Insight Graph over past tasks and interactions.

  2. 02

    Utility-Aware Insight Retrieval

    Given a new query, EvoGraph-Mem performs Utility-Aware Insight Retrieval, scoring candidates by positive evidence st,k and conflict penalty λ ct,k.

  3. 03

    Failure-Aware Insight Representation

    During execution, EvoGraph-Mem uses Failure-Aware Insight Representation with Ω+ k, Ω− k, and activation state zk to track how each insight behaves.

  4. 04

    Graph Controller for Memory Correction

    After task feedback, the Graph Controller for Memory Correction issues KEEP, ARCHIVE, REVISE, and ADD operations to evolve the Insight Graph.

KEY CONTRIBUTIONS

Key Contributions

  • 01

    Insight-level memory maintenance

    EvoGraph-Mem formalizes insight-level memory maintenance, showing append-only memory is insufficient and linking polluted insights to degraded long-horizon performance on PDDL, HotpotQA, and FEVER.

  • 02

    Editable insight graph

    EvoGraph-Mem introduces an editable Insight Graph where each node stores positive evidence Ω+ k, negative evidence Ω− k, and activation state zk for failure-aware retrieval.

  • 03

    Graph controller for memory correction

    EvoGraph-Mem adds a Graph Controller for Memory Correction that issues KEEP, ARCHIVE, REVISE, and ADD operations, yielding a 21.75 exact match gain on HotpotQA over the no-memory baseline with GPT-4o-mini.

RESULTS

By the Numbers

PDDL progress rate GPT-4o-mini

30.67

+2.90 over G-Memory

HotpotQA exact match GPT-4o-mini

43.43

+7.76 over G-Memory

FEVER exact match GPT-4o-mini

68.32

+2.08 over G-Memory

Average score GPT-4o-mini

47.47

+4.24 over G-Memory

On PDDL, HotpotQA, and FEVER, EvoGraph-Mem is evaluated using progress rate and exact match accuracy, directly testing long-horizon planning and multi-hop reasoning. The 47.47 vs 43.23 average score with GPT-4o-mini shows EvoGraph-Mem converts corrective memory maintenance into consistent benchmark gains over G-Memory.

BENCHMARK

By the Numbers

On PDDL, HotpotQA, and FEVER, EvoGraph-Mem is evaluated using progress rate and exact match accuracy, directly testing long-horizon planning and multi-hop reasoning. The 47.47 vs 43.23 average score with GPT-4o-mini shows EvoGraph-Mem converts corrective memory maintenance into consistent benchmark gains over G-Memory.

BENCHMARK

Performance comparison of different memory methods on PDDL, HotpotQA, and FEVER datasets (GPT-4o-mini Avg.)

Average score across PDDL, HotpotQA, and FEVER with GPT-4o-mini.

BENCHMARK

Average token consumption across PDDL, HotpotQA, and FEVER

Average token consumption for GPT-4o-mini across all benchmarks.

KEY INSIGHT

The Counterintuitive Finding

EvoGraph-Mem increases average token usage to 6.4M on GPT-4o-mini, a 73.0% rise over the 3.7M no-memory baseline.

Despite this overhead, EvoGraph-Mem still improves the average score from 36.41 to 47.47, challenging the assumption that tighter token budgets always yield better efficiency–performance trade-offs.

WHY IT MATTERS

What this unlocks for the field

EvoGraph-Mem unlocks long-term agents that can not only remember but also correct, archive, and refine their own high-level insights over time.

Builders can now deploy language agents whose external memory evolves through explicit KEEP, ARCHIVE, REVISE, and ADD operations, avoiding memory pollution in complex, evolving task streams.

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