EMemBench: Interactive Benchmarking of Episodic Memory for VLM Agents

AuthorsXinze Li, Ziyue Zhu, Siyuan Liu et al.

2026

TL;DR

EMemBench uses an experience-conditioned benchmark generator with programmatic QA templates to show A-MEM reaches 51.9% ACC on text games vs 44.9% for Qwen3-32B in-context (+7.0 points).

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THE PROBLEM

Memory agents still struggle with induction and spatial reasoning in EMemBench

EMemBench reveals that induction peaks at only 34.2 ACC on text games and 20.2 ACC on visual games, with visual spatial best at 24.3 ACC.

These low scores mean VLM agents fail to form reliable episodic memory for induction and spatial reasoning, limiting long-term decision making in interactive environments.

HOW IT WORKS

EMemBench: Experience-conditioned benchmark generator

EMemBench centers on Interaction episode, Benchmark generator, Structured logging, State reconstruction, and Programmatic QA generation to turn each agent’s trajectory into QA instances.

Think of EMemBench like a game engine plus a black-box recorder and an auto-grader: it logs everything the agent sees and does, then computes ground truth from underlying game signals.

This KEY_MECHANISM lets EMemBench test individualized episodic memory over dynamic environments, rather than static long-context reasoning within a single prompt window.

DIAGRAM

Interactive episode-to-QA pipeline in EMemBench

This diagram shows how EMemBench converts an agent’s interaction episode into a QA set with deterministic ground truth and metadata.

DIAGRAM

EMemBench evaluation setup across text and visual games

This diagram shows how EMemBench runs text-only and visual games, applies query horizon control, and aggregates accuracy across seeds.

PROCESS

How EMemBench Handles an Interaction episode

  1. 01

    Interaction episode

    EMemBench records an Interaction episode as a sequence of observations, actions, and rewards while the agent plays Jericho or Crafter.

  2. 02

    Game State Collection

    EMemBench performs Structured logging of each timestep, capturing scores, coordinates, inventory, player view, and achievements as JSON.

  3. 03

    State reconstruction

    EMemBench builds a Timeline index and Event index to reconstruct higher level events like inventory changes and location transitions efficiently.

  4. 04

    Programmatic QA Generation

    EMemBench applies the Benchmark generator and Programmatic QA generation templates to create balanced, answerable questions with deterministic ground truth.

KEY CONTRIBUTIONS

Key Contributions

  • 01

    Experience-conditioned memory evaluation framework

    EMemBench defines Interaction episode and Benchmark generator to turn each agent’s own trajectory into QA, supporting individualized episodic memory evaluation across 16 environments and infinite trajectories.

  • 02

    Programmatic QA generation with controlled answerability

    EMemBench uses Structured logging, State reconstruction, and Programmatic QA generation templates to cover seven abilities, including single hop, multi hop, induction, spatial, temporal, logical, and adversarial reasoning.

  • 03

    Query horizon control and stability analysis

    EMemBench introduces query horizon control and reports low seed standard deviations (e.g., 0.0364 ACC SD for GPT-5.1 on text games), ensuring fair and reproducible comparisons between memory agents.

RESULTS

By the Numbers

Overall ACC

51.9%

+7.0 over Qwen3-32B in-context

Single-Hop ACC

66.9%

+17.9 over Qwen3-32B in-context

Multi-Hop ACC

28.1%

-4.6 vs Qwen3-32B in-context

Visual Overall ACC

43.8%

best in-context score for GPT-5.1 on visual games

These metrics come from EMemBench’s main results table on text-only and visual games, which test seven memory abilities across Jericho and Crafter. The 51.9% Overall ACC for A-MEM with Qwen3-32B on text games shows EMemBench can quantify gains from persistent memory modules over pure in-context prompting baselines.

BENCHMARK

By the Numbers

These metrics come from EMemBench’s main results table on text-only and visual games, which test seven memory abilities across Jericho and Crafter. The 51.9% Overall ACC for A-MEM with Qwen3-32B on text games shows EMemBench can quantify gains from persistent memory modules over pure in-context prompting baselines.

BENCHMARK

Main results on text-only games for Qwen3-32B

Overall ACC on EMemBench text games for Qwen3-32B with different memory settings.

KEY INSIGHT

The Counterintuitive Finding

EMemBench shows that memory agents can reduce Single-Hop accuracy for GPT-5.1, where in-context Single-Hop ACC is already 76.7% but some memory variants drop below this.

This is surprising because persistent memory is expected to help all question types, yet EMemBench reveals that adding retrieval and organization can hurt simple recall when the backbone’s prompt-based memory is already strong.

WHY IT MATTERS

What this unlocks for the field

EMemBench unlocks a way to stress-test episodic memory as an interactive, individualized competence, not just long-context reading over static logs.

With EMemBench, builders can now design and compare memory agents that must survive dynamic text and visual games, revealing nuanced trade-offs between in-context reasoning and persistent memory modules.

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