HippoCamp: Benchmarking Contextual Agents on Personal Computers

AuthorsZhe Yang, Shulin Tian, Kairui Hu et al.

arXiv 20262026

TL;DR

HippoCamp benchmarks multimodal personal-computer agents with a hierarchical trajectory annotation schema, revealing only 48.3% profiling accuracy even for ChatGPT Agent Mode.

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THE PROBLEM

Agents Fail on Personal File Systems: Only 48.3% Profiling Accuracy

HippoCamp shows that even the strongest commercial system, ChatGPT Agent Mode, achieves only 48.3% profiling accuracy in realistic personal file systems.

These failures mean contextual agents cannot reliably perform personalized memory, cross-modal reasoning, or long-horizon user profiling on real device-scale environments.

HOW IT WORKS

HippoCamp — Hierarchical Supervision for Personalized Multimodal Memory

HippoCamp organizes supervision into Atomic Unit Annotations, Structured Trajectory Annotations, and Profiling QA Annotations plus Factual Retention QA Annotations with capability tags for search, perception, and reasoning.

Think of HippoCamp like a layered file cabinet: atomic snippets are folders, structured trajectories are labeled binders, and profiling questions are executive summaries over a lifetime of documents.

This hierarchy lets HippoCamp diagnose where agents fail—search, multimodal perception, or reasoning—far beyond what a flat context window or simple QA benchmark can reveal.

DIAGRAM

HippoCamp Query-to-Answer Flow in Personal File Systems

This diagram shows how a HippoCamp agent should search, perceive, and reason over a profile-local file system to answer a single benchmark query.

DIAGRAM

HippoCamp Data and Evaluation Pipeline

This diagram shows HippoCamp’s pipeline from real user data and interviews to archetypal profiles, QA trajectories, and unified evaluation.

PROCESS

How HippoCamp Handles a Personalized Question-Answer Trajectory

  1. 01

    Benchmark Scale

    HippoCamp first instantiates device-scale profiles with 42.4 GB and over 2K files across five modalities, defining the search space for all trajectories.

  2. 02

    Structured Trajectory Annotations

    HippoCamp converts each question into a structured trajectory with step-wise rationale, localized evidence, and 46.1K annotation units for fine-grained diagnosis.

  3. 03

    Factual Retention QA Annotations

    HippoCamp builds 521 factual retention questions that require agents to retrieve and reason over an average of 4 files and 2 modalities per question.

  4. 04

    Profiling QA Annotations

    HippoCamp adds 60 profiling questions that aggregate around 15 files and 3 modalities per query to test long-horizon personalized memory.

KEY CONTRIBUTIONS

Key Contributions

  • 01

    Realistic personal computing environments

    HippoCamp constructs three archetypal profiles—Bei, Adam, and Victoria—covering 42.4 GB and over 2K files with deep folder hierarchies and heterogeneous file types.

  • 02

    Device-scale corpus with dense supervision

    HippoCamp provides 581 QA pairs with 46.1K structured annotation units, including 4.6K step-wise rationales and 3.2K localized evidence annotations linked to atomic units.

  • 03

    Comprehensive agent capability evaluation

    HippoCamp evaluates search, perception, and reasoning via capability tags, revealing multimodal perception and evidence grounding as primary bottlenecks for current agents.

RESULTS

By the Numbers

Profiling Accuracy

48.3%

+22.5 over Standard RAG

Factual Retention Accuracy

62.8%

+32.8 over Standard RAG

Profiling F1

21.0

+2.6 over Standard RAG

Factual Retention F1

35.3

+5.3 over Standard RAG

On the HippoCamp benchmark, which tests multimodal search, perception, and reasoning over personal file systems, ChatGPT Agent Mode reaches 48.3% profiling accuracy and 62.8% factual retention accuracy. These results show that even the strongest evaluated agent leaves a large gap to robust personalized multimodal memory.

BENCHMARK

By the Numbers

On the HippoCamp benchmark, which tests multimodal search, perception, and reasoning over personal file systems, ChatGPT Agent Mode reaches 48.3% profiling accuracy and 62.8% factual retention accuracy. These results show that even the strongest evaluated agent leaves a large gap to robust personalized multimodal memory.

BENCHMARK

Main results on HippoCamp across user profiles

Overall factual retention accuracy (%) on HippoCamp for different methods.

KEY INSIGHT

The Counterintuitive Finding

HippoCamp shows that profiling accuracy collapses to just 5.0% for Search-R1, despite strong search F1 scores above 34% on profiling.

This is surprising because one might expect better retrieval to guarantee better answers, but HippoCamp reveals that post-retrieval perception and reasoning dominate failures.

WHY IT MATTERS

What this unlocks for the field

HippoCamp unlocks a way to stress-test agents on realistic, multimodal, device-scale personalized memory with interpretable, capability-wise diagnostics.

Builders can now design and benchmark file-system agents that explicitly tackle multimodal grounding, entity disambiguation, and verification, rather than optimizing only for retrieval or context length.

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