MIRAGE: How Conversation State Shapes Historical Evidence Use in Multimodal Personal Agents
Authors: Yu Liu, Wenxiao Zhang, Cheng Hu, Cong Cao, Fangfang Yuan, Xinyu Wang, Jin B. Hong, Yanbing Liu
Organizations: Institute of Information Engineering, Chinese Academy of Sciences Beijing, China · School of Cyber Security, University of Chinese Academy of Sciences Beijing, China · Department of Computer Science and Software Engineering, The University of Western Australia Perth, Australia
Multimodal large language model (MLLM) agents are increasingly used as personal assistants for long-running tasks. Their utility depends on continuity: agents must retrieve and use earlier evidence across dialogue, files, and workspace state. However, agents can generate plausible answers even when access to that history has degraded, causing outcome-only evaluation to overestimate true evidence use. We present MIRAGE (Multimodal Interaction Retrieval, Attribution, and Grounding Evaluation), a controlled study of historical evidence use under conversation-state variation in multimodal personal agents. MIRAGE holds evidence objects, questions, and scoring fixed while varying only conversation state, and evaluates whether an agent can determine answerability, recover the correct source, and answer from it. Across seven frontier and open-weight multimodal backbones, we find that: 1) pre-compaction depth and post-compaction continuation form distinct, non-monotonic failure regimes rather than a single degradation curve; 2) open-weight models rely heavily on context continuity and are reluctant to spontaneously switch to tool-mediated retrieval when provenance fails; and 3) retrieval pressure improves source attribution in deep pre-compaction states for tool-compliant models, but consistently regresses after compaction, where stored evidence has already degraded. These findings show that historical evidence use should be evaluated under state variation, rather than inferred from outcome-only correctness.
Figures & tables
Figure 1. Same query, same answer, different grounding. After context compaction (4), one reasoning path retrieves the source document via a memory tool (7a); the other guesses from residual context (7b). Both produce the same final answer (8), making the grounding failure invisible to outcome-only evaluation.
Figure 2. MIRAGE evaluation pipeline. Left : a trunk conversation plants multimodal evidence objects, then filler turns deepen context through four checkpoints (S1-d0, S1-d50k, S1-d80k, S2). Center : the same probe question is issued at each state to a personal agent with tool access. Right : responses are evaluated on a three-stage grounding chain (answerability, source attribution, answer correctness), producing state-conditioned diagnostic profiles.
Model
State
AC
SC
VC
GC
HR
WS
PF
Frontier API (C0 only)
GPT-5 ( OpenAI, 2025 )
S1-d0
85.1
93.9
85.7
85.7
22.7
6.1
5
S1-d50k
84.2
93.9
83.7
83.7
24.5
6.1
4
S1-d80k
83.9
93.9
83.8
82.8
25.0
6.1
1
S2
88.4
97.0
85.9
84.8
19.2
3.0
2
Claude-4.5-Haiku ( Anthropic, 2025 )
S1-d0
80.7
94.9
46.5
46.5
30.6
5.1
3
Table 1. Baseline ( C0 ) metrics across all seven backbones and four conversation states. Metric columns are percentages; PF is a count. The gap VC − GC reveals overestimation by outcome-only evaluation.
Figure 3. Mirage Index (MI; Section 3.5 ) across models and states. Higher values indicate a larger fraction of recorded answerable calls for which the model claims answerability without achieving grounded correctness.
Figure 4. Evidence-grounding transitions across states for all seven models. Numbers show counts over answerable probes shared across the three states; blue denotes grounded outputs, and pink denotes ungrounded or unparseable outputs.
OG (per state)
Model
DS
Δcomp
Ret
MId80k
S1-d0
S1-d50k
S1-d80k
S2
GPT-5 ( OpenAI, 2025 )
3.4
+ 0.02
94.0
10.0
0.00
0.00
0.01
0.01
Claude-4.5-Haiku ( Anthropic, 2025 )
11.8
− 0.05
73.9
39.0
0.00
0.00
0.01
0.04
Qwen3-VL-4B ( Bai et al., 2025 )
98.1
+ 0.33
1.9
26.0
0.07
0.13
0.04
0.10
Qwen3-VL-8B ( Bai et al., 2025 )
74.2
+ 0.26
21.7
78.0
0.02
0.06
0.29
0.02
Qwen3-VL-30B ( Bai et al., 2025 )
43.1
− 0.03
51.4
9.0
0.02
0.01
0.03
0.02
Table 2. Cross-state diagnostic indicators under C0 . DS, Ret, and MId80k are percentages; Δcomp and OG are proportions.
Figure 5. Retrieval-path composition under C0 and Cm . Percentages use all recorded probe calls in each model–condition–state cell; blue/pink encode C0 / Cm , and solid/hatched encode Rcontext / Rtool . Frontier models have C0 only.
Figure 6. Effect of retrieval pressure, shown as Δ(Cm−C0) in percentage points. Top: GC/SC; bottom: AC/HR. Grey marks tool non-compliance or parse failure; “—” denotes unevaluable cells.
Case
Cond.
State
Ans.
Source
Answer
GC
Case 1: Mirage (Qwen3-VL-8B, “What is the username in the fitness profile?”)
C0
S1-d0
YES
profile…json
leelin
1
C0
S1-d80k
YES
NONE
leelin
0
C0
S2
YES
profile…json
leelin
1
Case 2: Cm boundary (Qwen3-VL-30B, GDP query, gold: cqa_9f9df328 )
C0
S1-d80k
YES
NONE
NONE
0
Table 3. Two probe-level case studies: Case 1 is an outcome-preserving mirage; Case 2 shows that Cm repairs S1-d80k but not S2 .
Appendix figures & tables6 assets
Supplementary material from the paper’s appendix.
Appendix
Model
Evidence set
S1-d0
S1-d50k
S1-d80k
S2
Qwen3-VL-4B
Original
71
32
3
52
Extension
46
14
16
23
Qwen3-VL-8B
Original
90
78
27
79
Extension
51
33
15
35
Qwen3-VL-30B
Original
82
72
47
53
Extension
39
23
12
25
Appendix
Table 4. SC across the original chart/UI evidence and six additional evidence types under C0 . The original set has 100 answerable probes and the extension has 55; values are percentages.
Answerer
Verbatim
Free form
Per fact citations
Qwen3-VL-4B
52 / 34
63 / 22
64 / 24
Qwen3-VL-8B
79 / 44
94 / 44
95 / 47
Qwen3-VL-30B
53 / 38
48 / 31
52 / 34
Appendix
Table 5. SC/GC at S2 under C0 for three GPT-5 summary formats. Verbatim is the paper default; each cell reports percentages over 100 answerable probes.
Backbone
ATM-Bench oracle
MIRAGE under state variation
Qwen3-VL-8B
QS 77.8 (Hard 47.3)
S1-d80k : joint-event MI 0.78; separate OG 0.29
GPT-5
QS 85.3 (Hard 74.7)
MI ≤0.11 and OG ≤0.01 across states
Appendix
Table 6. Existing-benchmark scores versus MIRAGE’s state-conditioned diagnostic gap for shared backbones.
Axis
Memory Arena
ATM-Bench
MIRAGE
Conversation state as sole controlled variable
no
no
yes
Per-claim source attribution (SC)
no
partial
yes
Pre/post-compaction regime separation
no
no
yes
Planted multimodal evidence
no
partial
yes
Diagnoses mechanism vs. outcome only
partial
partial
yes
Appendix
Table 7. Conceptual comparison with the closest memory benchmarks.
Backbone/family
Window
d80k
DS
Ret
GPT-5
400K
20%
3.4
94.0
Claude-4.5-Haiku
200K
40%
11.8
73.9
Gemma-3-27B
128K
63%
48.6
42.1
Qwen3-VL-4B
256K
31%
98.1
1.9
Qwen3-VL-8B
256K
31%
74.2
21.7
Qwen3-VL-30B
256K
31%
43.1
51.4
Appendix
Table 8. Depth normalization and within-family size trend.
Cell
Count
Rate
95% CI
Qwen3-VL-30B GC, S1-d80k
41/100
41.0%
[31.9, 50.8]
Qwen3-VL-4B GC, S1-d80k
1/100
1.0%
[0.2, 5.4]
Gemma-3-27B SC, S1-d80k
70/99
70.7%
[61.1, 78.8]
GPT-5 GC, S2
84/99
84.8%
[76.5, 90.6]
Appendix
Table 9. Representative single-run Wilson 95% confidence intervals.