Video world models are increasingly used as simulators for planning and embodied decision making, yet improving them at inference time introduces a subtle evaluation problem: prompts, samplers, verifiers, and selectors may evolve together, making it difficult to attribute gains or prevent held-out feedback from shaping the final policy. We introduce \scope (\scopefullname), a framework for auditable inference-time adaptation of frozen video world models. \scope represents external controls as a typed state, updates this state only through bounded changes supported by development evidence, and freezes the resulting policy before held-out evaluation. On Physics-IQ benchmark, \scope improves over the exact frozen base by +14.24 (95% CI [+8.10,+21.23]). Controlled ablations further identify gains from scene specification, sampling, and learned selection, while the margin over the strongest matched agentic baseline remains unresolved. Cross-backbone and prospective evaluations reveal a complementary result: useful inference-time updates exist, but their benefits do not transfer uniformly across models and settings. Together, these findings suggest that reliable inference-time adaptation requires not only better proposals, but also a principled mechanism for deciding which updates should become part of the deployed system. Code is available at https://github.com/YuhuaJiang2002/SCOPE.
Figures & tables
Figure 1: Overview of Scope . Proposal mechanisms in the gray band are replaceable. Scope maintains (1) a typed state over text, noise, verifier, and reward controls; (2) a score-blind deployment choice with an exact Base fallback; (3) a development-time state update that accepts or rejects bounded edits; and (4) a score-isolation constraint that keeps held-out outcomes read-only. Only the external inference state changes; model weights remain frozen.
Method
Wan P-IQ
Wan Δ (95% CI)
CogVideoX P-IQ
CogVideoX Δ (95% CI)
Frozen Base
20.70
–
22.91
–
WMReward reward-only ( Yuan et al., 2026 )
21.81
+1.11[−0.40,+3.17]
26.10
+3.19[+0.85,+6.04]
VAE- θ reward
22.33
+1.63[−0.67,+4.46]
25.14
+2.23[+0.02,+4.83]
VIGOR reward-only ( Yin et al., 2026 )
25.15
+4.44[+1.49,+7.96]
27.75
+4.83[+1.71,+8.44]
uniform random 3-candidate selector ( Brown et al., 2024 ; Ma et al., 2025 )
27.41
+6.71[+1.93,+11.45]
30.57
+7.65[+4.51,+10.97]
LingBot-style Director → Pilot proxy † ( Gao et al., 2026 )
29.98
+9.27[+2.37,+16.12]
34.91
+12.00[+6.76,+17.62]
Table 1: Common-base Physics-IQ comparison across two frozen video backbones. All rows report the mean over 40 scene-level Physics-IQ composites. Within each backbone, methods share the same Base and evaluation protocol. The Scope –Qwen differences are +2.07 on Wan (CI [−0.27,+6.14] ) and +0.52 on CogVideoX (CI [−0.39,+1.65] ), and remain unresolved on both backbones. Absolute scores are not compared across backbones. The dagger denotes the separately generated fixed Director baseline; green indicates Base-relative intervals with positive lower bounds.
Figure 2: Evolution of the matched Physics-IQ policy across two frozen backbones. R0–R3 correspond to Base, the physics-card update, the rule-refinement update, and the final selected Scope state. Curves show the mean Physics-IQ score over 40 scenes, with shaded 95% scene-bootstrap confidence intervals. Scores are compared only within each backbone.
Figure 3: Example of retrieval-assisted generation on Newton’s cradle. Retrieval provides a textual concept card but no reference pixels or visual embeddings. Both Wan2.2 variants use the same temporal anchoring operation. The visualization for OURS additionally includes the disclosed endpoint-motion intervention and display-only hand replacements. This example is qualitative and is not used as evidence for the aggregate tool-use effect.
Matched method
Wan Overall
Wan Δ (95% CI)
CogVideoX Overall
CogVideoX Δ (95% CI)
Ranking-eligible matched methods
Frozen Base
76.67
–
74.10
–
+ shared global
76.86
+0.19 CI [−2.13,+2.66]
74.41
+0.30 CI [−2.15,+2.77]
LingBot-style Director → Pilot + shared global †
76.77
+0.10 CI [−2.25,+2.54]
74.29
+0.18 CI [−2.30,+2.69]
Qwen-Image-Agent-style (SceneLang)
77.02
+0.35 CI [−1.50,+2.32]
74.72
+0.62 CI [−1.37,+2.68]
SceneLang + shared global
77.01
+0.34 CI [−1.86,+2.63]
71.57
−2.53 CI [−5.25,+0.12]
Table 2: Cross-backbone results on P-AI (PAI-Bench-G). Deltas and paired 95% CIs are relative to the Frozen Base of the same backbone. SceneLang is the strongest fixed-policy comparator. The diagnostic Scope rows report the better of two variants per backbone and therefore do not represent a single transferable policy.
Method
Wan Mean †
Wan Weighted †
CogVideoX Mean †
CogVideoX Weighted †
Frozen Base ( Team Wan et al., 2025 ; Yang et al., 2025 )
37.46
36.60
48.30
48.29
Qwen-Image-Agent-style ( Zhang et al., 2026c )
38.72
37.92
46.73
46.16
LingBot-style Director → Pilot prompt proxy ‡ ( Gao et al., 2026 )
41.27
42.84
47.39
49.62
GPT-5.4 first-frame skill (internal)
38.31
39.33
46.67
47.99
Scope (ours)
41.75
43.17
47.76
49.22
Table 3: Cross-backbone results on OpenS2V-Eval ( n=180 per backbone). Scores are multiplied by 100 and compared only within each backbone. Mean † and Weighted † use the disclosed GPT-5.4 judge with a Qwen fallback proxy. ‡ denotes a prompt-only LingBot-style proxy.
Evaluation
Reference / Criterion
Outcome
Fresh Physics-IQ
Base
+0.096[−0.887,+1.077]
Frozen router
−1.019[−2.159,+0.146]
Typed update
Random update
−0.316[−5.984,+5.145]
Tool router
Always-on
+0.660[+0.016,+1.315]
No tool
+0.083[−0.191,+0.381]
Random routing
+0.002[−0.281,+0.299]
Table 4: Prospective evaluations. Positive effects favor the proposed method; PhyGround reports proposal coverage against its predeclared minimum.
Category
Variant
Comparison
Δ (95% CI)
Control
Text (SceneLang)
vs. Base
+5.62[+0.55,+10.55]
Noise
vs. fixed sampler
+1.26[+0.52,+2.01]
Reward
vs. matched random
+3.33[+1.49,+5.30]
Reward
vs. self-score
+0.66[−1.52,+2.92]
Region-state prior
identity metric
−7.28[−13.33,−2.53]
Update
Random update
vs. Ω0
+4.53[+1.14,+9.17]
Table 5: Ablation studies of Scope . Each row reports a matched comparison and its 95% CI. Component effects are protocol-specific and should not be added across rows.
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Policy
Cards
Target
Confirmation
Pooled
Exact no-tool
0
0.4071
0.4425
0.4189
Always-on profiled card
180
0.4021
0.4352
0.4132
Fit-only group policy
48
0.4096
0.4401
0.4197
Same-budget stratified random
48
0.4084
0.4424
0.4197
Appendix
Table 6: Selective grounded-router final result. Absolute DisMo cosine similarities reuse the same two candidate arms and three seeds for all four policies. Cards count profiled prompt-card applications across 192 target and 96 confirmation tasks; they are not additional generated videos.
Result
Evaluation role
Authoritative artifact(s)
Matched 40-scene Physics-IQ procedure vs exact Base
same-universe system result
physiq_common_base_result.json ; matched publication in the release manifest
Retrospective LingBot harness proxy
same-protocol retrospective addition
matched score evidence and result in the release manifest
Table 7: Result-to-artifact index. Each row links a reported experimental result to its smallest authoritative machine-readable source.
Setting
Independent unit
Evaluation role
Primary comparison
GPT-5.4 SceneLang
scene; 3 fixed seeds averaged
component evidence
SceneLang vs Base; CI conditional on these seeds
Learned reward
64 scenes; 179 nested views
component evidence
scene-grouped OOF reward vs matched random
Physics-IQ tool axis
scene; 3 nested views
preregistered negative ablation
web-only and web+SAM vs no-tool; incremental SAM vs web-only
PAI split6
task
same-split deployment diagnostic
all matched controls shown; post-hoc Scope separated
OpenS2V
category-stratified item
prospective deployment case
Scope vs LingBot; unresolved
Fresh PhyT2V evaluation
scene
deployment diagnostic
selected vs incumbent/fixed proposal; no expansion credit
Appendix
Table 8: Protocol and statistical status matrix. Views are nested within scenes for Physics-IQ; secondary, same-split, and post-hoc rows never receive promotion credit.
Method
SC
BC
MS
AQ
IQ
OC
IS
IB
Frozen base (absolute)
89.51
91.71
98.49
44.21
62.83
19.50
92.44
95.75
Shared global (Base parent)
-0.45
-0.18
-0.73
+0.61
+1.60
-0.12
-0.09
-0.02
Qwen-Image-Agent-style (SceneLang) ( Zhang et al., 2026c )
LingBot-style Director → Pilot + shared global † ( Gao et al., 2026 )
-0.16
+0.02
-0.70
+0.70
+2.17
-0.22
+0.06
+0.07
Appendix
Table 9: Complete official-72B PAI quality profiles. SC/BC are subject/background consistency; MS is motion smoothness; AQ/IQ are aesthetic/imaging quality; OC is overall text–video consistency; IS/IB are I2V subject/background fidelity. Frozen Base is absolute and all other rows are Δ vs Base. All 12 main-panel rows are included.
Figure 4: Web-grounded complete paper submersion intervention. Both rows use the same straw-free seed- 20260785 Wan2.2 baseline. The unexplained overhead straw is inpainted once in their shared conditioning frame. WITHOUT OURS shows the complete baseline frame, in which only the lower paper edge contacts the water. OURS applies a disclosed post-hoc full-frame intervention: the complete paper mask is compressed onto the dish bottom; every final paper pixel lies within the audited water ellipse; and water tint, caustics, refraction, and a ripple band are rendered after the paper. Both published A/B MP4s and the displayed frames are complete 832×480 images, with dish cropping disabled in the manifest. The post-absorption Wikimedia image is display-only and never enters either video. Retrieved pixels likewise never enter the video. The native four-seed prompt grid failed the qualitative gate and is not shown. This visualization is a qualitative post-hoc state intervention, not native Wan dynamics, an unbiased generation result, or benchmark evidence.