Puzzles offer a natural testbed for Large Language Models (LLMs) reasoning because they pose verifiable goals under partial information and require multi-step decisions to reach a solution. However, existing puzzle benchmarks typically focus on narrow environments with rigid mechanics and tightly constrained solution targets. To bridge this gap, we introduce the Active Probing Benchmark (APB), which generalizes puzzle-solving by casting concept identification as an interactive reasoning task that integrates specialized knowledge assessment into the puzzle setting. Specifically, APB evaluates whether models can acquire information via multi-turn active probing and inference to pinpoint 960 target concepts of specialized difficulty across eight diverse academic domains. Our evaluation reveals a counter-intuitive phenomenon: most open-source reasoning models significantly underperform their standard instruction counterparts. This finding suggests that in interactive settings, these models struggle to leverage procedural reasoning to reliably access and apply specialized domain knowledge. Beyond these empirical insights, APB provides a scalable pipeline for generating benchmarks that probe knowledge reasoning under interaction across diverse settings.
Figures & tables
Figure 1: Overview of the Active Probing Benchmark (APB) and representative performance results. (Left) Data construction : each puzzle specifies a target concept Ptarget drawn from a generalized knowledge source (e.g., Wikipedia or domain documents) along with a reference document Iref . (Middle) Multi turn active probing : the model under test iteratively asks multiple-choice queries Qt , receives feedback At from a knowledge oracle, and updates its hypotheses to reduce the candidate space until the target is identified or a turn budget is exhausted. (Right) Performance comparison : average success rates show that several open source “Thinking” models underperform their “No-Thinking” counterparts. Full results are reported in Table 2 .
Figure 2: Example episode from the Human Disease domain in APB, where the agent successfully identifies the target concept “Reticular dysgenesis”. Across turns, the agent acquires diagnostic evidence through queries and feedback, progressively narrowing the hypothesis set until the target is determined. The resulting interaction trace provides process-level evidence of how the model accesses and applies specialized knowledge.
Figure 3: The multi-stage, coarse-to-fine data filtering pipeline used to construct the Active Probing Benchmark from the English Wikipedia dump.
Group
N
Mean
Med.
Type
G1: Rejected (Stage 1)
1k
379.2
500 +
Common
G2: Rejected (Stage 4)
1k
86.7
19.0
Specialized
G3: Final (APB)
1k
59.3
16.0
Deep/Edge
Table 1: Topological Analysis of Concept Difficulty. In-link counts drop drastically, confirming the selection of “edge” knowledge.
Figure 4: Hierarchical distribution of puzzle targets across domains and sub-disciplines. Eight distinct color families represent the primary domains, while individual segments denote specific sub-topics. The area of each segment is proportional to the number of questions in that category. Exact distributions are provided in Appendix D .
Model
Bio
Dis
Chem
Phys
Math
CS
Econ
Phil
Avg.
GPT-5
34.2
37.5
33.3
34.2
34.2
25.0
39.2
30.0
33.4
Claude Opus 4
27.5
40.8
29.2
26.7
18.3
19.2
31.7
27.5
27.6
Claude Sonnet 4
29.2
35.0
23.3
23.3
17.5
18.3
42.5
21.7
26.4
o3
28.3
33.3
21.7
29.2
20.0
10.0
35.0
25.0
25.3
GPT-4o
26.7
24.2
20.0
17.5
11.7
10.8
25.0
20.8
19.6
Grok-4
14.2
30.8
16.7
13.3
10.0
13.3
20.8
21.7
17.6
Table 2: Success Rate (%) for various models across eight domains. The best performance in each domain is highlighted in bold . The bottom row, ’Domain Avg.’, summarizes the average performance for each domain.
Table 3: Detailed behavioral analysis metrics. PL : Probing Length, IG : Incorrect Guess rounds, IO : Incorrect Option rounds, IS : Incorrect Streak rounds, SR : Success Rounds, TR : Total Rounds. Blue bars visualize the normalized magnitude of each metric within its column to highlight behavioral patterns.
Figure 5: DeepSeek R1 reasoning trace for the target ’Reticular dysgenesis’ (Round 5). Top: The internal reasoning content shows the model brainstorming specific disease candidates following an incorrect guess. Middle: The extracted hypotheses visualize the diverse set of conditions considered during this step. Bottom: The generated follow-up question focuses on differentiating clinical features.
Appendix figures & tables12 assets
Supplementary material from the paper’s appendix.
Appendix
Synopsys
Cadence Innovus
Model
ICC
ICC2
Common
Legacy
Avg.
Claude Opus 4
27.5
14.2
16.7
22.5
20.2
GPT-5
25.8
15.0
14.2
20.0
18.8
grok-4
15.0
10.8
18.3
24.2
17.1
o3
20.0
15.0
12.5
12.5
15.0
Claude Sonnet 4
14.2
10.8
9.2
18.3
13.1
Appendix
Table 4: Success rates (%) on the IC Back-End Puzzle Benchmark. Tools are grouped by vendor: Synopsys (ICC, ICC2) and Cadence Innovus (Common, Legacy). “NT” denotes “No-Thinking”. Qwen3 models refer to the Qwen3-235B-A22B variants. Best results in each category are bolded .
Figure 6: Ranking consistency analysis (DeepSeek V3 vs. Claude Sonnet 4) across eight domains. Each point represents a model’s performance in a specific domain. The distinct clustering of model colors and the high Spearman’s rank correlation ( ρ ) within each domain confirm that relative model rankings remain robust despite the absolute score shift caused by the stricter judge.
Model
Configuration
Success Rate
Tier
Effect of Temperature (Open-Source Reasoning)
DeepSeek R1
Temp = 0.2 (Default)
6.7%
Bottom
Temp = 1.0 (Recommended)
8.3%
Bottom
Qwen3 Thinking
Temp = 0.2 (Default)
11.7%
Low
Temp = 0.6
10.8%
Low
Effect of Reasoning Effort (GPT-5)
Appendix
Table 5: Ablation results on sampling temperature and reasoning effort ( N=120 ). The “Tier” column reflects the relative ranking within the full benchmark context.
Model
QA
QA
QA Total
KO Comp.
Prompt
Comp.
Tok.
Tok.
(Best Performance)
GPT-5
9,821
24,301
34,122
430
(Most Verbosity)
GPT-OSS-120B
14,034
58,471
72,505
473
Qwen3 235B Think.
33,414
24,170
57,584
473
Appendix
Table 6: A summary of token usage for representative models. ”Comp.” stands for Completion, ”Tok.” for Tokens. KO output is low due to fixed formatting.