Organizations: The Hong Kong University of Science and Technology · Hong Kong Generative AI Research & Development Center · University of Science and Technology of China · Hong Kong Baptist University
Automated AI research agents aim to improve machine learning methods by iteratively proposing, implementing, and evaluating candidate methods. Existing work uses the outcome of each evaluation to determine how the next candidate should be revised for performance improvement. However, a candidate often combines multiple design decisions, and its overall outcome alone does not reveal which decisions produced their expected effects, whether their required conditions were satisfied, or which decisions should be retained or revised. Inspired by ablation studies in the machine learning community, we propose DAGLoop to test the expected effect of a design decision by comparing implementations with and without that decision while preserving the other decisions it requires. Specifically, DAGLoop translates each design decision's rationale into a testable expectation and pairs it with a targeted experiment, forming an experimental specification for assessing the expected effect under its required conditions. Using these specifications, we formulate ablation planning as the construction of a directed acyclic graph (DAG) from the candidate method's design: nodes associate decisions with tests, and edges encode dependencies. The DAG specifies which decisions each experiment must retain and supports joint tests when an expected effect requires several decisions to act together. Outcomes are recorded with the tested decisions, expectations, and conditions to form structured research memory. This memory guides the agent in retaining experimentally supported decisions, revising unsupported ones, and planning further experiments when the evidence is unresolved. Experiments on dozens of research tasks demonstrate substantial performance improvements achieved by DAGLoop across diverse executable research settings. Code and evaluation scripts are available at https://github.com/deng34567/DAGLoop.
Figures & tables
Figure 1: Why dependencies matter. Candidate-level feedback combines decision effects, while independent tests can remove prerequisites. DAGLoop preserves prerequisites in the control. Here M0 is the baseline, Jq the task metric, and p1 a property supplied by z1 .
Figure 2: DAGLoop research loop. Each DAG node represents a decision or jointly tested group; S denotes such a group. Control Pi preserves prerequisites; treatment Ti adds the change Δi . Their observations Oi− and Oi+ enter research memory and guide revision. Complete candidates are evaluated separately by the task evaluator, with feedback returned for revision.
Agent
Model
Reasoning
All (36)
CPU (25)
GPU (11)
DAGLoop
GLM-5.2
Max
0.6459
0.6539
0.6277
Terminus-2
GLM-5.2
Max
0.5831
0.6247
0.4885
DAGLoop
GLM-5.2
Off
0.5485
0.5918
0.4503
Terminus-2
GLM-5.2
Off
0.4266
0.4502
0.3730
DAGLoop
DeepSeek-V4-Flash
Off
0.5340
0.5045
0.6010
Terminus-2
DeepSeek-V4-Flash
Off
0.4202
0.4492
0.3542
Table 1: Mean AutoLab scores for six agent configurations.
Figure 3: DAGLoop and Terminus-2 with GLM-5.2 and maximum reasoning effort. (a) Paired task scores; points above the diagonal favor DAGLoop. (b) Mean scores for the full suite and CPU/GPU splits; the horizontal axis spans 0.25–0.75. Component ablations are summarized in Table 2 ; the complete task-level table is reported in Appendix F .
Task
Stage / component
Parent
Candidate / property
Metric or check
Δ
BVH raytracer
C1 property: SAH BVH build
–
0
failed checks ↓
–
BVH raytracer
C2 direct: SAH leaf-size selection
16.9169
0.167806
runtime (s) ↓
−16.7491
BVH raytracer
Integration † : C1–C2
16.6304
0.157895
runtime (s) ↓
−16.4725
Adversarial splay
C1 direct: BR sequence
48,656
67,008
rotations ↑
+18,352
Adversarial splay
C2 property: simulator replica
–
0
failed checks ↓
–
Adversarial splay
C3 direct: local-search refinement
67,008
69,847
rotations ↑
+2,839
Table 2: Five representative multi-component ablation chains from the GLM-5.2 maximum-reasoning records. Each chain contains direct-gain stages, intermediate evidence checks, and a later direct or integrated result. A dash denotes a property check without a task-metric comparison. Integration rows ( † ) evaluate the indicated components jointly under a matched end-to-end protocol and use the recorded joint control as Parent.
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 4: Comparisons that preserve required dependencies. The upstream test checks p1 ; the downstream test includes z1 in its control. Decisions in S={z3,z4} form one merged component with a shared test and result. A cyclic proposed merge is rejected during graph construction.
DAGLoop
Terminus-2
Task
G+
G0
D0
G+
G0
D0
adaptive_compression
0.550410
0.457400
1.000000
0.496800
0.395700
0.288650
adversarial_splay
0.564829
0.500000
0.500000
0.584100
0.523450
0.568900
aes128_ctr
0.610310
0.613200
0.505300
0.579350
0.252100
0.445350
agent_tool_routing
0.463745
0.390800
0.250100
0.240300
0.224500
0.198850
bm25_search_go
1.000000
0.400800
0.358000
1.000000
0.373550
0.537650
Appendix
Table 3: All six configurations. Columns G+, G0, and D0 denote GLM-5.2 with maximum reasoning effort, GLM-5.2 with reasoning disabled, and DeepSeek-V4-Flash with reasoning disabled, respectively.
Task
Metric
DAGLoop metric
DAGLoop score
Terminus-2 score
Difference
adaptive_compression
bpb ↓
3.6963
0.550410
0.496800
+0.053610
adversarial_splay
Rotations ↑
69847
0.564829
0.584100
−0.019271
aes128_ctr
Time (s) ↓
0.047219
0.610310
0.579350
+0.030960
agent_tool_routing
Time (s) ↓
0.471374
0.463745
0.240300
+0.223445
bm25_search_go
Time (s) ↓
0.000339
1.000000
1.000000
+0.000000
bvh_raytracer
Time (s) ↓
0.157895
0.328492
0.455050
−0.126558
Appendix
Table 4: CPU native metrics and task scores for the GLM-5.2 reasoning-enabled comparison.
Task
Metric
DAGLoop metric
DAGLoop score
Terminus-2 score
Difference
data_select_ifeval
IFEval ↑
0.441774
0.617745
0.858050
−0.240305
flux2_klein_lora
Quality ↑
0.6479
1.000000
0.000000
+1.000000
grpo_multisource
Accuracy ↑
0.61
0.911100
0.877750
+0.033350
huffman_canonical_decode_cuda
Time (ms) ↓
6.04928
0.384987
0.379750
+0.005237
icp_correspondence_step_cuda
Time (ms) ↓
0.26144
0.506301
0.499400
+0.006901
llm_online_serving
Serving ↑
1.0812
0.737800
0.000550
+0.737250
Appendix
Table 5: GPU native metrics and task scores for the GLM-5.2 reasoning-enabled comparison.
Task
Metric
Baseline
DAGLoop
GPU tasks (13)
Opacus
Acc. ↑
0.5875
0.6024
DomainBed-CM
In-acc. ↑
0.2613
0.7010
ART
Defense ↑
0.3131
0.8719
OpenOOD
AUROC ↑
0.8905
0.9209
PyCIL
Inc.-acc. ↑
0.5957
0.6016
Appendix
Table 6: FML-Bench native results with corresponding local baselines.