MetaExp: Learning to Self-Improve through Experience via Verifiable Cross-Task Environment Scaling
Authors: Renhao Li, Xinjie Shen, Yang Su, Jianhong Tu, Derek F. Wong, Dayiheng Liu, Min Yang
Organizations: University of Macau · Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences · Georgia Institute of Technology · Alibaba Token Hub, Alibaba Group
Language-model agents can accumulate interaction feedback, but reliably turning that feedback into reusable experience remains challenging. Existing methods either optimize external experience scaffolds or train experience-related behavior on specific task distributions, leaving open whether experience learning itself can become a transferable model capability. Training such a capability calls for supervision beyond isolated tasks, which mainly support in-episode problem solving rather than revealing what knowledge remains useful across episodes. In this work, we introduce MetaExp, a scalable framework that trains this capability through verifiable task families with controlled cross-task structure. Each family preserves a reusable factor while varying task-specific realizations, enabling transfer without direct solution reuse. We propose two complementary designs: Shared-Tool families keep black-box tools fixed across tasks to elicit operational experience, while Shared-Workflow families preserve latent procedures across changing realizations to elicit procedural experience. We scale environments under both designs, collect and filter sequential interaction trajectories, and fine-tune Qwen3.5-122B-A10B on 4,956 trajectories from 1,000 task families. With parameters frozen during downstream evolution, MetaExp improves by +8.5 points on SpreadsheetBench, peaks at +2.3 on APEX-Agents, and improves by +14.8 on AutomationBench. The gains persist under domain-excluded training, supporting experience learning as a transferable capability for continued non-parametric improvement after deployment.
Figures & tables
Figure 1: Overview of MetaExp . Heterogeneous seeds are expanded into verifiable task families with complementary Shared-Tool and Shared-Workflow structure. Family-centered task sequences are used to collect execution and feedback-driven reflection trajectories, which train the model to acquire, update, and reuse experience. At evaluation, model parameters are frozen and experience is accumulated from an empty bank on unseen task distributions.
Model
Protocol
k=0
k=5
k=10
k=20
k=40
Task success rate (%, ↑ )
GPT-4.1
EvoSkill
44.2
–
–
–
37.2±2.6(−7.0)
GPT-5.4
EvoSkill
62.5
–
–
–
68.1±0.5(+5.6)
GPT-4.1
SkillGrad
44.2
–
–
–
54.2±3.5(+10.0)
GPT-5.4
SkillGrad
62.5
–
–
–
71.1±1.7(+8.6)
GLM-5.2
SeqEvo
88.3±1.2
88.9±0.5(+0.6)
89.5±0.7(+1.2)
89.6±0.4(+1.3)
89.4±0.4(+1.1)
Table 1: Performance and efficiency on SpreadsheetBench. Values are mean ± population standard deviation, with Δk=S(k)−S(0) shown in parentheses. Green/red denotes improvement/degradation relative to k=0 . EvoSkill and SkillGrad results are taken from Wang et al. (2026a) and follow their originally reported evolution protocols; all other results use our cold-start SeqEvo protocol. “–” denotes an unreported checkpoint.
Figure 2: Performance on APEX-Agents and AutomationBench. Left: aggregate success rate over adaptation steps, with shaded population standard deviations over three runs. Right: domain-wise success rate and changes Δk on each adaptation step for MetaExp -Qwen3.5-122B-A10B and Qwen3.5-122B-A10B; green/red denotes improvement/degradation.
Model
k=0
k=5
k=10
k=20
k=40
Task success rate (%, ↑ )
Qwen3.5-122B-A10B
68.9±1.8
67.3±1.8(−1.6)
67.7±0.5(−1.2)
67.0±0.9(−1.9)
66.7±1.3(−2.2)
- MetaExp
65.0±2.2
69.5±3.3(+4.5)
72.9±3.7(+7.9)
73.1±2.8(+8.1)
73.5±3.4(+8.5)
- Strict-OOD MetaExp
62.7±1.4
66.8±5.0(+4.1)
66.2±4.0(+3.5)
72.5±3.0(+9.8)
72.0±0.8(+9.3)
Table 2: SpreadsheetBench task success under domain-excluded training. Values are mean ± population standard deviation over three runs, with Δk=S(k)−S(0) shown in parentheses.
Model
Score (%)
Pass (%)
GLM-5.2
65.1
74.7
Baseline
33.3
47.1
MetaExp
41.4 (+8.1)
62.1 (+15.0)
Table 3: Model performance on SkillsBench. Values are averaged across three runs.
Benchmark
Shared-Tool Only
Shared-Workflow Only
Full MetaExp
Initial
Final
Initial
Final
Initial
Final
Task success rate (%, ↑ )
SpreadsheetBench
62.7±1.0
72.4±7.3(+9.7)
63.6±1.5
69.7±2.7(+6.1)
65.0±2.2
73.5±3.4(+8.5)
APEX-Agents
13.2±1.3
12.7±1.3(−0.5)
12.2±0.6
12.6±0.7(+0.4)
12.2±1.7
14.0±1.4(+1.8)
AutomationBench
7.2±0.5
14.8±3.8(+7.6)
8.5±0.5
15.6±3.6(+7.1)
14.5±0.9
29.3±3.3(+14.8)
Execution turns ( ↓ )
Table 4: Ablation of cross-family task designs on models. Values are mean ± population standard deviation over three runs, with Δ=Sfinal−Sinitial shown in parentheses.
Model
Condition
Skills in bank
Any invocation (%)
Skill as first tool (%)
Calls/task
Baseline-Qwen3.5
k=5
3.0±0.0
9.3±2.0
2.4±1.3
0.094±0.021
k=10
5.3±0.5
11.3±2.5
4.2±1.5
0.113±0.025
k=20
10.0±0.0
18.6±4.7
7.8±0.1
0.188±0.049
k=40
10.0±0.0
17.0±8.2
5.0±2.6
0.172±0.084
MetaExp -Qwen3.5
k=5
2.0±0.8
76.4±16.4
63.1±23.2
0.765±0.162
k=10
3.3±2.6
79.5±16.9
67.0±23.0
0.800±0.164
Table 5: SpreadsheetBench experience-access behavior. Values are means ± population standard deviations over three seeds.
Model
Conditions
Invoked skill
Did not invoke
Baseline-Qwen3.5
All k pooled
−4.2
−1.2
MetaExp -Qwen3.5
All k pooled
+9.5
−1.9
MetaExp -Qwen3.5
k=20
+10.8±4.7
−0.3±4.8
MetaExp -Qwen3.5
k=40
+10.2±6.4
−4.7±6.7
Table 6: Paired success-rate change relative to the same task under an empty-bank condition (%).
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Metric
Baseline-Qwen3.5
MetaExp -Qwen3.5
Skills
30
14
Lexical tokens
29,679
31,155
Tokens per skill
989.3
2,225.4
Failure terms / 1K tokens
1.42
5.42
Verification terms / 1K tokens
3.13
4.56
Opaque IDs / 1K tokens
2.26
0.00
Appendix
Table 7: Structure of the final SpreadsheetBench skill banks at k=40 , pooled over three seeds.
Case
Baseline-Qwen3.5
MetaExp -Qwen3.5
Cross-sheet lookup
A local VLOOKUP/INDEX–MATCH recipe with several formula variants and a recommendation to write static values.
A symptom–cause–repair–verification taxonomy covering truncated ranges, wrong-sheet references, hidden whitespace, cached formula values, and cell-level validation.
Boundary-sensitive editing
A generic checklist: preserve values, use absolute references, handle missing keys, and verify the output.
Conditional diagnostic rules for inflated worksheet bounds and locale-dependent formula separators, tied to observable failure signals and corrective checks.
Appendix
Table 8: Case study on how different models encode experiences on SpreadsheetBench.
Figure 3: Domain distribution of corpus seeds under Shared-Tool and Shared-Workflow construction.
Figure 4: Primary-intent distribution of the task-example seeds used in MetaExp .
Figure 5: Capability distribution of tool examples and their coverage across seed records.