GEM: A Gym for Agentic LLMs
On the map: LLM agents and tool use → Reinforcement learning for LLM agents
Abstract (arXiv)
The training paradigm for large language models (LLMs) is moving from static datasets to experience-based learning, where agents acquire skills via interacting with complex environments. To facilitate this transition we introduce GEM (General Experience Maker), an open-source environment simulator designed for the age of LLMs. Analogous to OpenAI-Gym for traditional reinforcement learning (RL), GEM provides a standardized framework for the environment-agent interface, including asynchronous vectorized execution for high throughput, and flexible wrappers for easy extensibility. GEM also features a diverse suite of environments, robust integrated tools, and single-file example scripts demonstrating using GEM with five popular RL training frameworks. Along with this, we also provide a set of baselines across 24 environments using REINFORCE with Return Batch Normalization (ReBN), which -- unlike GRPO -- is compatible with the full RL setting of dense per-turn rewards and offers better credit assignment. We further conduct apple-to-apple benchmarking of PPO, GRPO and REINFORCE in both single- and multi-turn settings using GEM to shed light on the algorithmic designs. Lastly, GEM also functions as a convenient evaluation toolkit besides a training environment. We hope this framework can help accelerate future agentic LLM research.
Key facts. Cited by 23 papers in the map (data through 14 Oct 2026). Placed in Reinforcement learning for LLM agents, one of 16 directions in LLM agents and tool use. Builds on 29 of its 56 references that are in the map. First posted on arXiv 1 Oct 2025.
Builds on
29 of 56 references.
Closest ancestors · 4
Same direction, newest first
- 2025SimpleTIR: End-to-End Reinforcement Learning for Multi-Turn Tool-Integrated Reasoning2 Sep
- 2025SPIRAL: Self-Play on Zero-Sum Games Incentivizes Reasoning via Multi-Agent Multi-Turn Reinforcement Learning30 Jun
- 2025Group-in-Group Policy Optimization for LLM Agent Training16 May
- 2025ReTool: Reinforcement Learning for Strategic Tool Use in LLMs15 Apr
Other references · 25
- 2022Training language models to follow instructions with human feedbackcited by 15,971
- 2017Proximal Policy Optimization Algorithmscited by 15,215
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- 2023Efficient Memory Management for Large Language Model Serving with PagedAttentioncited by 5,944
- 2025Qwen2.5-VL Technical Reportcited by 5,587
- 2019Fine-Tuning Language Models from Human Preferencescited by 2,150
- 2024HybridFlow: A Flexible and Efficient RLHF Frameworkcited by 2,057
- 2015High-Dimensional Continuous Control Using Generalized Advantage Estimationcited by 2,026
- 2025Search-R1: Training LLMs to Reason and Leverage Search Engines with Reinforcement Learningcited by 1,444
- 2024τ-bench: A Benchmark for Tool-Agent-User Interaction in Real-World Domainscited by 1,402
- 2025Understanding R1-Zero-Like Training: A Critical Perspectivecited by 1,345
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- 2024Tulu 3: Pushing Frontiers in Open Language Model Post-Trainingcited by 1,053
- 2023Beyond Human Data: Scaling Self-Training for Problem-Solving with Language Modelscited by 349
- 2019OpenSpiel: A Framework for Reinforcement Learning in Gamescited by 186
- 2024VinePPO: Refining Credit Assignment in RL Training of LLMscited by 183
- 2018Deep Reinforcement Learning and the Deadly Triadcited by 174
- 2025ReSearch: Learning to Reason with Search for LLMs via Reinforcement Learningcited by 161
- 2025A Minimalist Approach to LLM Reasoning: from Rejection Sampling to Reinforcecited by 145
- 2025REASONING GYM: Reasoning Environments for Reinforcement Learning with Verifiable Rewardscited by 130
- 2025Reinforcement Learning Optimization for Large-Scale Learning: An Efficient and User-Friendly Scaling Librarycited by 101
- 2023LMRL Gym: Benchmarks for Multi-Turn Reinforcement Learning with Language Modelscited by 88
- 2023TorchRL: A data-driven decision-making library for PyTorchcited by 60
- 2022MARLlib: A Scalable and Efficient Multi-agent Reinforcement Learning Librarycited by 21
- 2024Open RL Benchmark: Comprehensive Tracked Experiments for Reinforcement Learningcited by 17
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Citing papers per year: 2025: 3; 2026: 20.
23 papers.
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- 2025SkyRL-Agent: Efficient RL Training for Multi-turn LLM Agentcited by 48
- 2026Rethinking the Trust Region in LLM Reinforcement Learningcited by 37
- 2026ProRL Agent: Rollout-as-a-Service for RL Training of Multi-Turn LLM Agentscited by 20
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- 2026LOCA-bench: Benchmarking Language Agents Under Controllable and Extreme Context Growthcited by 14
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- 2026Agentic ESOpt: Fine-Tuning Long-Horizon LLM Agents with Minimal GPU Requirements18 Aug 2026
- 2026LatentGym: A Testbed For Cross-Task Experiential Learning With Controllable Latent Structure13 Jun 2026
- 2026Agentic Environment Engineering for Large Language Models: A Survey of Environment Modeling, Synthesis, Evaluation, and Application10 Jun 2026
- 2026Verifiable Process Rewards for Agentic Reasoning11 May 2026
11 more
- 2026Towards Autonomous Business Intelligence via Data-to-Insight Discovery Agent8 May 2026
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- 2026On Training Large Language Models for Long-Horizon Tasks: An Empirical Study of Horizon Length4 May 2026
- 2026ProRL Agent: Rollout-as-a-Service for RL Training of Multi-Turn LLM Agents19 Mar 2026
- 2026Gym-V: A Unified Vision Environment System for Agentic Vision Research16 Mar 2026
- 2026RetroAgent: From Solving to Evolving via Retrospective Dual Intrinsic Feedback9 Mar 2026
- 2026LOCA-bench: Benchmarking Language Agents Under Controllable and Extreme Context Growth8 Feb 2026
- 2026Rethinking the Trust Region in LLM Reinforcement Learning4 Feb 2026
- 2025Scaling Agentic Reinforcement Learning for Tool-Integrated Reasoning in VLMs24 Nov 2025
- 2025SkyRL-Agent: Efficient RL Training for Multi-turn LLM Agent20 Nov 2025
- 2025Environment Scaling for Interactive Agentic Experience Collection: A Survey12 Nov 2025
- 2025SkyRL-Agent: Efficient RL Training for Multi-turn LLM Agentcited by 48
- 2026ProRL Agent: Rollout-as-a-Service for RL Training of Multi-Turn LLM Agentscited by 20
- 2026LOCA-bench: Benchmarking Language Agents Under Controllable and Extreme Context Growthcited by 14
- 2025Environment Scaling for Interactive Agentic Experience Collection: A Surveycited by 13
- 2026Agentic Environment Engineering for Large Language Models: A Survey of Environment Modeling, Synthesis, Evaluation, and Applicationcited by 8
- 2026Gym-V: A Unified Vision Environment System for Agentic Vision Researchcited by 3
- 2026Agentic ESOpt: Fine-Tuning Long-Horizon LLM Agents with Minimal GPU Requirementscited by 3
- 2026LatentGym: A Testbed For Cross-Task Experiential Learning With Controllable Latent Structurecited by 2
- 2026Harbor Adapters and Harbor-Index: Infrastructure and a Curated Meta-Dataset for Large-Scale Agentic Evaluationcited by 1
- 2026Towards Autonomous Business Intelligence via Data-to-Insight Discovery Agentcited by 0
- 2026Environments as Scaffold: Enriching Feedback to Bootstrap Self-Evolving Agents in Long-Horizon Taskscited by 0
- 2026ProCredit: From Outcome Rewards to Progress Credit in Agentic Reinforcement Learningcited by 0
12 most cited of 14 All 14 (JSON)
- 2026InvestigationWorlds: An Agentic Environment for Legal Investigation2 Oct 2026
- 2026NeutronGym: Physics-Graded Neutron Instrument Design for LLM Agents2 Oct 2026
- 2026ProCredit: From Outcome Rewards to Progress Credit in Agentic Reinforcement Learning23 Sep 2026
- 2026Environments as Scaffold: Enriching Feedback to Bootstrap Self-Evolving Agents in Long-Horizon Tasks8 Sep 2026
- 2026Harbor Adapters and Harbor-Index: Infrastructure and a Curated Meta-Dataset for Large-Scale Agentic Evaluation3 Sep 2026
- 2026Agentic ESOpt: Fine-Tuning Long-Horizon LLM Agents with Minimal GPU Requirements18 Aug 2026
- 2026LatentGym: A Testbed For Cross-Task Experiential Learning With Controllable Latent Structure13 Jun 2026
- 2026Agentic Environment Engineering for Large Language Models: A Survey of Environment Modeling, Synthesis, Evaluation, and Application10 Jun 2026
- 2026Towards Autonomous Business Intelligence via Data-to-Insight Discovery Agent8 May 2026
- 2026ProRL Agent: Rollout-as-a-Service for RL Training of Multi-Turn LLM Agents19 Mar 2026
- 2026Gym-V: A Unified Vision Environment System for Agentic Vision Research16 Mar 2026
- 2026LOCA-bench: Benchmarking Language Agents Under Controllable and Extreme Context Growth8 Feb 2026
12 newest of 14 All 14 (JSON)
- 2026RetroAgent: From Solving to Evolving via Retrospective Dual Intrinsic Feedbackcited by 17
- 2026On Training Large Language Models for Long-Horizon Tasks: An Empirical Study of Horizon Lengthcited by 6
- 2026CASCADE: Case-Based Continual Adaptation for Large Language Models During Deploymentcited by 1
- 2026BACAM: Behavior-Aware Continual Agent Merging for Multi-Turn Interactioncited by 0
- 2026Sherpa: Teaching LLMs to Teach Adaptivelycited by 0
- 2026Sherpa: Teaching LLMs to Teach Adaptively6 Oct 2026
- 2026BACAM: Behavior-Aware Continual Agent Merging for Multi-Turn Interaction4 Oct 2026
- 2026CASCADE: Case-Based Continual Adaptation for Large Language Models During Deployment5 May 2026
- 2026On Training Large Language Models for Long-Horizon Tasks: An Empirical Study of Horizon Length4 May 2026
- 2026RetroAgent: From Solving to Evolving via Retrospective Dual Intrinsic Feedback9 Mar 2026
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