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Agents / Reinforcement Learning

Teaching AI Agents to Simulate Their World

Original: EnvACE: Internalizing Environment Dynamics via World Rehearsal for Agentic Reinforcement Learning

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Key Takeaways

  • Eliminates reliance on external, costly simulation environments by using an internalized world model.
  • Utilizes a dual-role policy to generate both tool-calling actions and their corresponding environmental responses.
  • Achieves competitive performance with an overall score of 32.91% across multiple benchmarks.
  • Demonstrates superior tool-use capabilities in specialized domains, reaching a 46.78% F1 score on FinMCP-Bench.

Summary & Methodology Analysis

EnvACE addresses the challenge of building agents for long-horizon tasks, where dependency on external tool-use environments often introduces latency and complex infrastructure requirements. The system optimizes a single shared policy that operates in two roles: an acting role that issues tool calls, and a rehearsal role that predicts the resulting system output based on interaction history. This internal loop essentially mimics a sandbox environment, allowing the agent to perform private rehearsals before committing to an external execution. The roles are optimized using Group Relative Policy Optimization (GRPO), a reinforcement learning technique that improves policy stability by normalizing rewards across a group of samples.

Interactive System Flowchart

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Cross-Examination & FAQs

A deeper dive clarifying mechanics, constraints, and baseline evaluations.

Q1. What is the main problem this paper solves?

It solves the dependency on costly, complex external simulators when training agents for long-horizon tool use.

Q2. How does EnvACE avoid using a live simulator?

It internalizes environment dynamics into the agent's parameters, allowing the agent to simulate responses internally via a rehearsal role.

Q3. What kind of performance improvement does this approach offer?

It outperforms existing environment-scaling baselines, achieving an overall score of 32.91% across specified benchmarks and a 46.78% F1 score on FinMCP-Bench.

Q4. What is the role of the rehearsal memory?

The rehearsal memory stores the results of internal simulations, which are used to condition the agent's final execution decision at test time.

Q5. How are the acting and rehearsal roles trained?

They are optimized end-to-end using task-success rewards via Group Relative Policy Optimization (GRPO).

Q6. Which models were used during the research?

The paper utilized various models including Qwen3 series (1.7B, 4B, and 8B), Simulator-8B, TOUCAN-7B, EnvScaler-8B, AWM (8B and 14B), and ScaleEnv-8B.

Q7. What are the limitations of the current evaluation?

Evaluations are limited to models up to 8B parameters and are primarily focused on tool-interactive tasks.

Q8. What datasets were used to validate the model?

The paper utilized BFCL-v4, τ 2-Bench, VitaBench, and FinMCP-Bench.

Q9. Does the paper specify the inference latency or hardware costs?

The paper does not specify these metrics.