Beyond ReAct: A Planner-Centric Framework for Complex Tool-Augmented LLM Reasoning

Conference: AAAI 2026 arXiv: 2511.10037 Code: https://github.com/weixiaolong94-hub/Beyond-React Area: Agent / LLM Keywords: Tool-augmented LLM, DAG planning, Plan-Execute paradigm, GRPO reinforcement learning, multi-tool orchestration

TL;DR

This paper proposes a Planner-centric Plan-Execute framework that transforms complex queries into DAG-based execution plans. Through two-stage SFT+GRPO training of a dedicated Planner model, the approach surpasses reactive methods such as ReAct on ComplexTool-Plan and StableToolBench, achieving higher success rates with fewer inference steps.

Background & Motivation

Current tool-augmented LLMs rely primarily on reactive frameworks such as ReAct, which make decisions and execute actions incrementally. While viable for simple queries, this paradigm exhibits a fundamental deficiency on complex multi-tool composition tasks: the local optimum trap. Each decision attends only to the current state, lacking global planning capacity and failing to exploit inherent parallelism in task execution. Search-based methods such as Tree-of-Thought offer partial improvements but fundamentally still seek optimal sequential paths, incurring high computational overhead while ignoring parallelism.

Core limitations: 1. ReAct's incremental decision-making cannot model complex inter-tool dependencies. 2. Existing methods lack large-scale, structured training data for complex planning. 3. Evaluating planning quality is itself a non-trivial problem.

Core Problem

How can an LLM generate a globally optimal execution plan in a single pass for queries requiring multi-tool collaboration, rather than proceeding through trial and error? This paper casts the problem as: given query \(Q\) and tool set \(T\), learn a policy \(\pi\) that maps them to a DAG-structured execution plan \(G=(V,E)\).

Method

Overall Architecture

The framework consists of two decoupled phases—Planning and Execution: 1. The Planner receives the user query and available tool set, then generates a DAG execution plan (nodes = tools, edges = data dependencies). 2. The Executor (e.g., GPT-4o) executes tool calls in topological order of the DAG, supporting parallel execution of independent nodes.

Training pipeline: construct the ComplexTool-Plan dataset → SFT cold start → GRPO reinforcement fine-tuning.

Key Designs

1. ComplexTool-Plan Dataset Construction (three-stage automated pipeline):

   • Workflow generation: DeepSeek-V3 samples subsets from 4,535 ModelScope tool APIs and generates structurally complex DAG execution plans.
   • Query reverse engineering: DeepSeek-V3 back-generates natural language queries from DAGs, effectively "writing problems from answers."
   • Intent analysis and re-planning: A teacher model re-plans the DAG from the generated query alone, ensuring high fidelity of \((Q, G)\) pairs—samples where the query is too ambiguous to recover the original DAG are filtered out.

The final dataset contains 3,000 SFT instances across Easy/Medium/Hard difficulty levels. Higher difficulty implies a larger tool pool and more tools required per task.

1. DAG as a structured execution plan representation:

   • Nodes \(V \subseteq T\) represent selected tools.
   • Directed edges \(E\) represent data dependencies.
   • Parallel execution is supported: nodes without dependencies can be invoked simultaneously.
   • More expressive than linear sequences, enabling modeling of complex branching and merging logic.

2. RL training set refinement:

   • The SFT model is used to filter training data: instances the model already solves reliably (no learning signal) and those it completely fails on (too difficult) are removed.
   • The 787 retained high-variance instances focus training on the model's capability frontier, preventing policy degradation.

Loss & Training

Two-stage training:

Stage 1: SFT Cold Start NLL loss minimization on the Qwen3 series (0.6B/1.7B/4B/8B): $\(\mathcal{L}_{\text{SFT}}(\theta) = -\mathbb{E}_{(Q,G_{gt})\sim D_{\text{train}}}[\log P(G_{gt}|Q,T;\theta)]\)$

Stage 2: GRPO Reinforcement Learning A hierarchical reward function \(R(y)\) evaluates plan quality in strict priority order:

Level	Check	Reward/Penalty
Level 1	Syntax error (non-JSON format)	−10.0
Level 2	Cycle present (non-DAG)	−10.0
Level 3	Connectivity defect (isolated node)	−2.0
Level 4	Edge F1 score	\(5 \times\) Edge F1
Level 5	Perfect match bonus	+5.0

The reward range is \([-10.0,\ +10.0]\) with a fail-fast design: high-level penalties immediately terminate evaluation. The hierarchical design elegantly distinguishes structural errors (fatal) from policy errors (improvable), providing multi-dimensional gradient signals to the model.

Key Experimental Results

ComplexTool-Plan Planning Quality (Easy Set)

Method	Node F1	Edge F1	DAG EM
GPT-4o	0.929	0.779	0.635
Claude-3.7	0.949	0.815	0.644
DeepSeek-V3	0.770	0.643	0.511
Qwen3-0.6B (SFT)	0.968	0.848	0.671
Qwen3-1.7B (SFT+RL)	0.979	0.879	0.756
Qwen3-8B (SFT+RL)	0.984	0.906	0.803

ComplexTool-Plan Planning Quality (Hard Set)

Method	Node F1	Edge F1	DAG EM
GPT-4o	0.856	0.464	0.098
Claude-3.7	0.897	0.491	0.106
Qwen3-8B (SFT)	0.910	0.657	0.295
Qwen3-8B (SFT+RL)	0.904	0.659	0.319

Key finding: DAG EM collapses across all models on the Hard set—GPT-4o reaches only 0.098, whereas Qwen3-8B (SFT+RL) achieves 0.319—demonstrating that a specially trained small model substantially outperforms general-purpose large models.

StableToolBench End-to-End Execution

Method	Avg. SoPR	Avg. SoWR
GPT-3.5 (ReAct)	47.9	—
GPT-4 (ReAct)	48.2	58.7
GPT-4 (DFSDT)	70.3	64.2
ToolLLaMA (DFSDT)	54.2	47.1
LLMCompiler	36.2	37.9
Qwen3-8B (RL) + GPT-4o	59.8	55.0

Average inference steps: the proposed method requires only 2.29 steps, significantly fewer than DTA-Llama (2.48) and GPT-4 ReAct (3.27–4.23).

Ablation Study

• SFT → SFT+RL: DAG EM for Qwen3-8B improves from 0.781 → 0.803 on the Easy set and from 0.295 → 0.319 on the Hard set (+8.1% relative gain). RL primarily improves edge prediction (dependency modeling) rather than node selection (tool selection).
• Model scale effect: From Easy to Hard, the 1.7B model suffers a 71.2% accuracy drop (0.756 → 0.218), while the 8B model drops only 60.3% (0.803 → 0.319), indicating stronger robustness to complexity at larger scale.
• RL training instability at 0.6B: Insufficient model capacity leads to reward hacking—the model learns simple strategies to avoid penalties rather than genuinely solving tasks, revealing a minimum capacity requirement for stable RL training.
• SoPR vs. iterative methods: Iterative methods such as DTA-Llama achieve higher SoPR by leveraging multi-round error correction; the proposed single-pass planning paradigm is more efficient (fewest steps) but lacks a correction mechanism.

Highlights & Insights

• The DAG-as-plan formulation is intuitive and effective: decomposing complex tasks into tool nodes and dependency edges naturally supports parallel execution and is more expressive than linear chains.
• The reverse-engineering data construction pipeline is elegant: workflows are generated first, queries are back-synthesized, and re-planning serves as a quality filter—solving the bootstrapping problem of obtaining ground-truth planning data.
• The hierarchical reward function is well-designed: fail-fast evaluation, separation of structural vs. policy errors, and continuous F1 scoring provide rich gradient signals for RL.
• The Plan-Execute decoupled architecture allows the Planner and Executor to be upgraded independently, offering engineering flexibility.
• Filtering the RL training set using the SFT model draws on self-play principles, avoiding wasted training resources on trivially easy or intractably hard instances.

Limitations & Future Work

• No error correction in single-pass planning: The plan-then-execute paradigm offers no opportunity to revise a flawed plan, representing a core disadvantage compared to iterative methods (e.g., DTA-Llama, Reflexion). Real-world queries may be ambiguous, making the single-pass planning assumption overly strong.
• Hard set DAG EM remains low: Even the best model achieves only 0.319, indicating that complex planning is far from solved.
• Dependence on external Executor quality: End-to-end performance is highly sensitive to the Executor (GPT-4o), and the Planner's planning quality alone cannot guarantee end-to-end success.
• Dataset bias in ComplexTool-Plan: Training data generated by DeepSeek-V3 may inherit its planning preferences and blind spots, raising generalization concerns.
• Evaluation limited to StableToolBench: Despite being a mainstream benchmark, its API simulator and caching mechanism differ from real API environments.
• Absence of comparisons with recent Agent frameworks: e.g., AutoGen, CrewAI, and OpenAI's native function calling support.
• Potential improvement: introducing a lightweight re-planning mechanism (local re-planning upon tool call failure during execution) to balance efficiency and robustness.

Related Work & Insights

1. vs. ReAct: ReAct is a step-by-step reactive framework operating in a think-act-observe cycle. This paper argues that such incremental decision-making inherently leads to local optima, and that complex tasks require global planning. Experimentally, GPT-4 (ReAct) achieves only 48.2% SoPR, far below the proposed method's 59.8%.
2. vs. LLMCompiler: LLMCompiler also supports parallel tool invocation but performs localized parallelization within the ReAct framework. The fundamental distinction here is elevating planning to a dedicated stage with a specially trained model for global DAG generation.
3. vs. DTA-Llama / iterative methods: Iterative methods may achieve higher SoPR through multi-round execute-reflect-retry cycles. The proposed method is non-iterative, performing planning only once; its advantages are efficiency (fewest inference steps) and predictability, at the cost of lacking error correction.

Highlights & Insights (Transfer Value)

• The DAG planning + RL training paradigm is transferable to other domains requiring complex workflow orchestration (e.g., multimodal tasks, scientific experiment automation).
• The hierarchical reward design pattern (structural check → semantic check → quality scoring) applies to any RL setting requiring evaluation of structured outputs.
• The "forward generation + backward validation" data construction pipeline is reusable for other tasks requiring bootstrapped training data.
• A worthwhile open question: can a hybrid paradigm be designed—applying single-pass planning for simple subtasks while retaining reflection opportunities for uncertain ones?

Rating

• Novelty: ⭐⭐⭐⭐ The DAG planning + GRPO combination is novel, though plan-execute decoupling per se is not new (cf. PAL, PoT); the core contribution leans toward engineering implementation.
• Experimental Thoroughness: ⭐⭐⭐⭐ Covers both planning quality and end-to-end dimensions with detailed ablations; comparisons with recent Agent frameworks are missing, and Hard set results indicate the problem is far from solved.
• Writing Quality: ⭐⭐⭐⭐ Clear structure, precise problem formulation, and well-designed figures; the Related Work section is citation-dense, slightly reducing readability.
• Value: ⭐⭐⭐⭐ Provides practical guidance for Agent planning research; the data construction pipeline and hierarchical reward design are reusable; practical value is somewhat reduced by the single-pass planning limitation.

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