AgentSearch: Learning Efficient Agentic Workflows via Deliver Tree Search
: Multi-Agent systems powered by Large Language Models have demonstrated remarkable capabilities; however, their effectiveness is limited by rigid, manually designed workflows that do not adapt to varying task complexity. Existing adaptive methods utilize greedy policies that select workflow components without antic-ipating downstream cost-accuracy tradeoffs, often necessitating multiple attempts to identify successful configurations. This work introduces AgentSearch, a cost-aware Monte Carlo Tree Search (MCTS) framework that constructs agentic workflows through deliberative lookahead search. The proposed approach employs a dual-network architecture: a value network that decomposes expected rewards into success probability and remaining cost estimates, and a grammar-constrained policy network that ensures semantically valid constructions. Guided by these networks, MCTS explicitly simulates candidate workflow trajectories, enabling principled reasoning about the cost-accuracy tradeoff prior to decision-making. The networks are trained using a multi-phase protocol that combines stochastic exploration, supervised pre-training, and self-play refinement. Experiments on mathematical reasoning (MATH, AQUA-RAT) and code generation (HumanEval, MBPP) benchmarks demonstrate that the method achieves 80.03% average accuracy, surpassing Chain-of-Thought by 13.78 points and the best multi-agent baseline by 8.87 points. Notably, the approach attains single-episode success while reducing computational costs by up to 47%, thereby eliminating the trial-and-error exploration required by previous adaptive methods.