Agentic AI Reference Architecture

Cognition · Software component

Hybrid Breadth-then-Depth Thought Search Controller

Software componentCognitionCognition & Memoryarc:HybridBreadthDepthThoughtSearchController

A tree search controller that explores diverse alternatives breadth-first at shallow depths, then switches to depth-first exploration of the most promising branches.

Responsibility. Switches from breadth-first hedging to depth-first commitment as depth increases.

Also known as: BFS-then-DFS search, Limited-backtracking search with backup branches

Variant of Tree Search Controller abstract

When to choose. Choose when robustness against early misevaluation at shallow depths and efficient deep exploration are both needed and extra implementation complexity is acceptable.

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Direct neighbourhood (hover for relationship types)

Relationships

alternative to variability

Design guidance

Classification

Patterns
Hybrid BFS/DFS search
Quality attributes
Reliability (ISO/IEC 25010 | NIST AI RMF: valid and reliable)Performance efficiency (ISO/IEC 25010)

Sources

  1. Ch5.2: T. Nguyen, "Tree-of-Thought (ToT) Fundamentals," in Mastering Agentic AI Systems: Guide for the NVIDIA NCP-AAI Exam, 1st ed. 2026, ch. 5.2. ISBN: 9798244538229.