README.md

GraphAgent Basic Example — Conditional Routing

This example demonstrates a data validation pipeline using conditional routing based on runtime state. The validator checks input quality and branches to either a processor (success path) or an error handler (failure path), showing how GraphAgent enables state-dependent decision logic that sequential or parallel agent composition alone cannot achieve.

When to Use This Pattern

• Any workflow requiring "if X then A, else B" branching on agent output
• Input validation before expensive downstream processing
• Quality-gate patterns where the next step depends on a score or classification

How to Run

adk run contributing/samples/graph_agent_basic

Graph Structure

validate ──(valid=True)──▶ process
         ──(valid=False)─▶ error

Key Code Walkthrough

• GraphNode(name="validate", agent=validator_agent) — wraps an LlmAgent as a graph node
• add_edge("validate", "process", condition=lambda s: s.data["valid"] == True) — conditional edge that only fires when the validation flag is set
• Two end nodes (process and error) — GraphAgent can have multiple terminal nodes
• State propagation — each node's output is written to state.data[node_name] and read by downstream condition functions
• No cycles — this is a simple directed acyclic graph; for loops see graph_agent_dynamic_queue