Agentic Patterns: ReAct vs. Plan-and-Solve

Not all Agents think alike. The “cognitive architecture”—the loop that drives the agent—determines its capability.

1. ReAct (Reason + Act)

Visualized: Thought -> Action -> Observation -> Thought...

The agent takes one step, looks at the result, and then decides the next step.

• Pros: Highly adaptive. If step 1 fails, it notices immediately.
• Cons: Can get stuck in loops. “Tunnel vision” prevents it from seeing the bigger picture.
• Best For: Web browsing, debugging, open-ended research.

2. Plan-and-Solve (BabyAGI style)

Visualized: Plan (Step 1, 2, 3) -> Execute 1 -> Execute 2 -> Execute 3

The agent creates a full manifest upfront and then executes it blindly or semi-blindly.

• Pros: Efficient. Stays on track. Great for long-horizon tasks.
• Cons: Fragile. If Step 1 output changes the requirements for Step 3, the plan fails.
• Best For: Code generation, writing articles, defined workflows.

The Hybrid Approach

The state-of-the-art in 2026 is Dynamic Planning. The agent creates a plan, executes Step 1, and then re-evaluates the plan based on the observation. It combines the structure of Plan-and-Solve with the adaptability of ReAct.