Prev Next

AI / LangGraph LangChain Interview questions

How do agents plan and reason?

LangChain agents use the ReAct (Reasoning + Acting) framework to plan and reason. The model is prompted to produce interleaved Thought, Action, and Observation sequences. The Thought is the model's explicit reasoning about what to do next; the Action is the tool call decision; the Observation is the tool's returned result. This cycle repeats until the model produces a "Final Answer".

A ReAct trace looks like this:

Question: Who is the CEO of Anthropic and when was the company founded?

Thought: I need to search for information about Anthropic.
Action: search
Action Input: "Anthropic CEO founder"
Observation: Anthropic was founded in 2021. Dario Amodei is the CEO.

Thought: I now have both pieces of information needed to answer.
Final Answer: Anthropic's CEO is Dario Amodei. The company was founded in 2021.

For models with native function calling (OpenAI, Anthropic), the reasoning is more structured: the model returns a JSON tool call object rather than parsing free text, which is more reliable. The OpenAI Tools Agent uses this approach. Newer techniques like chain-of-thought prompting and tree-of-thought can be integrated to improve multi-step reasoning quality by providing examples of good reasoning chains in the system prompt.

In the ReAct framework, what is the 'Thought' step?
Why is the OpenAI Tools Agent more reliable than a text-based ReAct Agent?

More Related questions...

What is LangChain? What is LCEL (LangChain Expression Language)? What are the key components of LangChain? How does LangChain differ from traditional LLM integration? What are LangChain Runnables? How do you install and set up LangChain? How do you use ChatModels in LangChain? What are PromptTemplates in LangChain? What are output parsers in LangChain? What is the LangSmith platform? What is LangChain Hub? What is LangServe? How do callbacks work in LangChain? How do you implement streaming in LangChain? How does LangChain handle versioning? What are Chains in LangChain? What is the difference between sequential and parallel chains? How do you use the pipe operator in LCEL? What are RunnablePassthrough and RunnableLambda? What are common chain composition patterns? How do you implement a ConversationChain? How does routing work in LCEL? How do you handle errors in chains? What are chain fallbacks and retries? How do you do batch processing with LCEL? What are LangChain Agents? What are the different agent types in LangChain? How do you create custom agents? What is AgentExecutor? How do tools work in LangChain agents? How do you create custom tools? What are multi-action agents? How do agents plan and reason? How do you integrate memory with agents? How do you debug LangChain agents? What is LangGraph? What are the differences between LangGraph and LangChain Agents? What is StateGraph in LangGraph? How do nodes and edges work in LangGraph? How do you implement conditional edges in LangGraph? How does state management work in LangGraph? What is the difference between MessageGraph and StateGraph? How does checkpointing work in LangGraph? How do you implement human-in-the-loop with LangGraph? How do you build multi-agent systems with LangGraph? What are subgraphs in LangGraph? How do streaming and callbacks work in LangGraph? What are persistence patterns in LangGraph? How do you handle errors in LangGraph? How do you deploy LangGraph applications?
Show more question and Answers...

Prompt Engineering Interview questions

Comments & Discussions

Interviews Questions

About Javapedia.net

Javapedia.net is for Java and J2EE developers, technologist and college students who prepare of interview. Also this site includes many practical examples.

This site is developed using J2EE technologies by Steve Antony, a senior Developer/lead at one of the logistics based company.

Follow Javapedia updates

contact: javatutorials2016[at]gmail[dot]com

Kindly consider donating for maintaining this website. Thanks.

Copyright © 2026, javapedia.net, all rights reserved. · .

DMCA.com Protection Status