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How to build a Frontend for LangChain Deep Agents with CopilotKit!

Anmol Baranwal on January 20, 2026

LangChain recently introduced Deep Agents: a new way to build structured, multi-agent systems that can plan, delegate, and reason across multiple s...
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Cyber Safety Zone

Thanks for this walkthrough! The step-by-step breakdown of building a frontend for LangChain Deep Agents with CopilotKit was super clear and practical. I especially appreciated the way you tied UI components to the agent’s logic — that makes it much easier to follow. Great job! 👏💡

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uliyahoo CopilotKit

Great Job Anmol!

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Anmol Baranwal CopilotKit

Thanks Uli. I'm sure people will build crazy stuff using Deep Agents :)

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Bonnie CopilotKit

Well written article, Anmal!

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Anmol Baranwal CopilotKit

Thanks Bonnie! UI is a bit messy lol (most of the time went in improving system prompt) but hopefully others build something cool with this pattern.

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Bonnie CopilotKit

Good to see you back creating great articles.

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PEACEBINFLOW

This is the part of agent dev people keep skipping: the frontend. Building the agent is the easy flex — getting state, tools, and outputs to flow cleanly into a UI without dumping JSON into chat is where it gets real.

I like how you framed Deep Agents as “plan → delegate → externalize context” instead of the usual “LLM in a loop and pray.” And the CopilotKit + AG-UI sync makes a lot of sense because the agent’s state is already explicit (todos, files, messages). That’s the missing bridge.

Also: the strict prompt rule of “jobs only via update_jobs_list” is such a simple move but it solves a huge UX problem. Keeping chat conversational while structured data renders separately is the difference between a demo and a product.

Good write-up — this actually makes Deep Agents feel buildable, not just blog-hype.

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Anmol Baranwal CopilotKit • Edited

yeah, I went through like 10+ different system prompts (it got a bit crazy 😅) and this was the one that finally worked after a lot of refinement. In the end, Deep Agents have a really powerful architecture pattern & using CopilotKit gives you a lot more visibility into what’s actually happening.

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Nathan Tarbert CopilotKit

Great walkthrough, Anmol!

I've been waiting for a tutorial on Deep Agents, this is great!

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Anmol Baranwal CopilotKit

Thanks Nathan. the concepts of subagents is really cool and the entire architecture of deep agents is actually impressive -- I'm definitely going to go really deep in their docs and try more stuff.

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Fliin

Nice writeup!
This really helped my understanding of how and when I can use a Deep Agent

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Sayeed

Love the detail here

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Eli Berman CopilotKit

This is awesome Anmol! I know a lot of people who have been struggling to build frontend capabilities for their deep agents. This makes it way easier

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Anmol Baranwal CopilotKit

yeah deep agents provides some really cool stuff built-in and I learned a lot while building this.

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Zender

Very helpful. Great detail and I have a better understanding of which pieces fit where. Thanks

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ANIRUDDHA ADAK

Well explained