# Harrison Chase highlights three lessons from Hex 4.0 for building agents

> Original title: the hex team consistently gets what it means to build agents, and software to support them

- Source: Harrison Chase
- Published: 2026-10-27T19:20:41.000Z
- Bad Influence: https://badinfluence.news/items/ttgbmn4en9lqbuszrgfn9xan1
- Original: https://x.com/hwchase17/status/2115161782079897946

## Summary

Harrison Chase says Hex 4.0 mirrors three approaches LangChain has taken: using code as the backbone, designing UI for reviewing agent work, and rebuilding core infrastructure for speed. He argues these three points apply to any company building agents. Hex 4.0 is described as the first analytics platform built for agents, announced alongside a $100M fundraise at a $1.2B valuation.

## Post

the hex team consistently gets what it means to build agents, and software to support them

three things that caught my eye from Hex 4.0 that mirror what we've done at LangChain and that I think speak to the future of building agents

1/ use code as a backbone. they moved from yaml to more flexible code. agents are really good at writing code, and people want lots of flexibility in UI, so i think we will see more teams have parts of their UI that are powered by code. We did this in LangSmith with Custom Apps (completely custom UI)

2/ UX focused on reviewing. "A new, intuitive Hex UI, built for reviewing and understanding". As agents do more work, the bottleneck becomes reviewing work. We did a similar thing in LangSmith with our new Trajectory view, focused on being a new view over agent trajectories that make it easy to review

3/ rebuilt core infra. "An all-new, ridiculously faster execution engine". agents will still use infra/software. and it will need to be faster/better to accomodate more usage. We did this in LangSmith with SmithDB, our custom database for agent traces

I think all these three things (lets agents write custom UIs as code, invest in UI/UX that make it easier to review, make your core infra more scalable) are all generalizable to any company building agents

congrats to Hex team on a great milestone and great launch!

## Quoted post @barrald

> In May, we had just closed our best quarter ever – and of course decided to re-build @hexanalytics from scratch.
> 
> Today we're announcing two things: Hex 4.0, the first analytics platform truly built for agents; and a $100m fundraise at a $1.2B valuation, led by @peakxvpartners 
> 
> The world is changing fast, and we're not slowing down! Read more here:
> 
> https://hex.tech/blog/hex-new-era/

https://x.com/barrald/status/2115095682004726173