Show HN: Libretto – Making AI browser automations deterministic • Hacker News Board

z3ugma wrote: post #14

Love it! Do you have a BAA with Claude though? Otherwise, your demo is likely exposing PHI to 3rd parties and exposing you to risk related to HIPAA

just adding to michael's reply - we took care to make sure no PHI was exposed in our demo video as well.

Re: Show HN: Libretto – Making AI browser automations deterministic

#36

Post by tanishqkanc » Thu, Apr 16, 2026, 3:28 AM UTC

yehia2amer wrote: post #33

how does it differ from https://github.com/browserbase/stagehand ?

we started using stagehand initially! But it doesn't follow the same model of pre-generating deterministic code. Your code is meant to look like this:

// Let AI click await stagehand.act("click on the comments link for the top story");

the issue with this is that there's now runtime non-determinism. We move the AI work during dev-time: AI explores and crawls the website first, and generates a deterministic legible script.

Tangentially, Stagehand's model may have worked 2 years ago when humans still wrote the code, but it's no longer the case. We want to empower agents to do the heavy lifting of building a browser automation for us but reap the benefits of running deterministic, fast, cheap, straightforward code.

Re: Show HN: Libretto – Making AI browser automations deterministic

#37

Post by tanishqkanc » Thu, Apr 16, 2026, 3:41 AM UTC

messh wrote: post #3

how does it differ from playwright-cli?

playwright-cli is very simple and meant for humans - it basically generates a first draft of a script, and was originally meant for writing e2e tests. You need to do a lot of post-processing on it to get it to be a reliable automation.

libretto gives a similar ability for agents for building scripts but:

- agents automatically run, debug, and test the integrations they write - they have a much better understanding of the semantics of the actions you take (vs. playwright auto-assuming based on where you clicked) - they can parse network requests and use those to make direct API calls instead

there's fundamentally a mismatch where playwright-cli is for building e2e test scripts for your own app but libretto is for building robust web automations

Re: Show HN: Libretto – Making AI browser automations deterministic

#38

Post by tanishqkanc » Thu, Apr 16, 2026, 3:41 AM UTC

seagull wrote: post #4

I've wanted something like this for ages, excited to try this out!

glad to hear! Please reach out on Discord or Github issues you run into issues!

Re: Show HN: Libretto – Making AI browser automations deterministic

#39

Post by tanishqkanc » Thu, Apr 16, 2026, 3:44 AM UTC

daveguy wrote: post #13

What is the license? Edit: nevermind. I see from the website it is MIT. Probably should add a COPYING.md or LICENSE.md to the repository itself.

Sorry! Yes, MIT. Forgot to lift it up when I converted to a monorepo, but it's in packages/libretto

Re: Show HN: Libretto – Making AI browser automations deterministic

#40

Post by tanishqkanc » Thu, Apr 16, 2026, 3:44 AM UTC

gbibas wrote: post #7

Cool. Thank you for sharing. While AI tools are extremely powerful, packages like this help create some good standards and stepping stones for connectivity that the models haven’t gotten around to yet. Thanks again.

Ofc! Please try it out. Stop by in the Discord or Github Issues if you have any questions!