Hey,

Today we’re excited to introduce the first dev tool that wraps the verification methodology we’ve been developing: lemmafit streamlines verification of logic with a simple npm install.

As a reminder: our long-term vision is that humans only define what should be built, AI handles implementation, and machines guarantee correctness. lemmafit is the first step toward this vision.

The flow:

1. Claude makes a plan that includes logic.

2. lemmafit intercepts and instructs Claude to write the logic in verification-aware language.

3. lemmafit guides Claude through full verification process: proofs, audits, iteration, guarantees.

4. Claude is given a Typescript API to hook into the UI. No logic is duplicated in the UI layer.

5. You get certain guarantees about your code: “Shopping cart quantity can never be negative”

This is version 0.1.0. It’s a working version, but it’s limited to greenfield projects and Claude Code. There’s a lot more work to be done. What’s next:

- Adding integration with existing codebases to: 1) gradually verify existing code, and 2) model the codebase to find bugs that tests didn’t catch
- Expanding agent coverage (targeting agent-agnostic)

…and more.

As always, we are open to feedback and collabs!

Til the next release,
Fernanda

PS: We’re pushing harder on visibility. We updated our website, started a Bluesky account, and will be posting regular updates on LinkedIn. We’d love a follow and a share.

Github | LinkedIn | Bluesky