I was digging through Claude Code session transcripts and realized something: every file change is already being recorded. Every edit, every version, every diff. It was all sitting there in the JSONL session data, just buried in a format nobody wants to read.

So I built File History into Poirot.

What It Does

If your session changes a file or several of them, you can now check exactly what changed and see multiple versions inside the session. Every edit, right there in the timeline.

You can:

• See all files modified during a session in a sidebar
• Compare any two versions of a file with inline diffs
• Save the changes as a patch file
• Export the diff as an image
• Copy it to your clipboard

Why This Matters

I wrote about cognitive debt recently. The idea that we ship AI-generated code without understanding it, that the theory stays in the prompt instead of our heads.

File History is one answer to that. Instead of guessing what the agent changed, you can see every step it took. Every version, every decision point. It does not replace understanding, but it makes reviewing what happened much faster.

The Data Was Always There

Claude Code records everything in its session transcripts. File reads, writes, diffs, tool calls. The problem was never missing data. It was that the data lived in raw JSONL files that nobody wants to scroll through.

Poirot just gives it a window.

Open source, native macOS, under 6 MB, fully offline. brew install --cask poirot

GitHub: github.com/leonardocardoso/poirot