What it does

Agent Replay plays back a code change line by line. The agent's recorded explanation appears alongside the change. With Node 20+ and git installed, running npx agent-replay-studio@latest from a repository opens a local player. The player finds existing Claude Code, Codex, and Gemini CLI logs. The reader picks a project and a session. If the project is missing, Open folder… in the project picker points it at the repository. A supported session log or a saved replay is still required. Space plays or pauses. The right arrow finishes the current animation or advances one step. The left arrow goes back. N jumps between review notes. The file tree shows where each edit belongs. Switching to File shows the surrounding function.

Capabilities

The Evidence panel lists recorded test runs and other recognized checks with their results. It also flags deleted tests, failures hidden by shell pipes, and edits after a passing check.
The Evidence panel reads recorded commands and output. It does not rerun tests or prove correctness.
The history command replays Git history commit by commit. The --from option chooses a starting revision, including the first commit. Adding --learn introduces the files already present at that starting point. Without --from, history shows up to the latest 300 commits.
For Claude Code, npx agent-replay-studio@latest skills install installs teaching skills from the repository. The agent can then build concise tutorials for the current repository, which open under Learn.
A replay can be exported as a self-contained HTML file that opens offline. The export contains code and session context.

When to use it

Reviewing a sizeable pull request that arrives as a wall of changes.
Giving the next reviewer a way to follow the same steps alongside a pull request.
Learning a repository you are about to own.