Cline v3.39: Explain Changes Cuts Code Review Friction

TL;DR

• Cline v3.39 adds Explain Changes: inline explanations for AI-generated diffs before you commit
• Comments appear directly in the diff view with reasoning context, not in a separate chat
• /explain-changes slash command works on any git diff—commits, branches, PRs, staged changes

What Dropped

Cline v3.39 introduces Explain Changes, a feature that streams inline explanations directly into your diff view after Cline completes a task. Instead of switching between diffs and chat to understand what changed, you get comments placed exactly where the changes are, with full conversation context baked in.

The feature also ships a /explain-changes slash command that works on any git diff independently—commits, branches, PRs, staged changes, or your working directory.

The Dev Angle

The problem is real: developers spend 58-70% of their time on program comprehension, not writing code. When Cline generates 15-file changes in seconds, the review burden explodes. Traditional diffs force context switching between code and explanations, which cognitive science shows is exhausting. The result? Developers rubber-stamp PRs without substantive review.

Explain Changes eliminates that friction. Explanations appear inline with the code, so you understand both what changed and why without leaving the diff view. Each comment has a reply thread for follow-ups like "Why this approach instead of X?" Cline responds with context-aware answers. If a thread gets complex, click the title to move it into the main chat for full Cline capabilities.

The /explain-changes command is broader: use it to understand your teammate's last commit, review a PR before approving, investigate production bugs, or catch up on a codebase you haven't touched in weeks. It works on any git reference—no Cline task required.

Should You Care?

If you're using Cline to generate multi-file changes, this is essential. You're responsible for what ships, and understanding AI-generated code before committing is non-negotiable. Explain Changes makes that actually feasible instead of a cognitive slog.

If you're not using Cline yet but do code reviews, the /explain-changes command alone is worth trying. It's a faster way to onboard to unfamiliar code or understand what broke in production.

The feature requires Checkpoints to be enabled for the button-triggered workflow. The slash command works independently with just git.

Source: Cline