Reviewing the agent's changes

Mel shows you every change the agent makes three times: as a diff on the approval card before it's written, as a diff card in the conversation after it's written, and in the code review panel, where you can accept, undo, stage and commit it.

Before: the approval card

When the agent wants to write or edit a file, the approval card shows the unified diff of exactly what will be written: the same text the write will use, not a summary. Read it and choose:

• Allow edit for this one change;
• Always allow file edits in this conversation, to stop being asked for edits until the conversation ends;
• Deny (or Esc), and the agent is told and changes course.

Allow doesn't react for a moment after the card appears, so a key you were already pressing can't approve it. See Tools & approvals.

After: diff cards in the conversation

Every applied edit leaves a diff card: the file path, +N and -N counts, and the changed lines in red and green. The turn's usage line totals the files changed and lines applied.

If an edit leaves a file that no longer parses (for example a JSON file with a trailing comma), Mel adds a line saying so under the result, and the agent sees it too.

The code review panel

Click ± Review changes under a turn that edited files, press Ctrl+Shift+= (⌘⇧= on a Mac), or run Open Code Review from the command palette. The panel opens beside the conversation and shows the project's diff, one card per file.

• Accept stages one change, and Undo takes one change back out of your files.
• Approve stages every file shown.
• Attach diff puts the diff in the agent's message box, so you can ask about it.
• Commit: type a message and click Commit N files.
• ↩ Discard reverts one file, and ↩ Discard all reverts every tracked change after you confirm.
• Hover a line and click 💬 to leave a comment, then send your comments to the agent to fix. See Diffs & comments.

To open the panel by itself on a conversation's first change, turn on Auto open code review panel in Settings ▸ Editor and Code Review. More in Code review panel.

A good review loop

1. Let the agent finish the task.
2. Open the review panel and read each file.
3. Comment on what's wrong and send the comments to the agent.
4. When it's right, Approve and Commit.

Limitations

• The review panel needs a git repository. Outside one, you still get the approval card and the diff cards.
• The panel shows at most 40 files and 400 lines per file. Use git diff in the terminal for more.

FAQ

Can I undo everything the agent did? In a git repository, ↩ Discard all reverts tracked changes. Files the agent created are untracked; discard them one by one from their cards.

Does the VS Code extension show diffs too? Yes. Each changed file gets a card, and Open diff opens VS Code's diff editor. See VS Code extension.