Inline diff rewrite.

Select text in any note, trigger a rewrite, and review the AI's changes line-by-line before they land. Green for additions, red for deletions, plain for unchanged. Accept to apply, reject to discard.

What it is

Replace-mode selection actions never write silently — every result opens in the diff modal first (SELECTION_ACTIONS.md). The dedicated diff rewrite is that same review flow running the built-in "improve writing" prompt: it shows the original and rewritten versions as a diff, and only writes to the note if you click Accept.

This is the right tool when you want to keep tight control over edits — when the original wording matters, when the AI might over-rewrite, or when you're reviewing substantial changes.

How to invoke

Three entry points for the improve rewrite:

Method	How
Hotkey	Assignable under Settings → Hotkeys → "Curtis.ai: Rewrite selection with AI (with diff)" (no default, to avoid conflicts)
Context menu	Right-click a selection → Rewrite with AI (diff)
Command palette	Ctrl+P → "Curtis.ai: Rewrite selection with AI (with diff)"

Other replace-mode actions (summarize, fix grammar, custom actions, …) land in the same modal — trigger them their usual way. Everything uses your currently active model and provider — whatever's selected in the chat header.

Workflow

1. Select the text you want to rewrite in any note
2. Trigger the rewrite via any of the three methods above
3. The AI generates a result (the improve prompt here, the action's own prompts elsewhere)
4. The diff modal opens, showing line-by-line changes:
   • + green lines — additions
   • - red lines — deletions
   • (space) plain lines — unchanged
5. Review the diff
6. Click Accept to replace the selection with the rewritten text, or Reject to close the modal without changes

Custom prompts

The rewrite entry itself uses a built-in prompt tuned for "improve clarity, fix grammar, preserve meaning." For your own prompts, define a custom selection action with insert mode replace — it gets the same diff review.

Diff algorithm

Line-level diff via longest-common-subsequence (LCS) dynamic programming. O(n*m) time and space, which is fast enough for typical AI rewrite sizes (under ~200 lines).

For very large selections, the diff still works but may take a moment to compute. The modal stays responsive during computation.

Future work

Still on the roadmap:

• Word-level diff — currently diff is line-granular. A word-level mode would show intra-line changes (like GitHub's split diff).
• Inline editor decorations — show the diff directly in the editor (like Cursor or GitLens inline blame) instead of a modal. Faster review loop for small changes.
• Multi-turn refinement — "make it more concise" without re-selecting
• Partial accept — accept some hunks, reject others