diff --git a/CHANGELOG.md b/CHANGELOG.md
index 49902a8..1e4bb0b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,43 @@
 
 All notable changes to Switchboard Core are documented here.
 
+## v0.4.0 — Notes Surface
+
+### Added
+
+- **Notes surface package** (`packages/notes/`): Obsidian-style markdown notes
+  rebuilt as a standard installable `.pkg` archive. Type `full`, tier `starlark`.
+  Zero kernel changes — proves the extension stack end-to-end.
+- **Starlark backend** (`script.star`): 7 API routes — CRUD, search, stats.
+  Note bodies stored in `ext_notes_notes` TEXT columns. List endpoint returns
+  lightweight projections (no body); full content fetched on select.
+- **Markdown editor**: Preact+htm frontend with sidebar note list, monospace
+  textarea, and toggle-able live preview. Inline markdown renderer (~100 lines)
+  covers headings, bold, italic, code blocks, links, lists, blockquotes, and HR.
+- **Auto-save**: Debounced save (1s) with dirty/saved status indicator.
+  `Ctrl/Cmd+S` for force save. Tab key inserts two spaces.
+- **Pin & archive**: Pin important notes to the top of the list. Archive
+  (soft-delete) via the delete button; hard delete with `?hard=1` query param.
+- **Search**: Case-insensitive full-text search across title and body content.
+  Search bar in sidebar filters the note list in real-time.
+- **Theme support**: All styles use CSS variables — light and dark themes work
+  out of the box. Responsive layout collapses to vertical on narrow viewports.
+
+### Data model
+
+| Table | Columns |
+|-------|---------|
+| `ext_notes_notes` | title, body, folder_id, creator_id, updated_at, pinned, archived |
+
+Indexes on `folder_id`, `creator_id`, `pinned`, `updated_at`.
+
+### Planned (v0.4.1–v0.4.4)
+
+- Folders + navigation tree
+- Tags + enhanced search
+- Backlinks + `[[wikilinks]]`
+- Rich editor (CodeMirror 6) + markdown import/export
+
 ## v0.3.8 — Distribution
 
 ### Added
diff --git a/VERSION b/VERSION
index 6678432..1d0ba9e 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.3.8
+0.4.0