phcode-dev · abose · Feb 20, 2026 · Feb 19, 2026
diff --git a/CLAUDE.md b/CLAUDE.md
@@ -12,3 +12,15 @@
 - Always use curly braces for `if`/`else`/`for`/`while`.
 - No trailing whitespace.
 - Use `const` and `let` instead of `var`.
+
+## Phoenix MCP (Desktop App Testing)
+
+Use `exec_js` to run JS in the Phoenix browser runtime. jQuery `$()` is global. `brackets.test.*` exposes internal modules (DocumentManager, CommandManager, ProjectManager, FileSystem, EditorManager). Always `return` a value from `exec_js` to see results. Prefer reusing an already-running Phoenix instance (`get_phoenix_status`) over launching a new one.
+
+**Open AI sidebar tab:** `document.querySelectorAll('span').forEach(s => { if (s.textContent.trim() === 'AI' && s.childNodes.length === 1) s.parentElement.click(); });`
+
+**Send AI chat message:** `$('.ai-chat-textarea').val('prompt'); $('.ai-chat-textarea').trigger('input'); $('.ai-send-btn').click();`
+
+**Click AI chat buttons:** `$('.ai-edit-restore-btn:contains("Undo")').click();`
+
+**Check logs:** `get_browser_console_logs` with `filter` regex (e.g. `"AI UI"`, `"error"`) and `tail` — includes both browser console and Node.js (PhNode) logs. Use `get_terminal_logs` for Electron process output (only available if Phoenix was launched via `start_phoenix`).
diff --git a/src/core-ai/AIChatPanel.js b/src/core-ai/AIChatPanel.js
@@ -42,6 +42,7 @@ define(function (require, exports, module) {
     const _previousContentMap = {}; // filePath → previous content before edit, for undo support
     let _currentEdits = [];          // edits in current response, for summary card
     let _firstEditInResponse = true; // tracks first edit per response for initial PUC
+    let _undoApplied = false;        // whether undo/restore has been clicked on any card
     // --- AI event trace logging (compact, non-flooding) ---
     let _traceTextChunks = 0;
     let _traceToolStreamCounts = {}; // toolId → count
@@ -292,6 +293,7 @@ define(function (require, exports, module) {
         _hasReceivedContent = false;
         _isStreaming = false;
         _firstEditInResponse = true;
+        _undoApplied = false;
         SnapshotStore.reset();
         Object.keys(_previousContentMap).forEach(function (key) {
             delete _previousContentMap[key];
@@ -493,15 +495,16 @@ define(function (require, exports, module) {
             linesRemoved: oldLines
         });
 
-        // Capture pre-edit content into pending snapshot and back-fill
+        // Capture pre-edit content for snapshot tracking
         const previousContent = _previousContentMap[edit.file];
         const isNewFile = (edit.oldText === null && (previousContent === undefined || previousContent === ""));
-        SnapshotStore.recordFileBeforeEdit(edit.file, previousContent, isNewFile);
 
-        // On first edit per response, insert initial PUC if needed
+        // On first edit per response, insert initial PUC if needed.
+        // Create initial snapshot *before* recordFileBeforeEdit so it pushes
+        // an empty {} that recordFileBeforeEdit will back-fill directly.
         if (_firstEditInResponse) {
             _firstEditInResponse = false;
-            if (!SnapshotStore.isInitialSnapshotCreated()) {
+            if (SnapshotStore.getSnapshotCount() === 0) {
                 const initialIndex = SnapshotStore.createInitialSnapshot();
                 // Insert initial restore point PUC before the current tool indicator
                 const $puc = $(
@@ -525,6 +528,9 @@ define(function (require, exports, module) {
             }
         }
 
+        // Record pre-edit content into pending snapshot and back-fill
+        SnapshotStore.recordFileBeforeEdit(edit.file, previousContent, isNewFile);
+
         // Find the oldest Edit/Write tool indicator for this file that doesn't
         // already have edit actions. This is more robust than matching by toolId
         // because the SDK with includePartialMessages may re-emit tool_use blocks
@@ -601,6 +607,7 @@ define(function (require, exports, module) {
     function _appendEditSummary() {
         // Finalize snapshot and get the after-snapshot index
         const afterIndex = SnapshotStore.finalizeResponse();
+        _undoApplied = false;
 
         // Aggregate per-file stats
         const fileStats = {};
@@ -630,7 +637,7 @@ define(function (require, exports, module) {
                 .attr("title", "Restore files to this point");
 
             // Determine button label: "Undo" if not undone, else "Restore to this point"
-            const isUndo = !SnapshotStore.isUndoApplied();
+            const isUndo = !_undoApplied;
             const label = isUndo ? "Undo" : "Restore to this point";
             const title = isUndo ? "Undo changes from this response" : "Restore files to this point";
 
@@ -687,7 +694,7 @@ define(function (require, exports, module) {
         $msgs.find(".ai-restore-highlighted").removeClass("ai-restore-highlighted");
 
         // Once any "Restore to this point" is clicked, undo is no longer applicable
-        SnapshotStore.setUndoApplied(true);
+        _undoApplied = true;
 
         // Reset all buttons to "Restore to this point"
         $msgs.find('.ai-edit-restore-btn').each(function () {
@@ -718,7 +725,7 @@ define(function (require, exports, module) {
      */
     function _onUndoClick(afterIndex) {
         const $msgs = _$msgs();
-        SnapshotStore.setUndoApplied(true);
+        _undoApplied = true;
         const targetIndex = afterIndex - 1;
 
         // Reset all buttons to "Restore to this point"

diff --git a/src/core-ai/AISnapshotStore.js b/src/core-ai/AISnapshotStore.js
@@ -33,10 +33,7 @@ define(function (require, exports, module) {
     // --- Private state ---
     const _contentStore = {};        // hash → content string (content-addressable dedup)
     let _snapshots = [];             // flat: _snapshots[i] = { filePath: hash|null }
-    let _lastSnapshotAfter = {};     // cumulative state after last completed response
     let _pendingBeforeSnap = {};     // built during current response: filePath → hash|null
-    let _initialSnapshotCreated = false;  // has the initial (pre-AI) snapshot been pushed?
-    let _undoApplied = false;
 
     // --- Path utility ---
 
@@ -226,10 +223,6 @@ define(function (require, exports, module) {
                     snap[filePath] = hash;
                 }
             });
-            // Also back-fill _lastSnapshotAfter
-            if (_lastSnapshotAfter[filePath] === undefined) {
-                _lastSnapshotAfter[filePath] = hash;
-            }
         }
     }
 
@@ -239,19 +232,10 @@ define(function (require, exports, module) {
      * @return {number} the snapshot index (always 0)
      */
     function createInitialSnapshot() {
-        const snap = Object.assign({}, _lastSnapshotAfter);
-        _snapshots.push(snap);
-        _initialSnapshotCreated = true;
+        _snapshots.push({});
         return 0;
     }
 
-    /**
-     * @return {boolean} whether the initial snapshot has been created this session
-     */
-    function isInitialSnapshotCreated() {
-        return _initialSnapshotCreated;
-    }
-
     /**
      * Finalize snapshot state when a response completes.
      * Builds an "after" snapshot from current document content for edited files,
@@ -261,8 +245,8 @@ define(function (require, exports, module) {
     function finalizeResponse() {
         let afterIndex = -1;
         if (Object.keys(_pendingBeforeSnap).length > 0) {
-            // Build "after" snapshot = current _lastSnapshotAfter + current content of edited files
-            const afterSnap = Object.assign({}, _lastSnapshotAfter);
+            // Build "after" snapshot = last snapshot + current content of edited files
+            const afterSnap = Object.assign({}, _snapshots[_snapshots.length - 1]);
             Object.keys(_pendingBeforeSnap).forEach(function (fp) {
                 const vfsPath = realToVfsPath(fp);
                 const openDoc = DocumentManager.getOpenDocumentForPath(vfsPath);
@@ -271,11 +255,9 @@ define(function (require, exports, module) {
                 }
             });
             _snapshots.push(afterSnap);
-            _lastSnapshotAfter = afterSnap;
             afterIndex = _snapshots.length - 1;
         }
         _pendingBeforeSnap = {};
-        _undoApplied = false;
         return afterIndex;
     }
 
@@ -294,20 +276,6 @@ define(function (require, exports, module) {
         });
     }
 
-    /**
-     * @return {boolean} whether undo has been applied (latest summary clicked)
-     */
-    function isUndoApplied() {
-        return _undoApplied;
-    }
-
-    /**
-     * @param {boolean} val
-     */
-    function setUndoApplied(val) {
-        _undoApplied = val;
-    }
-
     /**
      * @return {number} number of snapshots
      */
@@ -321,22 +289,16 @@ define(function (require, exports, module) {
     function reset() {
         Object.keys(_contentStore).forEach(function (k) { delete _contentStore[k]; });
         _snapshots = [];
-        _lastSnapshotAfter = {};
         _pendingBeforeSnap = {};
-        _initialSnapshotCreated = false;
-        _undoApplied = false;
     }
 
     exports.realToVfsPath = realToVfsPath;
     exports.saveDocToDisk = saveDocToDisk;
     exports.storeContent = storeContent;
     exports.recordFileBeforeEdit = recordFileBeforeEdit;
     exports.createInitialSnapshot = createInitialSnapshot;
-    exports.isInitialSnapshotCreated = isInitialSnapshotCreated;
     exports.finalizeResponse = finalizeResponse;
     exports.restoreToSnapshot = restoreToSnapshot;
-    exports.isUndoApplied = isUndoApplied;
-    exports.setUndoApplied = setUndoApplied;
     exports.getSnapshotCount = getSnapshotCount;
     exports.reset = reset;
 });
diff --git a/src/core-ai/editApplyVerification.md b/src/core-ai/editApplyVerification.md
@@ -22,11 +22,12 @@ _snapshots[2] = after R2 edits
 
 ## State Variables
 
-- `_snapshots[]`: flat array of `{ filePath: hash|null }` snapshots
-- `_lastSnapshotAfter`: cumulative state after last completed response
-- `_pendingBeforeSnap`: per-file pre-edit tracking during current response
-- `_initialSnapshotCreated`: whether snapshot 0 has been pushed
-- `_undoApplied`: whether undo/restore has been clicked on any card
+### AISnapshotStore (pure data layer)
+- `_snapshots[]`: flat array of `{ filePath: hash|null }` snapshots. `getSnapshotCount() > 0` replaces the old `_initialSnapshotCreated` flag.
+- `_pendingBeforeSnap`: per-file pre-edit tracking during current response (dedup guard for first-edit-per-file + file list for `finalizeResponse`)
+
+### AIChatPanel (UI state)
+- `_undoApplied`: whether undo/restore has been clicked on any card (UI control for button labels)
 
 ## DOM Layout Example
 
@@ -49,18 +50,18 @@ _snapshots[2] = after R2 edits
 ### AISnapshotStore
 
 - `recordFileBeforeEdit(filePath, previousContent, isNewFile)`: tracks pre-edit state, back-fills all existing snapshots
-- `createInitialSnapshot()`: pushes snapshot 0 from `_lastSnapshotAfter`, returns index 0
-- `isInitialSnapshotCreated()`: returns whether snapshot 0 exists
-- `finalizeResponse()`: builds after-snapshot from current doc content, pushes it, resets `_undoApplied`, returns index (or -1)
+- `createInitialSnapshot()`: pushes empty `{}` as snapshot 0, returns index 0. Must be called *before* `recordFileBeforeEdit` so the back-fill populates it.
+- `getSnapshotCount()`: returns `_snapshots.length` (replaces `isInitialSnapshotCreated()`)
+- `finalizeResponse()`: builds after-snapshot from `_snapshots[last]` + current doc content, pushes it, returns index (or -1)
 - `restoreToSnapshot(index, callback)`: applies `_snapshots[index]` to files, calls `callback(errorCount)`
-- `isUndoApplied()` / `setUndoApplied(val)`: getter/setter for undo state
 - `reset()`: clears all state for new session
 
 ### AIChatPanel
 
 - `_$msgs()`: live DOM query helper — returns `$(".ai-chat-messages")` to avoid stale cached `$messages` reference (see Implementation Notes)
-- `_onToolEdit()`: on first edit per response, inserts initial PUC if not yet created. Diff toggle only (no per-edit undo).
-- `_appendEditSummary()`: calls `finalizeResponse()`, creates summary card with "Undo" or "Restore to this point" button
+- `_undoApplied`: local module state — reset to `false` in `_appendEditSummary()` (after `finalizeResponse()`) and `_newSession()`; set to `true` in `_onRestoreClick()` and `_onUndoClick()`
+- `_onToolEdit()`: on first edit per response, creates initial snapshot (if none) *then* records pre-edit state. Inserts initial PUC. Diff toggle only (no per-edit undo).
+- `_appendEditSummary()`: calls `finalizeResponse()`, resets `_undoApplied`, creates summary card with "Undo" or "Restore to this point" button
 - `_onUndoClick(afterIndex)`: sets `_undoApplied`, resets all buttons to "Restore to this point", restores to `afterIndex - 1`, highlights target element as "Restored", scrolls to it
 - `_onRestoreClick(snapshotIndex)`: sets `_undoApplied`, resets all buttons to "Restore to this point", restores to the given snapshot, marks clicked element as "Restored"
 - `_setStreaming(streaming)`: disables/enables all restore buttons during AI streaming