gui: use stable blockId instead of index for bookmarks/plumb

- Add blockId field to ChatBlock (12-char MD5 hash of counter+name)
- Bookmarks now use blockId instead of volatile list index
- Plumb URLs use blockId: ollie://session/agent#abc123def456
- Add indexForBlockId() to look up current index from stable ID
- Action buttons always visible (no hover flicker)

kde/gui/ChatBlockDelegate.qml

@@ -18,15 +18,13 @@ Column {
     required property var blockSegments
     required property string blockRenderedHtml
     required property int index
-    
+    required property string blockId
-    // Block index for bookmarking
-    property int blockIndex: index
     
     // Bookmark functions (connected from parent)
-    property var addBookmark: function(sid, sn, aid, an, bi, bt, bn, p) { return false }
+    property var addBookmark: function(sid, sn, aid, an, bid, bt, bn, p) { return false }
-    property var removeBookmark: function(sid, aid, bi) { return false }
+    property var removeBookmark: function(sid, aid, bid) { return false }
-    property var checkBookmarked: function(sid, aid, bi) { return false }
+    property var checkBookmarked: function(sid, aid, bid) { return false }
-    property bool isBookmarked: checkBookmarked(ollie.activeSessionId, ollie.activeAgentId, blockIndex)
+    property bool isBookmarked: checkBookmarked(ollie.activeSessionId, ollie.activeAgentId, blockId)
 
     // Expand state based on block type
     property bool blockExpanded: {
@@ -130,11 +128,9 @@ Column {
                 opacity: 0.9
             }
 
-            // Action buttons (visible on hover) — Acme-style tag line
+            // Action buttons
             Row {
                 spacing: 2
-                visible: root.hovered
-                opacity: 0.8
 
                 // Copy block content
                 ToolButton {
@@ -200,7 +196,7 @@ Column {
                     ToolTip.text: root.isBookmarked ? "Remove bookmark" : "Bookmark"
                     onClicked: {
                         if (root.isBookmarked) {
-                            root.removeBookmark(ollie.activeSessionId, ollie.activeAgentId, root.blockIndex)
+                            root.removeBookmark(ollie.activeSessionId, ollie.activeAgentId, root.blockId)
                         } else {
                             var sessionName = ollie.activeSessionName || ollie.activeSessionId
                             var agentName = ollie.activeAgentName || ollie.activeAgentId
@@ -210,7 +206,7 @@ Column {
                                 sessionName,
                                 ollie.activeAgentId,
                                 agentName,
-                                root.blockIndex,
+                                root.blockId,
                                 blockType,
                                 blockName,
                                 preview

kde/gui/ChatPane.qml

@@ -42,6 +42,12 @@ Item {
             chatView.positionViewAtIndex(blockIndex, ListView.Center)
         }
     }
+    function scrollToBlockId(blockId) {
+        var idx = chatModel.indexForBlockId(blockId)
+        if (idx >= 0) {
+            chatView.positionViewAtIndex(idx, ListView.Center)
+        }
+    }
     function trimVisibleBlocks() {
         if (chatModel.count > chatPane.maxVisibleBlocks)
             chatModel.trimFront(chatPane.maxVisibleBlocks)

kde/gui/SessionTree.qml

@@ -421,7 +421,7 @@ Item {
                         width: bookmarksList.width
                         height: theme.fontSize > 0 ? theme.fontSize * 3 : 36
                         
-                        property string ollieUrl: "ollie://" + encodeURIComponent(sessionName) + "/" + encodeURIComponent(agentName) + "#" + blockIndex
+                        property string ollieUrl: "ollie://" + encodeURIComponent(sessionName) + "/" + encodeURIComponent(agentName) + "#" + blockId
                         
                         RowLayout {
                             anchors.fill: parent
@@ -464,7 +464,7 @@ Item {
                                 font.pointSize: theme.fontSize > 0 ? theme.fontSize * 0.9 : 11
                                 implicitWidth: theme.fontSize > 0 ? theme.fontSize * 2 : 28
                                 implicitHeight: theme.fontSize > 0 ? theme.fontSize * 1.8 : 24
-                                onClicked: root.removeBookmark(sessionId, agentId, blockIndex)
+                                onClicked: root.removeBookmark(sessionId, agentId, blockId)
                                 ToolTip.visible: hovered
                                 ToolTip.delay: 500
                                 ToolTip.text: "Remove bookmark"
@@ -474,8 +474,7 @@ Item {
                         onClicked: {
                             // Switch to the session/agent and scroll to block
                             ollie.switchAgent(sessionId, agentId)
-                            // Signal to ChatPane to scroll to blockIndex
+                            chatPane.scrollToBlockId(blockId)
-                            chatPane.scrollToBlock(blockIndex)
                         }
                     }
                 }

kde/gui/chatblockmodel.cpp

@@ -159,6 +159,8 @@ QVariant ChatBlockModel::data(const QModelIndex &index, int role) const
         return b.renderedHtml;
     case SegmentsRole:
         return segmentsToVariant(b.segments);
+    case BlockIdRole:
+        return b.blockId;
     }
     return {};
 }
@@ -191,6 +193,7 @@ QHash<int, QByteArray> ChatBlockModel::roleNames() const
         {ContentRole,  "blockContent"},
         {RenderedHtmlRole, "blockRenderedHtml"},
         {SegmentsRole, "blockSegments"},
+        {BlockIdRole, "blockId"},
     };
 }
 
@@ -258,6 +261,15 @@ void ChatBlockModel::trimFront(int keepCount)
     emit countChanged();
 }
 
+int ChatBlockModel::indexForBlockId(const QString &blockId) const
+{
+    for (int i = 0; i < m_blocks.size(); ++i) {
+        if (m_blocks[i].blockId == blockId)
+            return i;
+    }
+    return -1;
+}
+
 QString ChatBlockModel::getDefaultTextColor() const
 {
     const auto textColor = QApplication::palette().color(QPalette::Text);
@@ -808,6 +820,11 @@ void ChatBlockModel::processLine(const QString &line)
             ChatBlock newBlock;
             newBlock.type = blockTypeFromString(blockName.section(':', 0, 0));
             newBlock.name = blockName.section(':', 1);
+            // Generate stable block ID: sequential counter + type + name hash
+            // The counter ensures uniqueness even for identical type/name pairs
+            QString idSource = QString::number(m_blockIdCounter++) + blockName;
+            newBlock.blockId = QString::fromLatin1(
+                QCryptographicHash::hash(idSource.toUtf8(), QCryptographicHash::Md5).toHex().left(12));
             m_blocks.append(newBlock);
             endInsertRows();
             emit countChanged();

kde/gui/chatblockmodel.h

@@ -65,6 +65,7 @@ struct ChatBlock {
     QString renderedHtml;  // Legacy: full HTML (kept for compatibility)
     QList<BlockSegment> segments;  // Structured segments for interactive rendering
     BlockRenderState renderState;  // Incremental rendering state
+    QString blockId;  // Stable identifier (hash of type+name+first N chars of content)
 };
 
 class ChatBlockModel : public QAbstractListModel
@@ -85,6 +86,7 @@ public:
         ContentRole,
         RenderedHtmlRole,
         SegmentsRole,  // QVariantList of segment maps
+        BlockIdRole,   // Stable block identifier
     };
 
     explicit ChatBlockModel(QObject *parent = nullptr);
@@ -97,6 +99,7 @@ public:
     Q_INVOKABLE void appendData(const QString &text);
     Q_INVOKABLE void reset();
     Q_INVOKABLE void trimFront(int keepCount);
+    Q_INVOKABLE int indexForBlockId(const QString &blockId) const;
 
 signals:
     void countChanged();
@@ -138,6 +141,7 @@ private:
 
     QList<ChatBlock> m_blocks;
     QString m_lineBuffer;
+    quint64 m_blockIdCounter = 0;  // Monotonic counter for stable block IDs
 
     // Context blocks are injected into prompts but hidden from chat rendering.
     bool m_inContext = false;

kde/gui/main.qml

@@ -14,16 +14,16 @@ ApplicationWindow {
     font.pointSize: theme.fontSize > 0 ? theme.fontSize : Qt.application.font.pointSize
 
     // Bookmarks model (non-persistent, GUI state only)
-    // Each entry: { sessionId, sessionName, agentId, agentName, blockIndex, blockType, blockName, preview }
+    // Each entry: { sessionId, sessionName, agentId, agentName, blockId, blockType, blockName, preview }
     ListModel {
         id: bookmarksModel
     }
     
-    function addBookmark(sessionId, sessionName, agentId, agentName, blockIndex, blockType, blockName, preview) {
+    function addBookmark(sessionId, sessionName, agentId, agentName, blockId, blockType, blockName, preview) {
         // Check for duplicate
         for (var i = 0; i < bookmarksModel.count; i++) {
             var b = bookmarksModel.get(i)
-            if (b.sessionId === sessionId && b.agentId === agentId && b.blockIndex === blockIndex) {
+            if (b.sessionId === sessionId && b.agentId === agentId && b.blockId === blockId) {
                 return false
             }
         }
@@ -32,7 +32,7 @@ ApplicationWindow {
             sessionName: sessionName,
             agentId: agentId,
             agentName: agentName,
-            blockIndex: blockIndex,
+            blockId: blockId,
             blockType: blockType,
             blockName: blockName,
             preview: preview.substring(0, 80) + (preview.length > 80 ? "…" : "")
@@ -40,10 +40,10 @@ ApplicationWindow {
         return true
     }
     
-    function removeBookmark(sessionId, agentId, blockIndex) {
+    function removeBookmark(sessionId, agentId, blockId) {
         for (var i = 0; i < bookmarksModel.count; i++) {
             var b = bookmarksModel.get(i)
-            if (b.sessionId === sessionId && b.agentId === agentId && b.blockIndex === blockIndex) {
+            if (b.sessionId === sessionId && b.agentId === agentId && b.blockId === blockId) {
                 bookmarksModel.remove(i)
                 return true
             }
@@ -51,10 +51,10 @@ ApplicationWindow {
         return false
     }
     
-    function isBookmarked(sessionId, agentId, blockIndex) {
+    function isBookmarked(sessionId, agentId, blockId) {
         for (var i = 0; i < bookmarksModel.count; i++) {
             var b = bookmarksModel.get(i)
-            if (b.sessionId === sessionId && b.agentId === agentId && b.blockIndex === blockIndex) {
+            if (b.sessionId === sessionId && b.agentId === agentId && b.blockId === blockId) {
                 return true
             }
         }
@@ -62,17 +62,17 @@ ApplicationWindow {
     }
 
     // Handle plumb messages from the ollie port
-    // URL format: ollie://session/agent#block
+    // URL format: ollie://session/agent#blockId
     function handleOllieMessage(url) {
-        // Parse ollie://session/agent#block
+        // Parse ollie://session/agent#blockId
-        var match = url.match(/^ollie:\/\/([^\/]+)(?:\/([^#]+))?(?:#(\d+))?$/)
+        var match = url.match(/^ollie:\/\/([^\/]+)(?:\/([^#]+))?(?:#([a-f0-9]+))?$/)
         if (!match) {
             console.log("Invalid ollie URL:", url)
             return
         }
         var sessionName = decodeURIComponent(match[1])
         var agentName = match[2] ? decodeURIComponent(match[2]) : ""
-        var blockIndex = match[3] ? parseInt(match[3]) : -1
+        var blockId = match[3] || ""
 
         // Find session by name and switch to it
         var sessions = ollie.sessions
@@ -92,10 +92,10 @@ ApplicationWindow {
                     }
                 }
                 
-                // If block specified, scroll to it after a short delay
+                // If blockId specified, scroll to it after a short delay
-                if (blockIndex >= 0) {
+                if (blockId) {
                     Qt.callLater(function() {
-                        chatPane.scrollToBlock(blockIndex)
+                        chatPane.scrollToBlockId(blockId)
                     })
                 }