diff --git a/.github/workflows/cli-release.yml b/.github/workflows/cli-release.yml
index 92c8da31..b3a13d14 100644
--- a/.github/workflows/cli-release.yml
+++ b/.github/workflows/cli-release.yml
@@ -273,7 +273,7 @@ jobs:
         with:
           files: ${{ steps.pkg.outputs.files }}
           generate_release_notes: true
-          draft: false
+          draft: true
           prerelease: ${{ contains(github.ref, '-rc') || contains(github.ref, '-beta') || contains(github.ref, '-alpha') }}
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/desktop-release.yml b/.github/workflows/desktop-release.yml
index 488f52f0..1c0a9223 100644
--- a/.github/workflows/desktop-release.yml
+++ b/.github/workflows/desktop-release.yml
@@ -474,3 +474,71 @@ jobs:
           draft: true
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+
+
+  contributors:
+    name: Append contributors to release notes
+    if: startsWith(github.ref, 'refs/tags/v')
+    needs: [ release ]
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - name: Checkout (full history for git log)
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Build contributors section and append to release
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        shell: bash
+        run: |
+          set -euo pipefail
+          TAG="${{ github.ref_name }}"
+
+          # Find the previous tag (the one before this one)
+          PREV_TAG=$(git tag --sort=-version:refname | grep -v "^${TAG}$" | head -n1 || true)
+
+          if [ -n "$PREV_TAG" ]; then
+            RANGE="${PREV_TAG}..${TAG}"
+            echo "Contributors from $RANGE"
+          else
+            RANGE="${TAG}"
+            echo "No previous tag found — listing all contributors up to $TAG"
+          fi
+
+          # Collect unique authors: "Login (Name)" sorted, bots excluded
+          mapfile -t AUTHORS < <(
+            git log "$RANGE" --format='%aN|%aE' \
+              | sort -u \
+              | grep -viE '\[bot\]|noreply\.github\.com' \
+              | awk -F'|' '{print $1}' \
+              | sort -u
+          )
+
+          if [ ${#AUTHORS[@]} -eq 0 ]; then
+            echo "No human contributors found — skipping append."
+            exit 0
+          fi
+
+          echo "Found ${#AUTHORS[@]} contributor(s): ${AUTHORS[*]}"
+
+          # Build markdown section
+          SECTION=$'\n\n## Contributors\n\nThank you to everyone who contributed to this release! 🎉\n\n'
+          for AUTHOR in "${AUTHORS[@]}"; do
+            SECTION+="- ${AUTHOR}"$'\n'
+          done
+
+          # Fetch current release body
+          CURRENT_BODY=$(gh release view "$TAG" --json body --jq '.body' 2>/dev/null || echo "")
+
+          # Remove any previously appended Contributors section (idempotent re-runs)
+          STRIPPED=$(echo "$CURRENT_BODY" | sed '/^## Contributors/,$ d')
+
+          NEW_BODY="${STRIPPED}${SECTION}"
+
+          gh release edit "$TAG" --notes "$NEW_BODY"
+          echo "✅ Contributors section appended to release $TAG"
+
diff --git a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ChatInputField.kt b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ChatInputField.kt
index 7254655c..3ddb8be3 100644
--- a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ChatInputField.kt
+++ b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ChatInputField.kt
@@ -32,6 +32,8 @@ import androidx.compose.material.icons.filled.ChevronRight
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Edit
 import androidx.compose.material.icons.filled.Image
+import androidx.compose.material.icons.filled.KeyboardArrowDown
+import androidx.compose.material.icons.filled.KeyboardArrowUp
 import androidx.compose.material.icons.filled.Stop
 import androidx.compose.material3.Badge
 import androidx.compose.material3.BadgedBox
@@ -75,6 +77,7 @@ import androidx.compose.ui.window.Popup
 import io.askimo.core.chat.dto.ChatMessageDTO
 import io.askimo.core.chat.dto.FileAttachmentDTO
 import io.askimo.core.chat.service.ChatSessionService
+import io.askimo.core.chat.util.FileContentExtractor
 import io.askimo.core.config.AppConfig
 import io.askimo.core.event.EventBus
 import io.askimo.core.event.error.AppErrorEvent
@@ -1104,53 +1107,159 @@ private fun fileAttachmentItem(
     attachment: FileAttachmentDTO,
     onRemove: () -> Unit,
 ) {
+    var expanded by remember { mutableStateOf(false) }
+    var previewContent by remember { mutableStateOf<String?>(null) }
+    var isLoadingPreview by remember { mutableStateOf(false) }
+
+    // Determine if the file is previewable as text — delegate to FileContentExtractor
+    val isTextFile = FileContentExtractor.isTextFile(attachment.fileName)
+
+    LaunchedEffect(expanded) {
+        if (expanded && isTextFile && previewContent == null && !isLoadingPreview) {
+            isLoadingPreview = true
+            previewContent = withContext(Dispatchers.IO) {
+                try {
+                    val file = attachment.filePath?.let { java.io.File(it) }
+                    if (file != null && file.exists() && file.length() < 512 * 1024) {
+                        // Read up to 200 lines for preview
+                        file.bufferedReader().use { reader ->
+                            val lines = reader.readLines()
+                            val preview = lines.take(200).joinToString("\n")
+                            if (lines.size > 200) {
+                                "$preview\n… (${LocalizationManager.getString("chat.attachment.preview.more.lines", lines.size - 200)})"
+                            } else {
+                                preview
+                            }
+                        }
+                    } else if (file != null && !file.exists()) {
+                        LocalizationManager.getString("chat.attachment.preview.file.not.found")
+                    } else {
+                        LocalizationManager.getString("chat.attachment.preview.too.large")
+                    }
+                } catch (e: Exception) {
+                    LocalizationManager.getString("chat.attachment.preview.cannot.read", e.message ?: "")
+                }
+            }
+            isLoadingPreview = false
+        }
+    }
+
     Card(
         modifier = Modifier.fillMaxWidth(),
         colors = AppComponents.surfaceVariantCardColors(),
     ) {
-        Row(
-            modifier = Modifier
-                .fillMaxWidth()
-                .padding(8.dp),
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.SpaceBetween,
-        ) {
+        Column(modifier = Modifier.fillMaxWidth()) {
+            // Header row
             Row(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .then(
+                        if (isTextFile) {
+                            Modifier.clickable(
+                                interactionSource = remember { MutableInteractionSource() },
+                                indication = null,
+                                onClick = { expanded = !expanded },
+                            ).pointerHoverIcon(PointerIcon.Hand)
+                        } else {
+                            Modifier
+                        },
+                    )
+                    .padding(8.dp),
                 verticalAlignment = Alignment.CenterVertically,
-                horizontalArrangement = Arrangement.spacedBy(8.dp),
-                modifier = Modifier.weight(1f),
+                horizontalArrangement = Arrangement.SpaceBetween,
             ) {
-                Icon(
-                    imageVector = Icons.Default.AttachFile,
-                    contentDescription = null,
-                    modifier = Modifier.size(16.dp),
-                    tint = MaterialTheme.colorScheme.onSurface,
-                )
-                Column {
-                    Text(
-                        text = attachment.fileName,
-                        style = MaterialTheme.typography.bodySmall,
-                        color = MaterialTheme.colorScheme.onSurface,
-                    )
-                    Text(
-                        text = formatFileSize(attachment.size),
-                        style = MaterialTheme.typography.labelSmall,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                Row(
+                    verticalAlignment = Alignment.CenterVertically,
+                    horizontalArrangement = Arrangement.spacedBy(8.dp),
+                    modifier = Modifier.weight(1f),
+                ) {
+                    Icon(
+                        imageVector = Icons.Default.AttachFile,
+                        contentDescription = null,
+                        modifier = Modifier.size(16.dp),
+                        tint = MaterialTheme.colorScheme.onSurface,
                     )
+                    Column {
+                        Text(
+                            text = attachment.fileName,
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.onSurface,
+                        )
+                        Text(
+                            text = formatFileSize(attachment.size),
+                            style = MaterialTheme.typography.labelSmall,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        )
+                    }
+                }
+                Row(
+                    horizontalArrangement = Arrangement.spacedBy(4.dp),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    if (isTextFile) {
+                        Icon(
+                            imageVector = if (expanded) Icons.Default.KeyboardArrowUp else Icons.Default.KeyboardArrowDown,
+                            contentDescription = if (expanded) "Collapse preview" else "Expand preview",
+                            modifier = Modifier.size(16.dp),
+                            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                        )
+                    }
+                    IconButton(
+                        onClick = onRemove,
+                        modifier = Modifier
+                            .size(24.dp)
+                            .pointerHoverIcon(PointerIcon.Hand),
+                    ) {
+                        Icon(
+                            imageVector = Icons.Default.Close,
+                            contentDescription = stringResource("chat.attachment.remove"),
+                            modifier = Modifier.size(16.dp),
+                            tint = MaterialTheme.colorScheme.onSurface,
+                        )
+                    }
                 }
             }
-            IconButton(
-                onClick = onRemove,
-                modifier = Modifier
-                    .size(24.dp)
-                    .pointerHoverIcon(PointerIcon.Hand),
-            ) {
-                Icon(
-                    imageVector = Icons.Default.Close,
-                    contentDescription = stringResource("chat.attachment.remove"),
-                    modifier = Modifier.size(16.dp),
-                    tint = MaterialTheme.colorScheme.onSurface,
-                )
+
+            // Inline preview panel
+            if (expanded && isTextFile) {
+                HorizontalDivider()
+                Box(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .heightIn(max = 240.dp)
+                        .background(MaterialTheme.colorScheme.surface.copy(alpha = 0.5f))
+                        .padding(horizontal = 12.dp, vertical = 8.dp),
+                ) {
+                    when {
+                        isLoadingPreview -> {
+                            Row(
+                                horizontalArrangement = Arrangement.spacedBy(8.dp),
+                                verticalAlignment = Alignment.CenterVertically,
+                            ) {
+                                CircularProgressIndicator(modifier = Modifier.size(14.dp), strokeWidth = 2.dp)
+                                Text(
+                                    text = stringResource("chat.attachment.preview.loading"),
+                                    style = MaterialTheme.typography.labelSmall,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                )
+                            }
+                        }
+
+                        previewContent != null -> {
+                            val scrollState = rememberScrollState()
+                            androidx.compose.foundation.text.selection.SelectionContainer {
+                                Text(
+                                    text = previewContent!!,
+                                    style = MaterialTheme.typography.labelSmall.copy(
+                                        fontFamily = androidx.compose.ui.text.font.FontFamily.Monospace,
+                                    ),
+                                    color = MaterialTheme.colorScheme.onSurface,
+                                    modifier = Modifier.verticalScroll(scrollState),
+                                )
+                            }
+                        }
+                    }
+                }
             }
         }
     }
diff --git a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ChatView.kt b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ChatView.kt
index aa600569..653294b4 100644
--- a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ChatView.kt
+++ b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ChatView.kt
@@ -104,6 +104,7 @@ import kotlinx.coroutines.withContext
 import org.koin.core.context.GlobalContext
 import java.io.File
 import java.time.LocalDateTime
+import java.util.UUID.randomUUID
 
 private val log = currentFileLogger()
 
@@ -149,10 +150,16 @@ fun chatView(
 
     // Internal state management for ChatView
     val scope = rememberCoroutineScope()
-    var inputText by remember(initialInputText) { mutableStateOf(initialInputText) }
-    var attachments by remember(initialAttachments) { mutableStateOf(initialAttachments) }
-    var editingMessage by remember(initialEditingMessage) { mutableStateOf(initialEditingMessage) }
-    var editingAIMessage by remember { mutableStateOf<ChatMessageDTO?>(null) }
+    var inputText by remember(sessionId, initialInputText) { mutableStateOf(initialInputText) }
+    var attachments by remember(sessionId, initialAttachments) { mutableStateOf(initialAttachments) }
+    var editingMessage by remember(sessionId, initialEditingMessage) { mutableStateOf(initialEditingMessage) }
+    var editingAIMessage by remember(sessionId) { mutableStateOf<ChatMessageDTO?>(null) }
+
+    // When there is no project (e.g. user clicked "New Chat"), drop any pending
+    // attachments that were added from the project side panel.
+    LaunchedEffect(project) {
+        if (project == null) attachments = emptyList()
+    }
 
     // Notify parent of state changes
     LaunchedEffect(inputText, attachments, editingMessage) {
@@ -1086,6 +1093,28 @@ fun chatView(
                 ragIndexingPercentage = ragIndexingPercentage,
                 isExpanded = sidePanelExpanded,
                 onExpandedChange = { sidePanelExpanded = it },
+                onAddToChat = { filePaths ->
+                    val newAttachments = filePaths.map { path ->
+                        val file = File(path)
+                        FileAttachmentDTO(
+                            id = randomUUID().toString(),
+                            messageId = "",
+                            sessionId = sessionId ?: "",
+                            fileName = file.name,
+                            mimeType = file.extension,
+                            size = file.length(),
+                            createdAt = LocalDateTime.now(),
+                            content = null,
+                            filePath = file.absolutePath,
+                        )
+                    }
+                    // Merge, avoiding duplicates by path
+                    val existingPaths = attachments.mapNotNull { it.filePath }.toSet()
+                    val toAdd = newAttachments.filter { it.filePath !in existingPaths }
+                    if (toAdd.isNotEmpty()) {
+                        attachments = attachments + toAdd
+                    }
+                },
                 modifier = Modifier.fillMaxHeight(),
             )
         }
diff --git a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/FileViewerPane.kt b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/FileViewerPane.kt
index 36975f07..c25aadc9 100644
--- a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/FileViewerPane.kt
+++ b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/FileViewerPane.kt
@@ -23,10 +23,10 @@ import androidx.compose.foundation.text.selection.SelectionContainer
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.InsertDriveFile
+import androidx.compose.material.icons.automirrored.filled.OpenInNew
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.ContentCopy
 import androidx.compose.material.icons.filled.FolderOpen
-import androidx.compose.material.icons.filled.OpenInNew
 import androidx.compose.material.icons.filled.Warning
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
@@ -161,7 +161,7 @@ fun fileViewerPane(
                         modifier = Modifier.size(28.dp).pointerHoverIcon(PointerIcon.Hand),
                     ) {
                         Icon(
-                            imageVector = Icons.Default.OpenInNew,
+                            imageVector = Icons.AutoMirrored.Filled.OpenInNew,
                             contentDescription = stringResource("file.viewer.open.external"),
                             tint = MaterialTheme.colorScheme.onSurface,
                             modifier = Modifier.size(15.dp),
@@ -252,7 +252,7 @@ fun fileViewerPane(
                     Icon(
                         imageVector = Icons.Default.Warning,
                         contentDescription = null,
-                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                        tint = MaterialTheme.colorScheme.tertiary,
                         modifier = Modifier.size(32.dp),
                     )
                 },
@@ -322,10 +322,15 @@ private fun viewerPlaceholder(
                 Icon(
                     imageVector = Icons.Default.FolderOpen,
                     contentDescription = null,
+                    tint = MaterialTheme.colorScheme.onSurface,
                     modifier = Modifier.size(15.dp),
                 )
                 Spacer(Modifier.size(6.dp))
-                Text(text = actionLabel, style = MaterialTheme.typography.bodySmall)
+                Text(
+                    text = actionLabel,
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurface,
+                )
             }
         }
     }
diff --git a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ProjectSidePanel.kt b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ProjectSidePanel.kt
index 887c403f..49176daf 100644
--- a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ProjectSidePanel.kt
+++ b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/ProjectSidePanel.kt
@@ -98,6 +98,7 @@ fun projectSidePanel(
     ragIndexingPercentage: Int?,
     isExpanded: Boolean,
     onExpandedChange: (Boolean) -> Unit,
+    onAddToChat: ((List<String>) -> Unit)? = null,
     modifier: Modifier = Modifier,
 ) {
     var selectedTab by remember { mutableStateOf(PanelTab.RAG_SOURCES) }
@@ -304,6 +305,7 @@ fun projectSidePanel(
                                             )
                                         }
                                     },
+                                    onAddToChat = onAddToChat,
                                 )
                             }
 
@@ -437,6 +439,7 @@ private fun ragSourcesTabContent(
     ragIndexingPercentage: Int?,
     onAddMaterial: () -> Unit,
     onRemove: (KnowledgeSourceConfig) -> Unit,
+    onAddToChat: ((List<String>) -> Unit)? = null,
 ) {
     var selectedNode by remember { mutableStateOf<TreeNode?>(null) }
     var viewerHeightRatio by remember {
@@ -536,6 +539,7 @@ private fun ragSourcesTabContent(
                             }
                             onRemove(source)
                         },
+                        onAddToChat = onAddToChat,
                     )
                 }
             }
diff --git a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/RagSourcesTree.kt b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/RagSourcesTree.kt
index 0408fd06..e4b6a6d6 100644
--- a/desktop-shared/src/main/kotlin/io/askimo/ui/chat/RagSourcesTree.kt
+++ b/desktop-shared/src/main/kotlin/io/askimo/ui/chat/RagSourcesTree.kt
@@ -25,20 +25,28 @@ import androidx.compose.foundation.rememberScrollbarAdapter
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.InsertDriveFile
 import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
+import androidx.compose.material.icons.filled.AddCircleOutline
+import androidx.compose.material.icons.filled.AttachFile
+import androidx.compose.material.icons.filled.CheckCircle
 import androidx.compose.material.icons.filled.ContentCopy
 import androidx.compose.material.icons.filled.Folder
 import androidx.compose.material.icons.filled.FolderOpen
 import androidx.compose.material.icons.filled.KeyboardArrowDown
 import androidx.compose.material.icons.filled.Language
 import androidx.compose.material.icons.filled.Remove
+import androidx.compose.material3.Button
 import androidx.compose.material3.DropdownMenu
 import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.mutableStateSetOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
@@ -47,6 +55,7 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.pointer.PointerButton
 import androidx.compose.ui.input.pointer.PointerIcon
 import androidx.compose.ui.input.pointer.pointerHoverIcon
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.DpOffset
 import androidx.compose.ui.unit.dp
@@ -67,11 +76,16 @@ import java.net.URI
  * Tree view component for displaying RAG knowledge sources.
  * Shows files and folders with expandable/collapsible functionality.
  *
+ * When [onAddToChat] is provided, each file/folder row gains a "+" quick-add button,
+ * a context-menu "Add to chat" option, and a sticky bottom bar for multi-file selection.
+ *
  * @param sources          Knowledge source configs to display.
  * @param modifier         Optional modifier.
  * @param selectedNode     Currently selected node (hoisted to allow viewer integration).
  * @param onNodeSelected   Called when a node is selected; passes `null` to deselect.
  * @param onRemove         Called when the user removes a knowledge source.
+ * @param onAddToChat      Called with a list of file paths to attach to the current chat message.
+ *                         Pass `null` to disable the feature.
  */
 @OptIn(ExperimentalFoundationApi::class)
 @Composable
@@ -81,7 +95,11 @@ fun ragSourcesTree(
     selectedNode: TreeNode? = null,
     onNodeSelected: (TreeNode?) -> Unit = {},
     onRemove: (KnowledgeSourceConfig) -> Unit = {},
+    onAddToChat: ((List<String>) -> Unit)? = null,
 ) {
+    // Paths currently checked for bulk "Add to chat"
+    val chatSelection = remember { mutableStateSetOf<String>() }
+
     // Convert sources to tree nodes
     val treeNodes = remember(sources) {
         sources.map { source ->
@@ -112,39 +130,107 @@ fun ragSourcesTree(
 
     val listState = rememberLazyListState()
 
-    Box(modifier = modifier) {
-        LazyColumn(
-            state = listState,
-            modifier = Modifier
-                .fillMaxWidth()
-                .padding(start = 16.dp, end = 22.dp), // left padding matches header; right leaves room for scrollbar
-            verticalArrangement = Arrangement.spacedBy(4.dp),
-        ) {
-            items(treeNodes) { node ->
-                treeNodeItem(
-                    node = node,
-                    level = 0,
-                    selectedNode = selectedNode,
-                    onNodeSelected = onNodeSelected,
-                    onRemove = onRemove,
-                )
+    Column(modifier = modifier) {
+        Box(modifier = Modifier.weight(1f)) {
+            LazyColumn(
+                state = listState,
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(start = 16.dp, end = 22.dp),
+                verticalArrangement = Arrangement.spacedBy(4.dp),
+            ) {
+                items(treeNodes) { node ->
+                    treeNodeItem(
+                        node = node,
+                        level = 0,
+                        selectedNode = selectedNode,
+                        onNodeSelected = onNodeSelected,
+                        onRemove = onRemove,
+                        chatSelection = chatSelection,
+                        onAddToChat = onAddToChat,
+                    )
+                }
             }
+
+            VerticalScrollbar(
+                modifier = Modifier
+                    .align(Alignment.CenterEnd)
+                    .fillMaxHeight(),
+                adapter = rememberScrollbarAdapter(listState),
+                style = ScrollbarStyle(
+                    minimalHeight = 16.dp,
+                    thickness = 6.dp,
+                    shape = MaterialTheme.shapes.small,
+                    hoverDurationMillis = 300,
+                    unhoverColor = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.4f),
+                    hoverColor = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.7f),
+                ),
+            )
         }
 
-        VerticalScrollbar(
-            modifier = Modifier
-                .align(Alignment.CenterEnd)
-                .fillMaxHeight(),
-            adapter = rememberScrollbarAdapter(listState),
-            style = ScrollbarStyle(
-                minimalHeight = 16.dp,
-                thickness = 6.dp,
-                shape = MaterialTheme.shapes.small,
-                hoverDurationMillis = 300,
-                unhoverColor = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.4f),
-                hoverColor = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.7f),
-            ),
-        )
+        // Sticky bottom action bar — only shown when files are selected for chat
+        if (onAddToChat != null && chatSelection.isNotEmpty()) {
+            HorizontalDivider()
+            Row(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .background(MaterialTheme.colorScheme.secondaryContainer.copy(alpha = 0.4f))
+                    .padding(horizontal = 12.dp, vertical = 6.dp),
+                horizontalArrangement = Arrangement.SpaceBetween,
+                verticalAlignment = Alignment.CenterVertically,
+            ) {
+                Row(
+                    horizontalArrangement = Arrangement.spacedBy(6.dp),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    Icon(
+                        imageVector = Icons.Default.AttachFile,
+                        contentDescription = null,
+                        tint = MaterialTheme.colorScheme.onSecondaryContainer,
+                        modifier = Modifier.size(16.dp),
+                    )
+                    Text(
+                        text = stringResource("rag.tree.chat.selected", chatSelection.size),
+                        style = MaterialTheme.typography.labelMedium,
+                        color = MaterialTheme.colorScheme.onSecondaryContainer,
+                    )
+                }
+                Row(
+                    horizontalArrangement = Arrangement.spacedBy(4.dp),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    TextButton(
+                        onClick = { chatSelection.clear() },
+                        modifier = Modifier.pointerHoverIcon(PointerIcon.Hand),
+                    ) {
+                        Text(
+                            text = stringResource("rag.tree.chat.clear"),
+                            style = MaterialTheme.typography.labelSmall,
+                            color = MaterialTheme.colorScheme.onSecondaryContainer,
+                        )
+                    }
+                    Button(
+                        onClick = {
+                            onAddToChat(chatSelection.toList())
+                            chatSelection.clear()
+                        },
+                        modifier = Modifier.pointerHoverIcon(PointerIcon.Hand),
+                    ) {
+                        Icon(
+                            imageVector = Icons.Default.AttachFile,
+                            contentDescription = null,
+                            modifier = Modifier.size(14.dp),
+                        )
+                        Text(
+                            text = stringResource("rag.tree.chat.add"),
+                            style = MaterialTheme.typography.labelSmall,
+                            fontWeight = FontWeight.Medium,
+                            modifier = Modifier.padding(start = 4.dp),
+                        )
+                    }
+                }
+            }
+        }
     }
 }
 
@@ -192,11 +278,13 @@ private fun treeNodeItem(
     selectedNode: TreeNode?,
     onNodeSelected: (TreeNode) -> Unit,
     onRemove: (KnowledgeSourceConfig) -> Unit,
+    chatSelection: androidx.compose.runtime.snapshots.SnapshotStateSet<String> = remember { mutableStateSetOf() },
+    onAddToChat: ((List<String>) -> Unit)? = null,
     modifier: Modifier = Modifier,
 ) {
     when (node) {
-        is FolderTreeNode -> folderNodeItem(node, level, selectedNode, onNodeSelected, onRemove, modifier)
-        is FileTreeNode -> fileNodeItem(node, level, selectedNode, onNodeSelected, onRemove, modifier)
+        is FolderTreeNode -> folderNodeItem(node, level, selectedNode, onNodeSelected, onRemove, chatSelection, onAddToChat, modifier)
+        is FileTreeNode -> fileNodeItem(node, level, selectedNode, onNodeSelected, onRemove, chatSelection, onAddToChat, modifier)
         is UrlTreeNode -> urlNodeItem(node, level, selectedNode, onNodeSelected, onRemove, modifier)
     }
 }
@@ -212,6 +300,8 @@ private fun folderNodeItem(
     selectedNode: TreeNode?,
     onNodeSelected: (TreeNode) -> Unit,
     onRemove: (KnowledgeSourceConfig) -> Unit,
+    chatSelection: androidx.compose.runtime.snapshots.SnapshotStateSet<String> = remember { mutableStateSetOf() },
+    onAddToChat: ((List<String>) -> Unit)? = null,
     modifier: Modifier = Modifier,
 ) {
     var isExpanded by remember { mutableStateOf(false) }
@@ -235,7 +325,9 @@ private fun folderNodeItem(
     Column(modifier = modifier) {
         // Folder row
         themedTooltip(text = node.fullPath) {
-            Box {
+            Box(
+                modifier = Modifier.fillMaxWidth(),
+            ) {
                 Row(
                     modifier = Modifier
                         .fillMaxWidth()
@@ -274,11 +366,7 @@ private fun folderNodeItem(
 
                     // Folder icon
                     Icon(
-                        imageVector = if (isExpanded) {
-                            Icons.Default.FolderOpen
-                        } else {
-                            Icons.Default.Folder
-                        },
+                        imageVector = if (isExpanded) Icons.Default.FolderOpen else Icons.Default.Folder,
                         contentDescription = null,
                         tint = AppComponents.secondaryIconColor(),
                         modifier = Modifier.size(18.dp),
@@ -293,9 +381,10 @@ private fun folderNodeItem(
                         overflow = TextOverflow.Ellipsis,
                         modifier = Modifier.weight(1f),
                     )
+                    // No "Add to chat" button for folders — only individual files can be attached
                 }
 
-                // Context menu
+                // Context menu — no "Add to chat" option for folders
                 DropdownMenu(
                     expanded = showContextMenu,
                     onDismissRequest = { showContextMenu = false },
@@ -345,6 +434,8 @@ private fun folderNodeItem(
                         selectedNode = selectedNode,
                         onNodeSelected = onNodeSelected,
                         onRemove = onRemove,
+                        chatSelection = chatSelection,
+                        onAddToChat = onAddToChat,
                     )
                 }
             }
@@ -363,14 +454,17 @@ private fun fileNodeItem(
     selectedNode: TreeNode?,
     onNodeSelected: (TreeNode) -> Unit,
     onRemove: (KnowledgeSourceConfig) -> Unit,
+    chatSelection: androidx.compose.runtime.snapshots.SnapshotStateSet<String> = remember { mutableStateSetOf() },
+    onAddToChat: ((List<String>) -> Unit)? = null,
     modifier: Modifier = Modifier,
 ) {
     var showContextMenu by remember { mutableStateOf(false) }
     val isSelected = selectedNode == node
-    val backgroundColor = if (isSelected) {
-        MaterialTheme.colorScheme.primaryContainer.copy(alpha = 0.3f)
-    } else {
-        Color.Transparent
+    val isInChatSelection = node.path in chatSelection
+    val backgroundColor = when {
+        isInChatSelection -> MaterialTheme.colorScheme.secondaryContainer.copy(alpha = 0.35f)
+        isSelected -> MaterialTheme.colorScheme.primaryContainer.copy(alpha = 0.3f)
+        else -> Color.Transparent
     }
 
     themedTooltip(text = node.fullPath) {
@@ -412,6 +506,35 @@ private fun fileNodeItem(
                     overflow = TextOverflow.Ellipsis,
                     modifier = Modifier.weight(1f),
                 )
+
+                // "Add to chat" quick button
+                if (onAddToChat != null) {
+                    if (isInChatSelection) {
+                        IconButton(
+                            onClick = { chatSelection.remove(node.path) },
+                            modifier = Modifier.size(20.dp).pointerHoverIcon(PointerIcon.Hand),
+                        ) {
+                            Icon(
+                                imageVector = Icons.Default.CheckCircle,
+                                contentDescription = stringResource("rag.tree.chat.deselect"),
+                                tint = MaterialTheme.colorScheme.secondary,
+                                modifier = Modifier.size(16.dp),
+                            )
+                        }
+                    } else {
+                        IconButton(
+                            onClick = { chatSelection.add(node.path) },
+                            modifier = Modifier.size(20.dp).pointerHoverIcon(PointerIcon.Hand),
+                        ) {
+                            Icon(
+                                imageVector = Icons.Default.AddCircleOutline,
+                                contentDescription = stringResource("rag.tree.chat.select"),
+                                tint = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.6f),
+                                modifier = Modifier.size(16.dp),
+                            )
+                        }
+                    }
+                }
             }
 
             // Context menu
@@ -420,6 +543,32 @@ private fun fileNodeItem(
                 onDismissRequest = { showContextMenu = false },
                 offset = DpOffset(x = 0.dp, y = 0.dp),
             ) {
+                if (onAddToChat != null) {
+                    if (isInChatSelection) {
+                        DropdownMenuItem(
+                            text = { Text(stringResource("rag.tree.chat.deselect")) },
+                            onClick = {
+                                chatSelection.remove(node.path)
+                                showContextMenu = false
+                            },
+                            leadingIcon = {
+                                Icon(Icons.Default.CheckCircle, contentDescription = null)
+                            },
+                        )
+                    } else {
+                        DropdownMenuItem(
+                            text = { Text(stringResource("rag.tree.chat.select")) },
+                            onClick = {
+                                chatSelection.add(node.path)
+                                showContextMenu = false
+                            },
+                            leadingIcon = {
+                                Icon(Icons.Default.AddCircleOutline, contentDescription = null)
+                            },
+                        )
+                    }
+                    HorizontalDivider()
+                }
                 DropdownMenuItem(
                     text = { Text(stringResource("rag.tree.file.preview")) },
                     onClick = {
diff --git a/desktop-shared/src/main/resources/i18n/messages.properties b/desktop-shared/src/main/resources/i18n/messages.properties
index 107a22c7..a1127e41 100644
--- a/desktop-shared/src/main/resources/i18n/messages.properties
+++ b/desktop-shared/src/main/resources/i18n/messages.properties
@@ -486,6 +486,11 @@ chat.tools.button.disabled=Available Tools ({0} disabled)
 chat.input.placeholder=Type your message... (Enter to send, Shift+Enter for new line)
 chat.select.file=Select File(s)
 chat.attachment.remove=Remove attachment
+chat.attachment.preview.loading=Loading preview\u2026
+chat.attachment.preview.file.not.found=(File not found)
+chat.attachment.preview.too.large=(File too large to preview)
+chat.attachment.preview.cannot.read=(Cannot read file: {0})
+chat.attachment.preview.more.lines={0} more lines
 
 # Sessions View
 sessions.title=Chat Sessions
@@ -872,7 +877,6 @@ knowledge.source.type.url=URL (web content)
 # MCP Server Management
 mcp.servers.title=MCP Server Templates
 mcp.servers.description=Manage Model Context Protocol server templates that can be used across projects
-mcp.servers.add=Add Server Template
 mcp.servers.edit=Edit Template
 mcp.servers.delete=Delete Template
 mcp.servers.delete.confirm.title=Delete MCP Server Template?
@@ -1096,6 +1100,11 @@ rag.tree.url.open=Open in Browser
 rag.tree.url.copy=Copy URL
 rag.tree.remove=Remove Reference Material
 rag.tree.file.preview=Preview File
+rag.tree.chat.select=Add to Chat
+rag.tree.chat.deselect=Remove from Chat
+rag.tree.chat.selected={0} file(s) selected
+rag.tree.chat.clear=Clear
+rag.tree.chat.add=Add to Chat
 
 # File Viewer Pane
 file.viewer.loading=Loading...
diff --git a/desktop-shared/src/main/resources/i18n/messages_de.properties b/desktop-shared/src/main/resources/i18n/messages_de.properties
index 297a4d81..3e45268c 100644
--- a/desktop-shared/src/main/resources/i18n/messages_de.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_de.properties
@@ -488,6 +488,11 @@ chat.tools.button.disabled=Verfügbare Tools ({0} deaktiviert)
 chat.input.placeholder=Nachricht eingeben... (Enter zum Senden, Shift+Enter für neue Zeile)
 chat.select.file=Datei(en) auswählen
 chat.attachment.remove=Anhang entfernen
+chat.attachment.preview.loading=Vorschau wird geladen…
+chat.attachment.preview.file.not.found=(Datei nicht gefunden)
+chat.attachment.preview.too.large=(Datei zu groß für eine Vorschau)
+chat.attachment.preview.cannot.read=(Datei kann nicht gelesen werden: {0})
+chat.attachment.preview.more.lines={0} weitere Zeilen
 
 # Sessions View
 sessions.title=Chatsitzungen
@@ -878,7 +883,6 @@ knowledge.source.type.url=URL (Webinhalte)
 # MCP Server Management
 mcp.servers.title=MCP-Servervorlagen
 mcp.servers.description=Verwalten von Model-Context-Protocol-Servervorlagen, die projektübergreifend verwendet werden können
-mcp.servers.add=Servervorlage hinzufügen
 mcp.servers.edit=Vorlage bearbeiten
 mcp.servers.delete=Vorlage löschen
 mcp.servers.delete.confirm.title=MCP-Servervorlage löschen?
@@ -1102,6 +1106,23 @@ rag.tree.file.copy.path=Pfad kopieren
 rag.tree.url.open=Im Browser öffnen
 rag.tree.url.copy=URL kopieren
 rag.tree.remove=Referenzmaterial entfernen
+rag.tree.file.preview=Dateivorschau
+rag.tree.chat.select=Zum Chat hinzufügen
+rag.tree.chat.deselect=Aus dem Chat entfernen
+rag.tree.chat.selected={0} Datei(en) ausgewählt
+rag.tree.chat.clear=Leeren
+rag.tree.chat.add=Zum Chat hinzufügen
+
+# File Viewer Pane
+file.viewer.loading=Wird geladen...
+file.viewer.lines={0} Zeilen
+file.viewer.copy=Inhalt kopieren
+file.viewer.close=Viewer schließen
+file.viewer.open.external=Extern öffnen
+file.viewer.binary=Binärdatei — Vorschau als Text nicht möglich.
+file.viewer.too.large=Datei ist zu groß für eine Vorschau ({0} KB). Das Maximum liegt bei 512 KB.
+file.viewer.error=Datei konnte nicht gelesen werden: {0}
+file.viewer.select.prompt=Wählen Sie eine Datei aus dem Baum oben aus, um ihren Inhalt als Vorschau anzuzeigen
 
 # Project Side Panel
 panel.tab.rag.sources=RAG-Quellen
diff --git a/desktop-shared/src/main/resources/i18n/messages_es.properties b/desktop-shared/src/main/resources/i18n/messages_es.properties
index bbbdcd29..3360b146 100644
--- a/desktop-shared/src/main/resources/i18n/messages_es.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_es.properties
@@ -487,6 +487,11 @@ chat.tools.button.disabled=Herramientas disponibles ({0} deshabilitadas)
 chat.input.placeholder=Escribe tu mensaje... (Enter para enviar, Shift+Enter para nueva línea)
 chat.select.file=Seleccionar archivo(s)
 chat.attachment.remove=Eliminar archivo adjunto
+chat.attachment.preview.loading=Cargando vista previa…
+chat.attachment.preview.file.not.found=(Archivo no encontrado)
+chat.attachment.preview.too.large=(Archivo demasiado grande para la vista previa)
+chat.attachment.preview.cannot.read=(No se puede leer el archivo: {0})
+chat.attachment.preview.more.lines={0} líneas más
 
 # Sessions View
 sessions.title=Sesiones de chat
@@ -875,7 +880,6 @@ knowledge.source.type.url=URL (contenido web)
 # MCP Server Management
 mcp.servers.title=Plantillas de servidores MCP
 mcp.servers.description=Gestiona plantillas de servidores de Model Context Protocol que pueden reutilizarse en varios proyectos
-mcp.servers.add=Agregar plantilla de servidor
 mcp.servers.edit=Editar plantilla
 mcp.servers.delete=Eliminar plantilla
 mcp.servers.delete.confirm.title=¿Eliminar plantilla de servidor MCP?
@@ -1100,6 +1104,23 @@ rag.tree.file.copy.path=Copiar ruta
 rag.tree.url.open=Abrir en el navegador
 rag.tree.url.copy=Copiar URL
 rag.tree.remove=Eliminar material de referencia
+rag.tree.file.preview=Vista previa del archivo
+rag.tree.chat.select=Añadir al chat
+rag.tree.chat.deselect=Eliminar del chat
+rag.tree.chat.selected={0} archivo(s) seleccionado(s)
+rag.tree.chat.clear=Limpiar
+rag.tree.chat.add=Añadir al chat
+
+# File Viewer Pane
+file.viewer.loading=Cargando...
+file.viewer.lines={0} líneas
+file.viewer.copy=Copiar contenido
+file.viewer.close=Cerrar visor
+file.viewer.open.external=Abrir externamente
+file.viewer.binary=Archivo binario — no se puede previsualizar como texto.
+file.viewer.too.large=El archivo es demasiado grande para previsualizarlo ({0} KB). El máximo es 512 KB.
+file.viewer.error=No se pudo leer el archivo: {0}
+file.viewer.select.prompt=Selecciona un archivo del árbol superior para previsualizar su contenido
 
 # Project Side Panel
 panel.tab.rag.sources=Fuentes RAG
diff --git a/desktop-shared/src/main/resources/i18n/messages_fr.properties b/desktop-shared/src/main/resources/i18n/messages_fr.properties
index cf139582..806e9146 100644
--- a/desktop-shared/src/main/resources/i18n/messages_fr.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_fr.properties
@@ -487,6 +487,11 @@ chat.tools.button.disabled=Outils disponibles ({0} désactivés)
 chat.input.placeholder=Tapez votre message... (Entrée pour envoyer, Shift+Entrée pour une nouvelle ligne)
 chat.select.file=Sélectionner un ou plusieurs fichiers
 chat.attachment.remove=Supprimer la pièce jointe
+chat.attachment.preview.loading=Chargement de l'aperçu…
+chat.attachment.preview.file.not.found=(Fichier introuvable)
+chat.attachment.preview.too.large=(Fichier trop volumineux pour l'aperçu)
+chat.attachment.preview.cannot.read=(Impossible de lire le fichier : {0})
+chat.attachment.preview.more.lines={0} lignes supplémentaires
 
 # Sessions View
 sessions.title=Sessions de conversation
@@ -876,7 +881,6 @@ knowledge.source.type.url=URL (contenu web)
 # MCP Server Management
 mcp.servers.title=Modèles de serveurs MCP
 mcp.servers.description=Gérez des modèles de serveurs Model Context Protocol pouvant être réutilisés entre plusieurs projets
-mcp.servers.add=Ajouter un modèle de serveur
 mcp.servers.edit=Modifier le modèle
 mcp.servers.delete=Supprimer le modèle
 mcp.servers.delete.confirm.title=Supprimer le modèle de serveur MCP ?
@@ -1100,6 +1104,23 @@ rag.tree.file.copy.path=Copier le chemin
 rag.tree.url.open=Ouvrir dans le navigateur
 rag.tree.url.copy=Copier l’URL
 rag.tree.remove=Supprimer le matériel de référence
+rag.tree.file.preview=Aperçu du fichier
+rag.tree.chat.select=Ajouter au chat
+rag.tree.chat.deselect=Retirer du chat
+rag.tree.chat.selected={0} fichier(s) sélectionné(s)
+rag.tree.chat.clear=Effacer
+rag.tree.chat.add=Ajouter au chat
+
+# File Viewer Pane
+file.viewer.loading=Chargement...
+file.viewer.lines={0} lignes
+file.viewer.copy=Copier le contenu
+file.viewer.close=Fermer la visionneuse
+file.viewer.open.external=Ouvrir en externe
+file.viewer.binary=Fichier binaire — impossible de prévisualiser sous forme de texte.
+file.viewer.too.large=Le fichier est trop volumineux pour être prévisualisé ({0} KB). Le maximum est de 512 KB.
+file.viewer.error=Impossible de lire le fichier : {0}
+file.viewer.select.prompt=Sélectionnez un fichier dans l'arborescence ci-dessus pour prévisualiser son contenu
 
 # Project Side Panel
 panel.tab.rag.sources=Sources RAG
diff --git a/desktop-shared/src/main/resources/i18n/messages_ja_JP.properties b/desktop-shared/src/main/resources/i18n/messages_ja_JP.properties
index 0b0adf9c..ff06de7b 100644
--- a/desktop-shared/src/main/resources/i18n/messages_ja_JP.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_ja_JP.properties
@@ -487,6 +487,11 @@ chat.tools.button.disabled=利用可能なツール（{0} 無効）
 chat.input.placeholder=メッセージを入力...（Enter 送信、Shift+Enter 改行）
 chat.select.file=ファイルを選択（複数可）
 chat.attachment.remove=添付ファイルを削除
+chat.attachment.preview.loading=プレビューを読み込み中…
+chat.attachment.preview.file.not.found=(ファイルが見つかりません)
+chat.attachment.preview.too.large=(ファイルが大きすぎてプレビューできません)
+chat.attachment.preview.cannot.read=(ファイルを読み込めません: {0})
+chat.attachment.preview.more.lines=さらに {0} 行
 
 # Sessions View
 sessions.title=チャットセッション
@@ -876,7 +881,6 @@ knowledge.source.type.url=URL（ウェブコンテンツ）
 # MCP Server Management
 mcp.servers.title=MCP サーバーテンプレート
 mcp.servers.description=プロジェクト全体で使用できる Model Context Protocol サーバーテンプレートを管理します
-mcp.servers.add=サーバーテンプレートを追加
 mcp.servers.edit=テンプレートを編集
 mcp.servers.delete=テンプレートを削除
 mcp.servers.delete.confirm.title=MCP サーバーテンプレートを削除しますか？
@@ -1100,6 +1104,23 @@ rag.tree.file.copy.path=パスをコピー
 rag.tree.url.open=ブラウザで開く
 rag.tree.url.copy=URLをコピー
 rag.tree.remove=参照資料を削除
+rag.tree.file.preview=ファイルのプレビュー
+rag.tree.chat.select=チャットに追加
+rag.tree.chat.deselect=チャットから削除
+rag.tree.chat.selected={0} 個のファイルを選択中
+rag.tree.chat.clear=クリア
+rag.tree.chat.add=チャットに追加
+
+# File Viewer Pane
+file.viewer.loading=読み込み中...
+file.viewer.lines={0} 行
+file.viewer.copy=コンテンツをコピー
+file.viewer.close=ビューアーを閉じる
+file.viewer.open.external=外部で開く
+file.viewer.binary=バイナリファイル — テキストとしてプレビューできません。
+file.viewer.too.large=ファイルが大きすぎてプレビューできません（{0} KB）。最大サイズは 512 KB です。
+file.viewer.error=ファイルを読み込めませんでした: {0}
+file.viewer.select.prompt=上のツリーからファイルを選択して内容をプレビューします
 
 # Project Side Panel
 panel.tab.rag.sources=RAGソース
diff --git a/desktop-shared/src/main/resources/i18n/messages_ko_KR.properties b/desktop-shared/src/main/resources/i18n/messages_ko_KR.properties
index 1ca44188..fa1b9bee 100644
--- a/desktop-shared/src/main/resources/i18n/messages_ko_KR.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_ko_KR.properties
@@ -488,6 +488,11 @@ chat.tools.button.disabled=사용 가능한 도구 ({0} 비활성화됨)
 chat.input.placeholder=메시지 입력... (Enter 전송, Shift+Enter 줄바꿈)
 chat.select.file=파일 선택 (여러 개 선택 가능)
 chat.attachment.remove=첨부 파일 삭제
+chat.attachment.preview.loading=미리보기 불러오는 중…
+chat.attachment.preview.file.not.found=(파일을 찾을 수 없음)
+chat.attachment.preview.too.large=(파일이 너무 커서 미리볼 수 없음)
+chat.attachment.preview.cannot.read=(파일을 읽을 수 없음: {0})
+chat.attachment.preview.more.lines={0}줄 더
 
 # Sessions View
 sessions.title=채팅 세션
@@ -876,7 +881,6 @@ knowledge.source.type.url=URL (웹 콘텐츠)
 # MCP Server Management
 mcp.servers.title=MCP 서버 템플릿
 mcp.servers.description=프로젝트 전반에서 재사용할 수 있는 Model Context Protocol 서버 템플릿을 관리합니다
-mcp.servers.add=서버 템플릿 추가
 mcp.servers.edit=템플릿 편집
 mcp.servers.delete=템플릿 삭제
 mcp.servers.delete.confirm.title=MCP 서버 템플릿을 삭제할까요?
@@ -1100,6 +1104,23 @@ rag.tree.file.copy.path=경로 복사
 rag.tree.url.open=브라우저에서 열기
 rag.tree.url.copy=URL 복사
 rag.tree.remove=참고 자료 삭제
+rag.tree.file.preview=파일 미리보기
+rag.tree.chat.select=채팅에 추가
+rag.tree.chat.deselect=채팅에서 제거
+rag.tree.chat.selected={0}개의 파일 선택됨
+rag.tree.chat.clear=지우기
+rag.tree.chat.add=채팅에 추가
+
+# File Viewer Pane
+file.viewer.loading=로딩 중...
+file.viewer.lines={0}줄
+file.viewer.copy=내용 복사
+file.viewer.close=뷰어 닫기
+file.viewer.open.external=외부에서 열기
+file.viewer.binary=바이너리 파일 — 텍스트로 미리 볼 수 없습니다.
+file.viewer.too.large=파일이 너무 커서 미리 볼 수 없습니다({0} KB). 최대 크기는 512 KB입니다.
+file.viewer.error=파일을 읽을 수 없습니다: {0}
+file.viewer.select.prompt=위 트리에서 파일을 선택하여 내용을 미리 보세요
 
 # Project Side Panel
 panel.tab.rag.sources=RAG 소스
diff --git a/desktop-shared/src/main/resources/i18n/messages_pt_BR.properties b/desktop-shared/src/main/resources/i18n/messages_pt_BR.properties
index ecd72e8e..7a772bc1 100644
--- a/desktop-shared/src/main/resources/i18n/messages_pt_BR.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_pt_BR.properties
@@ -488,6 +488,11 @@ chat.tools.button.disabled=Ferramentas disponíveis ({0} desativadas)
 chat.input.placeholder=Digite sua mensagem... (Enter para enviar, Shift+Enter para nova linha)
 chat.select.file=Selecionar Arquivo(s)
 chat.attachment.remove=Remover anexo
+chat.attachment.preview.loading=Carregando visualização…
+chat.attachment.preview.file.not.found=(Arquivo não encontrado)
+chat.attachment.preview.too.large=(Arquivo muito grande para visualização)
+chat.attachment.preview.cannot.read=(Não é possível ler o arquivo: {0})
+chat.attachment.preview.more.lines=mais {0} linhas
 
 # Sessions View
 sessions.title=Sessões de Conversa
@@ -876,7 +881,6 @@ knowledge.source.type.url=URL (conteúdo da web)
 # MCP Server Management
 mcp.servers.title=Modelos de servidores MCP
 mcp.servers.description=Gerencie modelos de servidores do Model Context Protocol que podem ser reutilizados entre projetos
-mcp.servers.add=Adicionar modelo de servidor
 mcp.servers.edit=Editar modelo
 mcp.servers.delete=Excluir modelo
 mcp.servers.delete.confirm.title=Excluir modelo de servidor MCP?
@@ -1100,6 +1104,23 @@ rag.tree.file.copy.path=Copiar caminho
 rag.tree.url.open=Abrir no navegador
 rag.tree.url.copy=Copiar URL
 rag.tree.remove=Remover material de referência
+rag.tree.file.preview=Visualizar arquivo
+rag.tree.chat.select=Adicionar ao chat
+rag.tree.chat.deselect=Remover do chat
+rag.tree.chat.selected={0} arquivo(s) selecionado(s)
+rag.tree.chat.clear=Limpar
+rag.tree.chat.add=Adicionar ao chat
+
+# File Viewer Pane
+file.viewer.loading=Carregando...
+file.viewer.lines={0} linhas
+file.viewer.copy=Copiar conteúdo
+file.viewer.close=Fechar visualizador
+file.viewer.open.external=Abrir externamente
+file.viewer.binary=Arquivo binário — não é possível visualizar como texto.
+file.viewer.too.large=O arquivo é muito grande para visualização ({0} KB). O máximo é 512 KB.
+file.viewer.error=Não foi possível ler o arquivo: {0}
+file.viewer.select.prompt=Selecione um arquivo na árvore acima para visualizar seu conteúdo
 
 # Project Side Panel
 panel.tab.rag.sources=Fontes RAG
diff --git a/desktop-shared/src/main/resources/i18n/messages_vi_VN.properties b/desktop-shared/src/main/resources/i18n/messages_vi_VN.properties
index 6f264915..79b7c070 100644
--- a/desktop-shared/src/main/resources/i18n/messages_vi_VN.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_vi_VN.properties
@@ -484,6 +484,11 @@ chat.tools.button.disabled=Công cụ khả dụng ({0} bị vô hiệu hóa)
 chat.input.placeholder=Nhập tin nhắn... (Enter để gửi, Shift+Enter để xuống dòng)
 chat.select.file=Chọn tệp (nhiều tệp)
 chat.attachment.remove=Xóa tệp đính kèm
+chat.attachment.preview.loading=Đang tải bản xem trước…
+chat.attachment.preview.file.not.found=(Không tìm thấy tệp)
+chat.attachment.preview.too.large=(Tệp quá lớn để xem trước)
+chat.attachment.preview.cannot.read=(Không thể đọc tệp: {0})
+chat.attachment.preview.more.lines=thêm {0} dòng
 
 # Sessions View
 sessions.title=Các phiên trò chuyện
@@ -875,7 +880,6 @@ knowledge.source.type.url=URL (nội dung web)
 # MCP Server Management
 mcp.servers.title=Mẫu máy chủ MCP
 mcp.servers.description=Quản lý các mẫu máy chủ Model Context Protocol có thể tái sử dụng trên nhiều dự án
-mcp.servers.add=Thêm mẫu máy chủ
 mcp.servers.edit=Chỉnh sửa mẫu
 mcp.servers.delete=Xóa mẫu
 mcp.servers.delete.confirm.title=Xóa mẫu máy chủ MCP?
@@ -1099,6 +1103,23 @@ rag.tree.file.copy.path=Sao chép đường dẫn
 rag.tree.url.open=Mở trong trình duyệt
 rag.tree.url.copy=Sao chép URL
 rag.tree.remove=Xóa tài liệu tham khảo
+rag.tree.file.preview=Xem trước tệp
+rag.tree.chat.select=Thêm vào Chat
+rag.tree.chat.deselect=Xóa khỏi Chat
+rag.tree.chat.selected=Đã chọn {0} tệp
+rag.tree.chat.clear=Xóa
+rag.tree.chat.add=Thêm vào Chat
+
+# File Viewer Pane
+file.viewer.loading=Đang tải...
+file.viewer.lines={0} dòng
+file.viewer.copy=Sao chép nội dung
+file.viewer.close=Đóng trình xem
+file.viewer.open.external=Mở bên ngoài
+file.viewer.binary=Tệp nhị phân — không thể xem trước dưới dạng văn bản.
+file.viewer.too.large=Tệp quá lớn để xem trước ({0} KB). Tối đa là 512 KB.
+file.viewer.error=Không thể đọc tệp: {0}
+file.viewer.select.prompt=Chọn một tệp từ cây bên trên để xem trước nội dung
 
 # Project Side Panel
 panel.tab.rag.sources=Nguồn RAG
diff --git a/desktop-shared/src/main/resources/i18n/messages_zh_CN.properties b/desktop-shared/src/main/resources/i18n/messages_zh_CN.properties
index 215dca4b..8f77b28e 100644
--- a/desktop-shared/src/main/resources/i18n/messages_zh_CN.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_zh_CN.properties
@@ -488,6 +488,11 @@ chat.tools.button.disabled=可用工具（{0} 已禁用）
 chat.input.placeholder=输入消息...（Enter 发送，Shift+Enter 换行）
 chat.select.file=选择文件（可多选）
 chat.attachment.remove=移除附件
+chat.attachment.preview.loading=正在加载预览…
+chat.attachment.preview.file.not.found=(找不到文件)
+chat.attachment.preview.too.large=(文件太大，无法预览)
+chat.attachment.preview.cannot.read=(无法读取文件：{0})
+chat.attachment.preview.more.lines=还有 {0} 行
 
 # Sessions View
 sessions.title=聊天会话
@@ -877,7 +882,6 @@ knowledge.source.type.url=URL（网页内容）
 # MCP Server Management
 mcp.servers.title=MCP 服务器模板
 mcp.servers.description=管理可在多个项目中复用的 Model Context Protocol 服务器模板
-mcp.servers.add=添加服务器模板
 mcp.servers.edit=编辑模板
 mcp.servers.delete=删除模板
 mcp.servers.delete.confirm.title=删除 MCP 服务器模板？
@@ -1101,6 +1105,23 @@ rag.tree.file.copy.path=复制路径
 rag.tree.url.open=在浏览器中打开
 rag.tree.url.copy=复制 URL
 rag.tree.remove=删除参考资料
+rag.tree.file.preview=预览文件
+rag.tree.chat.select=添加到聊天
+rag.tree.chat.deselect=从聊天中移除
+rag.tree.chat.selected=已选择 {0} 个文件
+rag.tree.chat.clear=清除
+rag.tree.chat.add=添加到聊天
+
+# File Viewer Pane
+file.viewer.loading=加载中...
+file.viewer.lines={0} 行
+file.viewer.copy=复制内容
+file.viewer.close=关闭查看器
+file.viewer.open.external=在外部打开
+file.viewer.binary=二进制文件 — 无法作为文本预览。
+file.viewer.too.large=文件太大，无法预览 ({0} KB)。最大为 512 KB。
+file.viewer.error=无法读取文件：{0}
+file.viewer.select.prompt=从上方的树中选择一个文件以预览其内容
 
 # Project Side Panel
 panel.tab.rag.sources=RAG 来源
diff --git a/desktop-shared/src/main/resources/i18n/messages_zh_TW.properties b/desktop-shared/src/main/resources/i18n/messages_zh_TW.properties
index f4d99cde..fc1cab5b 100644
--- a/desktop-shared/src/main/resources/i18n/messages_zh_TW.properties
+++ b/desktop-shared/src/main/resources/i18n/messages_zh_TW.properties
@@ -487,6 +487,11 @@ chat.tools.button.disabled=可用工具（{0} 已停用）
 chat.input.placeholder=輸入訊息...（Enter 送出，Shift+Enter 換行）
 chat.select.file=選擇檔案（可多選）
 chat.attachment.remove=移除附件
+chat.attachment.preview.loading=正在載入預覽…
+chat.attachment.preview.file.not.found=(找不到檔案)
+chat.attachment.preview.too.large=(檔案太大，無法預覽)
+chat.attachment.preview.cannot.read=(無法讀取檔案：{0})
+chat.attachment.preview.more.lines=還有 {0} 行
 
 # Sessions View
 sessions.title=對話工作階段
@@ -878,7 +883,6 @@ knowledge.source.type.url=URL（網頁內容）
 # MCP Server Management
 mcp.servers.title=MCP 伺服器範本
 mcp.servers.description=管理可在多個專案中重複使用的 Model Context Protocol 伺服器範本
-mcp.servers.add=新增伺服器範本
 mcp.servers.edit=編輯範本
 mcp.servers.delete=刪除範本
 mcp.servers.delete.confirm.title=刪除 MCP 伺服器範本？
@@ -1102,6 +1106,23 @@ rag.tree.file.copy.path=複製路徑
 rag.tree.url.open=在瀏覽器中開啟
 rag.tree.url.copy=複製 URL
 rag.tree.remove=刪除參考資料
+rag.tree.file.preview=預覽檔案
+rag.tree.chat.select=新增至聊天
+rag.tree.chat.deselect=從聊天中移除
+rag.tree.chat.selected=已選取 {0} 個檔案
+rag.tree.chat.clear=清除
+rag.tree.chat.add=新增至聊天
+
+# File Viewer Pane
+file.viewer.loading=載入中...
+file.viewer.lines={0} 行
+file.viewer.copy=複製內容
+file.viewer.close=關閉檢視器
+file.viewer.open.external=在外部打開
+file.viewer.binary=二進位檔案 — 無法作為文字預覽。
+file.viewer.too.large=檔案太大，無法預覽 ({0} KB)。最大為 512 KB。
+file.viewer.error=無法讀取檔案：{0}
+file.viewer.select.prompt=從上方的樹狀結構中選擇一個檔案以預覽其內容
 
 # Project Side Panel
 panel.tab.rag.sources=RAG 來源
diff --git a/desktop/build.gradle.kts b/desktop/build.gradle.kts
index 81f40a96..5f139116 100644
--- a/desktop/build.gradle.kts
+++ b/desktop/build.gradle.kts
@@ -49,8 +49,8 @@ val distPackageVersion = project.version.toString().substringBefore("-")
 
 dependencies {
     implementation(compose.desktop.currentOs)
-    implementation(compose.material3)
-    implementation(compose.materialIconsExtended)
+    implementation(libs.compose.material3)
+    implementation(libs.compose.material.icons.extended)
     implementation(project(":shared"))
     implementation(project(":desktop-shared"))
 
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 91dcd2c5..39093b5d 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -21,6 +21,8 @@ sqlite = "3.51.3.0"
 hikaricp = "7.0.2"
 exposed = "1.2.0"
 compose = "1.10.3"
+compose-material3 = "1.9.0"
+compose-material-icons = "1.7.8"
 coil = "3.4.0"
 koin = "4.2.0"
 jlatexmath = "1.0.7"
@@ -71,6 +73,10 @@ jediterm-core = { module = "org.jetbrains.jediterm:jediterm-core", version.ref =
 coil-compose = { module = "io.coil-kt.coil3:coil-compose", version.ref = "coil" }
 coil-network-okhttp = { module = "io.coil-kt.coil3:coil-network-okhttp", version.ref = "coil" }
 
+# Compose Material
+compose-material3 = { module = "org.jetbrains.compose.material3:material3", version.ref = "compose-material3" }
+compose-material-icons-extended = { module = "org.jetbrains.compose.material:material-icons-extended", version.ref = "compose-material-icons" }
+
 # Jackson
 jackson-module-kotlin = { module = "com.fasterxml.jackson.module:jackson-module-kotlin", version.ref = "jackson" }
 jackson-dataformat-yaml = { module = "com.fasterxml.jackson.dataformat:jackson-dataformat-yaml", version.ref = "jackson" }
diff --git a/shared/src/main/kotlin/io/askimo/core/chat/util/FileContentExtractor.kt b/shared/src/main/kotlin/io/askimo/core/chat/util/FileContentExtractor.kt
index 27c7adde..0e55e23b 100644
--- a/shared/src/main/kotlin/io/askimo/core/chat/util/FileContentExtractor.kt
+++ b/shared/src/main/kotlin/io/askimo/core/chat/util/FileContentExtractor.kt
@@ -160,6 +160,21 @@ object FileContentExtractor {
         return false
     }
 
+    /**
+     * Check if a file name (without needing the file on disk) refers to a plain-text file.
+     * Uses extension and known config-file names — no MIME detection.
+     * Suitable for UI decisions (e.g. whether to show an inline preview) where the file
+     * may not yet be read.
+     *
+     * @param fileName The file name (basename, with or without path)
+     * @return true if the extension or filename maps to a text/code file
+     */
+    fun isTextFile(fileName: String): Boolean {
+        val ext = FileTypeSupport.getExtension(fileName).lowercase()
+        return ext in (FileTypeSupport.TEXT_EXTENSIONS + FileTypeSupport.CODE_EXTENSIONS) ||
+            fileName.lowercase() in FileTypeSupport.CONFIG_EXTENSIONS
+    }
+
     /**
      * Check if a file is a text-based file where line numbers are meaningful.
      * Returns false for binary formats like PDF, DOCX, etc.