diff --git a/src/renderer/src/components/chat/ChatInputBox.vue b/src/renderer/src/components/chat/ChatInputBox.vue
index 140380027..864b02f3e 100644
--- a/src/renderer/src/components/chat/ChatInputBox.vue
+++ b/src/renderer/src/components/chat/ChatInputBox.vue
@@ -4,8 +4,8 @@
       'w-full overflow-hidden rounded-xl border bg-card/30 shadow-sm backdrop-blur-lg',
       props.maxWidthClass
     ]"
-    @dragover.prevent
-    @drop.prevent="onDrop"
+    @dragover="onDragOver"
+    @drop="onDrop"
   >
     <input ref="fileInput" type="file" class="hidden" multiple @change="files.handleFileSelect" />
 
@@ -83,6 +83,10 @@ import { TextSelection } from '@tiptap/pm/state'
 import { Icon } from '@iconify/vue'
 import type { MessageFile } from '@shared/types/agent-interface'
 import { useI18n } from 'vue-i18n'
+import {
+  buildChatInputWorkspaceReferenceText,
+  getChatInputWorkspaceItemDragData
+} from '@/lib/chatInputWorkspaceReference'
 import { useChatInputMentions } from './composables/useChatInputMentions'
 import { useChatInputFiles } from './composables/useChatInputFiles'
 import { useSkillsData } from '@/components/chat-input/composables/useSkillsData'
@@ -329,7 +333,44 @@ function onPaste(event: ClipboardEvent) {
   void files.handlePaste(event, true)
 }
 
+function onDragOver(event: DragEvent) {
+  event.preventDefault()
+  if (event.dataTransfer) {
+    event.dataTransfer.dropEffect = 'copy'
+  }
+}
+
+function insertWorkspaceReference(targetPath: string) {
+  const referenceText = buildChatInputWorkspaceReferenceText(
+    targetPath,
+    props.workspacePath,
+    targetPath.split(/[/\\]/).pop()
+  )
+  if (!referenceText) {
+    return false
+  }
+
+  const { from, to } = editor.state.selection
+  const docSize = editor.state.doc.content.size
+  const before =
+    from > 0 ? editor.state.doc.textBetween(Math.max(0, from - 1), from, '\n', '\n') : ''
+  const after =
+    to < docSize ? editor.state.doc.textBetween(to, Math.min(docSize, to + 1), '\n', '\n') : ''
+  const prefix = before && !/\s/.test(before) ? ' ' : ''
+  const suffix = after && /\s/.test(after) ? '' : ' '
+
+  editor.chain().focus().insertContent(`${prefix}${referenceText}${suffix}`).run()
+  return true
+}
+
 function onDrop(event: DragEvent) {
+  event.preventDefault()
+
+  const workspaceItem = getChatInputWorkspaceItemDragData(event.dataTransfer)
+  if (workspaceItem && insertWorkspaceReference(workspaceItem.path)) {
+    return
+  }
+
   if (!event.dataTransfer?.files || event.dataTransfer.files.length === 0) {
     return
   }
diff --git a/src/renderer/src/components/chat/composables/useChatInputMentions.ts b/src/renderer/src/components/chat/composables/useChatInputMentions.ts
index 849a9f763..92f1de34a 100644
--- a/src/renderer/src/components/chat/composables/useChatInputMentions.ts
+++ b/src/renderer/src/components/chat/composables/useChatInputMentions.ts
@@ -7,6 +7,10 @@ import { ACP_WORKSPACE_EVENTS } from '@/events'
 import { usePresenter } from '@/composables/usePresenter'
 import { useMcpStore } from '@/stores/mcp'
 import { useSkillsStore } from '@/stores/skillsStore'
+import {
+  buildChatInputWorkspaceReferenceText,
+  resolveChatInputWorkspaceReferencePath
+} from '@/lib/chatInputWorkspaceReference'
 import SuggestionList from '../mentions/SuggestionList.vue'
 import {
   buildCommandText,
@@ -154,8 +158,11 @@ export function useChatInputMentions(options: UseChatInputMentionsOptions) {
         ([] as WorkspaceFileNode[])
 
       return result.slice(0, 20).map((file) => {
-        const relativePath = window.api.toRelativePath?.(file.path, workspacePath) ?? ''
-        const displayPath = relativePath || file.name
+        const displayPath = resolveChatInputWorkspaceReferencePath(
+          file.path,
+          workspacePath,
+          file.name
+        )
         return {
           id: `file:${file.path}`,
           category: 'file' as const,
@@ -163,7 +170,7 @@ export function useChatInputMentions(options: UseChatInputMentionsOptions) {
           description: file.path,
           payload: {
             path: file.path,
-            insertText: `@${displayPath} `
+            insertText: `${buildChatInputWorkspaceReferenceText(file.path, workspacePath, file.name)} `
           }
         }
       })
diff --git a/src/renderer/src/components/workspace/WorkspaceFileNode.vue b/src/renderer/src/components/workspace/WorkspaceFileNode.vue
index 3f32d365f..1e46ce67d 100644
--- a/src/renderer/src/components/workspace/WorkspaceFileNode.vue
+++ b/src/renderer/src/components/workspace/WorkspaceFileNode.vue
@@ -3,10 +3,12 @@
     <ContextMenu>
       <ContextMenuTrigger as-child>
         <button
-          class="flex w-full items-center gap-1.5 px-4 py-1 text-left text-xs transition hover:bg-muted/40"
+          class="flex w-full cursor-grab items-center gap-1.5 px-4 py-1 text-left text-xs transition hover:bg-muted/40 active:cursor-grabbing"
           :style="{ paddingLeft: `${16 + depth * 12}px` }"
           type="button"
+          draggable="true"
           @click="handleClick"
+          @dragstart="handleDragStart"
         >
           <!-- Expand/collapse icon for directories -->
           <Icon
@@ -62,6 +64,7 @@ import { computed } from 'vue'
 import { Icon } from '@iconify/vue'
 import { useI18n } from 'vue-i18n'
 import { usePresenter } from '@/composables/usePresenter'
+import { setChatInputWorkspaceItemDragData } from '@/lib/chatInputWorkspaceReference'
 import {
   ContextMenu,
   ContextMenuContent,
@@ -156,6 +159,13 @@ const handleRevealInFolder = async () => {
 const handleAppendFromMenu = () => {
   emitAppendPath()
 }
+
+const handleDragStart = (event: DragEvent) => {
+  setChatInputWorkspaceItemDragData(event.dataTransfer, {
+    path: props.node.path,
+    isDirectory: props.node.isDirectory
+  })
+}
 </script>
 
 <style scoped>
diff --git a/src/renderer/src/lib/chatInputWorkspaceReference.ts b/src/renderer/src/lib/chatInputWorkspaceReference.ts
new file mode 100644
index 000000000..23d55d098
--- /dev/null
+++ b/src/renderer/src/lib/chatInputWorkspaceReference.ts
@@ -0,0 +1,123 @@
+export const CHAT_INPUT_WORKSPACE_ITEM_MIME = 'application/x-deepchat-workspace-item'
+
+export interface ChatInputWorkspaceItemDragPayload {
+  path: string
+  isDirectory: boolean
+}
+
+const isRecord = (value: unknown): value is Record<string, unknown> => {
+  return typeof value === 'object' && value !== null
+}
+
+const normalizeTrimmedString = (value: unknown): string => {
+  return typeof value === 'string' ? value.trim() : ''
+}
+
+const resolveRelativePathFallback = (targetPath: string, workspacePath: string): string => {
+  const normalizedTarget = targetPath.replace(/\\/g, '/')
+  const normalizedWorkspace = workspacePath.replace(/\\/g, '/').replace(/\/+$/, '')
+
+  if (!normalizedWorkspace) {
+    return targetPath
+  }
+
+  if (normalizedTarget === normalizedWorkspace) {
+    return ''
+  }
+
+  const expectedPrefix = `${normalizedWorkspace}/`
+  if (!normalizedTarget.startsWith(expectedPrefix)) {
+    return targetPath
+  }
+
+  return normalizedTarget.slice(expectedPrefix.length)
+}
+
+export const setChatInputWorkspaceItemDragData = (
+  dataTransfer: DataTransfer | null | undefined,
+  payload: ChatInputWorkspaceItemDragPayload
+) => {
+  const path = normalizeTrimmedString(payload.path)
+  if (!dataTransfer || !path) {
+    return
+  }
+
+  dataTransfer.setData(
+    CHAT_INPUT_WORKSPACE_ITEM_MIME,
+    JSON.stringify({
+      path,
+      isDirectory: Boolean(payload.isDirectory)
+    })
+  )
+  dataTransfer.effectAllowed = 'copy'
+}
+
+export const getChatInputWorkspaceItemDragData = (
+  dataTransfer: DataTransfer | null | undefined
+): ChatInputWorkspaceItemDragPayload | null => {
+  const dragTypes = dataTransfer?.types ? Array.from(dataTransfer.types) : []
+  if (!dragTypes.includes(CHAT_INPUT_WORKSPACE_ITEM_MIME)) {
+    return null
+  }
+
+  try {
+    const raw = dataTransfer?.getData(CHAT_INPUT_WORKSPACE_ITEM_MIME)
+    const parsed = JSON.parse(raw || '{}') as unknown
+    if (!isRecord(parsed)) {
+      return null
+    }
+
+    const path = normalizeTrimmedString(parsed.path)
+    if (!path) {
+      return null
+    }
+
+    return {
+      path,
+      isDirectory: Boolean(parsed.isDirectory)
+    }
+  } catch (error) {
+    console.warn('[ChatInputWorkspaceReference] Failed to parse drag payload:', error)
+    return null
+  }
+}
+
+export const resolveChatInputWorkspaceReferencePath = (
+  targetPath: string,
+  workspacePath?: string | null,
+  fallbackName?: string | null
+): string => {
+  const normalizedTargetPath = normalizeTrimmedString(targetPath)
+  const normalizedFallbackName = normalizeTrimmedString(fallbackName)
+  if (!normalizedTargetPath) {
+    return normalizedFallbackName
+  }
+
+  const normalizedWorkspacePath = normalizeTrimmedString(workspacePath)
+  if (!normalizedWorkspacePath) {
+    return normalizedFallbackName || normalizedTargetPath
+  }
+
+  const relativePath =
+    window.api?.toRelativePath?.(normalizedTargetPath, normalizedWorkspacePath) ??
+    resolveRelativePathFallback(normalizedTargetPath, normalizedWorkspacePath)
+  const normalizedRelativePath = normalizeTrimmedString(relativePath)
+  if (normalizedRelativePath && normalizedRelativePath !== '.') {
+    return normalizedRelativePath
+  }
+
+  return normalizedFallbackName || normalizedTargetPath
+}
+
+export const buildChatInputWorkspaceReferenceText = (
+  targetPath: string,
+  workspacePath?: string | null,
+  fallbackName?: string | null
+): string => {
+  const referencePath = resolveChatInputWorkspaceReferencePath(
+    targetPath,
+    workspacePath,
+    fallbackName
+  )
+  return referencePath ? `@${referencePath}` : ''
+}
diff --git a/test/renderer/components/ChatInputBox.test.ts b/test/renderer/components/ChatInputBox.test.ts
index 5f7f9388f..efb1b5ae3 100644
--- a/test/renderer/components/ChatInputBox.test.ts
+++ b/test/renderer/components/ChatInputBox.test.ts
@@ -1,11 +1,13 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest'
 import { mount } from '@vue/test-utils'
 import { defineComponent, ref, nextTick } from 'vue'
+import { CHAT_INPUT_WORKSPACE_ITEM_MIME } from '@/lib/chatInputWorkspaceReference'
 
 const handlePasteMock = vi.fn().mockResolvedValue(undefined)
 const handleDropMock = vi.fn().mockResolvedValue(undefined)
 const openFilePickerMock = vi.fn()
 const deleteFileMock = vi.fn()
+const insertContentMock = vi.fn()
 const selectedFilesRef = ref<any[]>([])
 const activeSkillsRef = ref<string[]>([])
 const pendingSkillsRef = ref<string[]>([])
@@ -25,13 +27,23 @@ vi.mock('@tiptap/vue-3', () => {
       setContent: vi.fn()
     }
     public state = {
-      doc: {},
+      doc: {
+        content: {
+          size: 0
+        },
+        textBetween: vi.fn(() => '')
+      },
+      selection: {
+        from: 0,
+        to: 0
+      },
       tr: {
         setSelection: vi.fn()
       }
     }
     public view = {
-      dispatch: vi.fn()
+      dispatch: vi.fn(),
+      updateState: vi.fn()
     }
     constructor(options: any) {
       lastEditorOptions = options
@@ -40,13 +52,22 @@ vi.mock('@tiptap/vue-3', () => {
       return ''
     }
     chain() {
-      return {
+      const api = {
+        focus: () => api,
+        insertContent: (content: string) => {
+          insertContentMock(content)
+          return api
+        },
+        run: () => true,
         setHardBreak: () => ({
           scrollIntoView: () => ({
             run: () => true
           })
         })
       }
+      return {
+        ...api
+      }
     }
     destroy() {}
   }
@@ -195,6 +216,27 @@ describe('ChatInputBox attachments', () => {
     expect(handleDropMock).toHaveBeenCalledWith(files)
   })
 
+  it('inserts workspace references for internal workspace drops', async () => {
+    const wrapper = await mountComponent()
+    const dataTransfer = {
+      types: [CHAT_INPUT_WORKSPACE_ITEM_MIME],
+      getData: vi.fn(() =>
+        JSON.stringify({
+          path: '/repo/src/App.vue',
+          isDirectory: false
+        })
+      )
+    } as unknown as DataTransfer
+
+    await wrapper.setProps({
+      workspacePath: '/repo'
+    })
+    await wrapper.trigger('drop', { dataTransfer })
+
+    expect(insertContentMock).toHaveBeenCalledWith('@src/App.vue ')
+    expect(handleDropMock).not.toHaveBeenCalled()
+  })
+
   it('handles remove attached file', async () => {
     const wrapper = await mountComponent({
       files: [{ name: 'a.txt', path: '/tmp/a.txt' }]
diff --git a/test/renderer/components/WorkspaceFileNode.test.ts b/test/renderer/components/WorkspaceFileNode.test.ts
new file mode 100644
index 000000000..f192588bb
--- /dev/null
+++ b/test/renderer/components/WorkspaceFileNode.test.ts
@@ -0,0 +1,75 @@
+import { describe, expect, it, vi } from 'vitest'
+import { mount } from '@vue/test-utils'
+import { defineComponent } from 'vue'
+import WorkspaceFileNode from '@/components/workspace/WorkspaceFileNode.vue'
+import { CHAT_INPUT_WORKSPACE_ITEM_MIME } from '@/lib/chatInputWorkspaceReference'
+
+vi.mock('vue-i18n', () => ({
+  useI18n: () => ({
+    t: (key: string) => key
+  })
+}))
+
+vi.mock('@iconify/vue', () => ({
+  Icon: defineComponent({
+    name: 'Icon',
+    template: '<i class="icon-stub" />'
+  })
+}))
+
+vi.mock('@/composables/usePresenter', () => ({
+  usePresenter: () => ({
+    openFile: vi.fn(),
+    revealFileInFolder: vi.fn()
+  })
+}))
+
+describe('WorkspaceFileNode drag support', () => {
+  it('writes workspace drag payload on dragstart', async () => {
+    const wrapper = mount(WorkspaceFileNode, {
+      props: {
+        node: {
+          name: 'App.vue',
+          path: '/repo/src/App.vue',
+          isDirectory: false
+        },
+        depth: 0
+      },
+      global: {
+        stubs: {
+          ContextMenu: defineComponent({
+            template: '<div><slot /></div>'
+          }),
+          ContextMenuTrigger: defineComponent({
+            template: '<div><slot /></div>'
+          }),
+          ContextMenuContent: defineComponent({
+            template: '<div><slot /></div>'
+          }),
+          ContextMenuItem: defineComponent({
+            template: '<button type="button"><slot /></button>'
+          }),
+          ContextMenuSeparator: defineComponent({
+            template: '<div />'
+          })
+        }
+      }
+    })
+
+    const dataTransfer = {
+      setData: vi.fn(),
+      effectAllowed: 'all'
+    } as unknown as DataTransfer
+
+    await wrapper.get('button[draggable="true"]').trigger('dragstart', { dataTransfer })
+
+    expect((dataTransfer as any).setData).toHaveBeenCalledWith(
+      CHAT_INPUT_WORKSPACE_ITEM_MIME,
+      JSON.stringify({
+        path: '/repo/src/App.vue',
+        isDirectory: false
+      })
+    )
+    expect((dataTransfer as any).effectAllowed).toBe('copy')
+  })
+})