diff --git a/desktop/src/api/sessions.test.ts b/desktop/src/api/sessions.test.ts
index 5a6aee98..ab1fa64d 100644
--- a/desktop/src/api/sessions.test.ts
+++ b/desktop/src/api/sessions.test.ts
@@ -56,4 +56,25 @@ describe('sessionsApi', () => {
     expect(url).toBe('http://127.0.0.1:3456/api/sessions/session-1/trace/calls/call-1')
     expect(init).toMatchObject({ method: 'GET' })
   })
+
+  it('searches the session workspace with an encoded query', async () => {
+    const fetchMock = vi.spyOn(globalThis, 'fetch')
+    fetchMock.mockResolvedValueOnce(new Response(JSON.stringify({
+      state: 'ok',
+      query: 'Mental Health Controller',
+      truncated: false,
+      entries: [],
+    }), {
+      status: 200,
+      headers: { 'Content-Type': 'application/json' },
+    }))
+
+    const result = await sessionsApi.searchWorkspace('session-1', 'Mental Health Controller')
+
+    expect(result.query).toBe('Mental Health Controller')
+    expect(result.truncated).toBe(false)
+    const [url, init] = fetchMock.mock.calls[0]!
+    expect(url).toBe('http://127.0.0.1:3456/api/sessions/session-1/workspace/search?query=Mental+Health+Controller')
+    expect(init).toMatchObject({ method: 'GET' })
+  })
 })
diff --git a/desktop/src/api/sessions.ts b/desktop/src/api/sessions.ts
index 00f3d373..f45f28a1 100644
--- a/desktop/src/api/sessions.ts
+++ b/desktop/src/api/sessions.ts
@@ -270,6 +270,13 @@ export type WorkspaceTreeResult = {
   error?: string
 }
 
+export type WorkspaceSearchResult = {
+  state: 'ok'
+  query: string
+  truncated: boolean
+  entries: WorkspaceTreeEntry[]
+}
+
 export type WorkspaceDiffResult = {
   state: 'ok' | 'missing' | 'not_git_repo' | 'error'
   path: string
@@ -392,6 +399,11 @@ export const sessionsApi = {
     return api.get<WorkspaceTreeResult>(buildWorkspacePath(sessionId, 'tree', workspacePath))
   },
 
+  searchWorkspace(sessionId: string, query: string) {
+    const params = new URLSearchParams({ query })
+    return api.get<WorkspaceSearchResult>(`/api/sessions/${sessionId}/workspace/search?${params}`)
+  },
+
   getWorkspaceFile(sessionId: string, workspacePath: string) {
     return api.get<WorkspaceReadFileResult>(buildWorkspacePath(sessionId, 'file', workspacePath))
   },
diff --git a/desktop/src/components/workspace/WorkspacePanel.test.tsx b/desktop/src/components/workspace/WorkspacePanel.test.tsx
index 28cf93f2..9e67b626 100644
--- a/desktop/src/components/workspace/WorkspacePanel.test.tsx
+++ b/desktop/src/components/workspace/WorkspacePanel.test.tsx
@@ -31,6 +31,7 @@ if (typeof document === 'undefined') {
 type WorkspaceApiMocks = {
   getWorkspaceStatusMock: ReturnType<typeof vi.fn>
   getWorkspaceTreeMock: ReturnType<typeof vi.fn>
+  searchWorkspaceMock: ReturnType<typeof vi.fn>
   getWorkspaceFileMock: ReturnType<typeof vi.fn>
   getWorkspaceDiffMock: ReturnType<typeof vi.fn>
 }
@@ -258,6 +259,7 @@ vi.mock('../../api/sessions', () => ({
       mocks = {
         getWorkspaceStatusMock: vi.fn(),
         getWorkspaceTreeMock: vi.fn(),
+        searchWorkspaceMock: vi.fn(),
         getWorkspaceFileMock: vi.fn(),
         getWorkspaceDiffMock: vi.fn(),
       }
@@ -266,6 +268,7 @@ vi.mock('../../api/sessions', () => ({
     return {
       getWorkspaceStatus: mocks.getWorkspaceStatusMock,
       getWorkspaceTree: mocks.getWorkspaceTreeMock,
+      searchWorkspace: mocks.searchWorkspaceMock,
       getWorkspaceFile: mocks.getWorkspaceFileMock,
       getWorkspaceDiff: mocks.getWorkspaceDiffMock,
     }
@@ -393,7 +396,7 @@ describe('WorkspacePanel', () => {
       await statusRequest.promise
     })
 
-    expect(view.getByPlaceholderText('Filter files...')).toBeTruthy()
+    expect(view.getByPlaceholderText('Filter changed files...')).toBeTruthy()
 
     await waitFor(() => {
       expect(view.container.querySelector('[data-workspace-file-path="src/app.ts"]')).toBeTruthy()
@@ -430,7 +433,7 @@ describe('WorkspacePanel', () => {
     expect(view.queryByTestId('workspace-file-navigator')).toBeNull()
     await clickElement(view.getByRole('button', { name: 'Show file navigator' }))
     expect(view.getByTestId('workspace-file-navigator').className).toContain('absolute')
-    expect(view.queryByTestId('workspace-file-navigator-header')).toBeNull()
+    expect(view.getByTestId('workspace-file-navigator-header')).toBeTruthy()
     expect(view.queryByText('1 file')).toBeNull()
     expect(view.getByTestId('workspace-file-navigator').className).toContain('w-[min(280px,100%)]')
     expect(view.getByTestId('workspace-review-layout').className).toContain('grid-cols-1')
@@ -526,7 +529,7 @@ describe('WorkspacePanel', () => {
     expect(view.queryByText('claude-code-haha')).toBeNull()
     expect(view.queryByText('main')).toBeNull()
 
-    const filter = view.getByPlaceholderText('Filter files...')
+    const filter = view.getByPlaceholderText('Filter changed files...')
     expect(view.queryByText('3 files')).toBeNull()
     fireEvent.change(filter, { target: { value: 'theme' } })
 
@@ -614,7 +617,7 @@ describe('WorkspacePanel', () => {
     expect(view.getByText('App.tsx')).toBeTruthy()
     expect(view.getByText('theme.css')).toBeTruthy()
 
-    fireEvent.change(view.getByPlaceholderText('Filter files...'), { target: { value: 'theme' } })
+    fireEvent.change(view.getByPlaceholderText('Filter changed files...'), { target: { value: 'theme' } })
 
     expect(view.getByText('desktop/src')).toBeTruthy()
     expect(view.queryByText('docs')).toBeNull()
@@ -859,11 +862,224 @@ describe('WorkspacePanel', () => {
     expect(view.queryByRole('status')).toBeNull()
     expect(view.queryByText('No changes')).toBeNull()
 
-    fireEvent.change(view.getByPlaceholderText('Filter files...'), { target: { value: 'readme' } })
+    getMocks().searchWorkspaceMock.mockResolvedValueOnce({
+      state: 'ok',
+      query: 'readme',
+      truncated: false,
+      entries: [{ name: 'README.md', path: 'README.md', isDirectory: false }],
+    })
+    fireEvent.change(view.getByPlaceholderText('Search all files...'), { target: { value: 'readme' } })
 
-    expect(view.getByRole('status').textContent).toBe('1 of 2 items')
-    expect(view.queryByText('src')).toBeNull()
+    expect(await view.findByText('1 search results')).toBeTruthy()
     expect(view.getByText('README.md')).toBeTruthy()
+    expect(view.queryByText('src')).toBeNull()
+  })
+
+  it('searches unopened directories in a deep Java project without expanding the tree first', async () => {
+    const sessionId = 'session-deep-java-search'
+    const targetPath = 'services/mental-health-service/src/main/java/com/example/campus/mentalhealth/controller/MentalHealthTrendController.java'
+
+    getMocks().searchWorkspaceMock.mockResolvedValue({
+      state: 'ok',
+      query: 'MentalHealthTrendController',
+      truncated: false,
+      entries: [{
+        name: 'MentalHealthTrendController.java',
+        path: targetPath,
+        isDirectory: false,
+      }],
+    })
+    getMocks().getWorkspaceFileMock.mockResolvedValue({
+      state: 'ok',
+      path: targetPath,
+      content: 'package com.example.campus;\n\npublic final class MentalHealthTrendController {}\n',
+      language: 'java',
+      size: 82,
+    })
+
+    await setWorkspaceState((state) => ({
+      ...state,
+      panelBySession: {
+        ...state.panelBySession,
+        [sessionId]: { isOpen: true, activeView: 'all', hasUserSelectedView: true },
+      },
+      statusBySession: {
+        ...state.statusBySession,
+        [sessionId]: {
+          state: 'ok',
+          workDir: '/repo/campus-agent-platform',
+          repoName: 'campus-agent-platform',
+          branch: 'main',
+          isGitRepo: true,
+          changedFiles: [],
+        },
+      },
+      treeBySessionPath: {
+        ...state.treeBySessionPath,
+        [sessionId]: {
+          '': {
+            state: 'ok',
+            path: '',
+            entries: [
+              { name: 'identity-domain', path: 'identity-domain', isDirectory: true },
+              { name: 'identity-application', path: 'identity-application', isDirectory: true },
+              { name: 'identity-adapter', path: 'identity-adapter', isDirectory: true },
+              { name: 'services', path: 'services', isDirectory: true },
+              { name: 'build.gradle', path: 'build.gradle', isDirectory: false },
+            ],
+          },
+        },
+      },
+    }))
+
+    const view = await renderPanel(sessionId)
+    fireEvent.change(view.getByPlaceholderText('Search all files...'), {
+      target: { value: 'MentalHealthTrendController' },
+    })
+
+    expect(await view.findByText('MentalHealthTrendController.java')).toBeTruthy()
+    expect(view.getByText('services/mental-health-service/src/main/java/com/example/campus/mentalhealth/controller')).toBeTruthy()
+    expect(view.queryByRole('button', { name: 'services' })).toBeNull()
+    expect(getMocks().searchWorkspaceMock).toHaveBeenCalledWith(sessionId, 'MentalHealthTrendController')
+    expect(getMocks().getWorkspaceTreeMock).not.toHaveBeenCalledWith(sessionId, 'services')
+
+    await clickElement(view.getByRole('button', {
+      name: 'MentalHealthTrendController.java, services/mental-health-service/src/main/java/com/example/campus/mentalhealth/controller',
+    }))
+    expect((await view.findByTestId('workspace-preview-header')).textContent).toContain(targetPath)
+    await waitFor(() => {
+      expect(document.activeElement).toBe(view.getByTestId('workspace-preview-header'))
+    })
+
+    await clickElement(view.getByRole('button', { name: 'Show file navigator' }))
+    const searchInput = view.getByPlaceholderText('Search all files...') as HTMLInputElement
+    expect(searchInput.value).toBe('MentalHealthTrendController')
+    expect(view.getByText('MentalHealthTrendController.java')).toBeTruthy()
+    await waitFor(() => {
+      expect(document.activeElement).toBe(searchInput)
+    })
+
+    const staleSearch = deferred<{
+      state: 'ok'
+      query: string
+      truncated: boolean
+      entries: Array<{ name: string; path: string; isDirectory: boolean }>
+    }>()
+    getMocks().searchWorkspaceMock.mockReset()
+    getMocks().searchWorkspaceMock
+      .mockReturnValueOnce(staleSearch.promise)
+      .mockResolvedValueOnce({
+        state: 'ok',
+        query: 'JdbcOrganizationHierarchyRepository',
+        truncated: false,
+        entries: [{
+          name: 'JdbcOrganizationHierarchyRepository.java',
+          path: 'identity-adapter/src/main/java/com/example/campus/identity/adapter/persistence/mysql/JdbcOrganizationHierarchyRepository.java',
+          isDirectory: false,
+        }, {
+          name: 'JdbcOrganizationHierarchyRepositoryTest.java',
+          path: 'identity-adapter/src/test/java/com/example/campus/identity/adapter/persistence/mysql/JdbcOrganizationHierarchyRepositoryTest.java',
+          isDirectory: false,
+        }],
+      })
+
+    fireEvent.change(view.getByPlaceholderText('Search all files...'), {
+      target: { value: 'DeepOrganizationHierarchySearchService' },
+    })
+    await waitFor(() => {
+      expect(getMocks().searchWorkspaceMock).toHaveBeenCalledWith(sessionId, 'DeepOrganizationHierarchySearchService')
+    })
+    fireEvent.change(view.getByPlaceholderText('Search all files...'), {
+      target: { value: 'JdbcOrganizationHierarchyRepository' },
+    })
+
+    expect(await view.findByText('JdbcOrganizationHierarchyRepository.java')).toBeTruthy()
+    staleSearch.resolve({
+      state: 'ok',
+      query: 'DeepOrganizationHierarchySearchService',
+      truncated: false,
+      entries: [{
+        name: 'DeepOrganizationHierarchySearchService.java',
+        path: 'identity-application/src/main/java/com/example/campus/identity/application/query/DeepOrganizationHierarchySearchService.java',
+        isDirectory: false,
+      }],
+    })
+    await flushReactWork()
+    expect(view.queryByText('DeepOrganizationHierarchySearchService.java')).toBeNull()
+    expect(view.getByText('JdbcOrganizationHierarchyRepository.java')).toBeTruthy()
+
+    const currentSearchInput = view.getByPlaceholderText('Search all files...')
+    fireEvent.keyDown(currentSearchInput, { key: 'ArrowDown' })
+    const currentResult = view.getByRole('button', {
+      name: /JdbcOrganizationHierarchyRepository\.java, identity-adapter\/src\/main/,
+    })
+    expect(document.activeElement).toBe(currentResult)
+    const nextResult = view.getByRole('button', {
+      name: /JdbcOrganizationHierarchyRepositoryTest\.java/,
+    })
+    fireEvent.keyDown(currentResult, { key: 'ArrowDown' })
+    expect(document.activeElement).toBe(nextResult)
+    fireEvent.keyDown(nextResult, { key: 'ArrowUp' })
+    expect(document.activeElement).toBe(currentResult)
+    fireEvent.keyDown(currentResult, { key: 'End' })
+    expect(document.activeElement).toBe(nextResult)
+    fireEvent.keyDown(nextResult, { key: 'Home' })
+    expect(document.activeElement).toBe(currentResult)
+    fireEvent.keyDown(currentResult, { key: 'Escape' })
+    await waitFor(() => {
+      expect(document.activeElement).toBe(currentSearchInput)
+    })
+    expect(view.getByText('services')).toBeTruthy()
+    expect(view.queryByText('JdbcOrganizationHierarchyRepository.java')).toBeNull()
+  })
+
+  it('shows workspace search errors and empty results without falling back to the loaded root tree', async () => {
+    const sessionId = 'session-workspace-search-states'
+    getMocks().searchWorkspaceMock
+      .mockRejectedValueOnce(new Error('Workspace search failed'))
+      .mockResolvedValueOnce({ state: 'ok', query: 'missing-class', truncated: false, entries: [] })
+
+    await setWorkspaceState((state) => ({
+      ...state,
+      panelBySession: {
+        ...state.panelBySession,
+        [sessionId]: { isOpen: true, activeView: 'all', hasUserSelectedView: true },
+      },
+      statusBySession: {
+        ...state.statusBySession,
+        [sessionId]: {
+          state: 'ok',
+          workDir: '/repo/campus-agent-platform',
+          repoName: 'campus-agent-platform',
+          branch: 'main',
+          isGitRepo: true,
+          changedFiles: [],
+        },
+      },
+      treeBySessionPath: {
+        ...state.treeBySessionPath,
+        [sessionId]: {
+          '': {
+            state: 'ok',
+            path: '',
+            entries: [{ name: 'services', path: 'services', isDirectory: true }],
+          },
+        },
+      },
+    }))
+
+    const view = await renderPanel(sessionId)
+    fireEvent.change(view.getByPlaceholderText('Search all files...'), {
+      target: { value: 'broken-search' },
+    })
+    expect(await view.findByText('Workspace search failed')).toBeTruthy()
+    expect(view.queryByText('services')).toBeNull()
+
+    fireEvent.change(view.getByPlaceholderText('Search all files...'), {
+      target: { value: 'missing-class' },
+    })
+    expect(await view.findByText('No matching files')).toBeTruthy()
+    expect(view.queryByText('services')).toBeNull()
   })
 
   it('lazy loads the root tree, expands directories, and opens file previews from the all-files view', async () => {
@@ -1104,17 +1320,17 @@ describe('WorkspacePanel', () => {
 
     expect(view.getByTestId('workspace-code').textContent).toContain('+new')
     expect(view.queryByRole('button', { name: 'Changed files' })).toBeNull()
-    expect(view.queryByPlaceholderText('Filter files...')).toBeNull()
+    expect(view.queryByPlaceholderText('Filter changed files...')).toBeNull()
 
     await clickElement(view.getByRole('button', { name: 'Show file navigator' }))
 
-    expect(view.queryByRole('button', { name: 'Changed files' })).toBeNull()
-    expect(view.getByPlaceholderText('Filter files...')).toBeTruthy()
+    expect(view.getByRole('button', { name: 'Changed files' })).toBeTruthy()
+    expect(view.getByPlaceholderText('Filter changed files...')).toBeTruthy()
     expect(view.container.querySelector('[data-workspace-file-path="src/app.ts"]')).toBeTruthy()
     expect(view.getByRole('button', { name: 'Hide file navigator' })).toBeTruthy()
   })
 
-  it('keeps a preview navigator scoped to changed files when the previous view was all files', async () => {
+  it('preserves the all-files navigator when a preview is already open', async () => {
     getMocks().getWorkspaceTreeMock.mockResolvedValue({
       state: 'ok',
       path: '',
@@ -1172,10 +1388,14 @@ describe('WorkspacePanel', () => {
     expect(getMocks().getWorkspaceTreeMock).not.toHaveBeenCalled()
 
     await clickElement(view.getByRole('button', { name: 'Show file navigator' }))
-    await flushReactWork()
+    await waitFor(() => {
+      expect(getMocks().getWorkspaceTreeMock).toHaveBeenCalledWith('session-preview-hidden-tree', '')
+    })
 
-    expect(getMocks().getWorkspaceTreeMock).not.toHaveBeenCalled()
-    expect(view.container.querySelector('[data-workspace-file-path="src/app.ts"]')).toBeTruthy()
+    expect(view.getByRole('button', { name: 'All files' })).toBeTruthy()
+    expect(view.getByPlaceholderText('Search all files...')).toBeTruthy()
+    expect(view.getByText('src')).toBeTruthy()
+    expect(view.container.querySelector('[data-workspace-file-path="src/app.ts"]')).toBeNull()
   })
 
   it('uses theme tokens for the panel, preview header, and code surface in dark mode', async () => {
@@ -1237,6 +1457,74 @@ describe('WorkspacePanel', () => {
     expect(classNameContains(codeSurface, 'bg-white')).toBe(false)
   })
 
+  it('syntax highlights Java source previews instead of rendering them as plain text', async () => {
+    const sessionId = 'session-java-preview'
+    const javaSource = [
+      'package com.example.campus;',
+      '',
+      'import java.util.List;',
+      '',
+      'public final class MentalHealthTrendController {',
+      '  private final List<String> campusIds;',
+      '',
+      '  public int countVisibleOrganizations() {',
+      '    return campusIds.size();',
+      '  }',
+      '}',
+    ].join('\n')
+
+    await setWorkspaceState((state) => ({
+      ...state,
+      panelBySession: {
+        ...state.panelBySession,
+        [sessionId]: {
+          isOpen: true,
+          activeView: 'all',
+          hasUserSelectedView: true,
+        },
+      },
+      statusBySession: {
+        ...state.statusBySession,
+        [sessionId]: {
+          state: 'ok',
+          workDir: '/repo',
+          repoName: 'repo',
+          branch: 'main',
+          isGitRepo: true,
+          changedFiles: [],
+        },
+      },
+      previewTabsBySession: {
+        ...state.previewTabsBySession,
+        [sessionId]: [{
+          id: 'file:src/MentalHealthTrendController.java',
+          path: 'src/MentalHealthTrendController.java',
+          kind: 'file',
+          title: 'MentalHealthTrendController.java',
+          language: 'java',
+          content: javaSource,
+          state: 'ok',
+          size: javaSource.length,
+        }],
+      },
+      activePreviewTabIdBySession: {
+        ...state.activePreviewTabIdBySession,
+        [sessionId]: 'file:src/MentalHealthTrendController.java',
+      },
+    }))
+
+    const view = await renderPanel(sessionId)
+    await waitFor(() => {
+      expect(view.getByTestId('workspace-code').getAttribute('data-highlight-engine')).toBe('shiki')
+    })
+    const tokens = Array.from(view.getByTestId('workspace-code').querySelectorAll<HTMLElement>('[data-workspace-token]'))
+    const tokenColor = (text: string) => tokens.find((token) => token.textContent === text)?.style.color
+
+    expect(tokenColor('package')).toBe('var(--color-code-keyword)')
+    expect(tokenColor('MentalHealthTrendController')).toBe('var(--color-code-type)')
+    expect(tokenColor('countVisibleOrganizations')).toBe('var(--color-code-function)')
+  })
+
   it('can expand long diff previews beyond the default rendered line cap', async () => {
     const longDiff = Array.from({ length: 2300 }, (_, index) => `+line ${index + 1}`).join('\n')
 
diff --git a/desktop/src/components/workspace/WorkspacePanel.tsx b/desktop/src/components/workspace/WorkspacePanel.tsx
index 2f46919e..d514fee8 100644
--- a/desktop/src/components/workspace/WorkspacePanel.tsx
+++ b/desktop/src/components/workspace/WorkspacePanel.tsx
@@ -1,11 +1,13 @@
-import { useCallback, useEffect, useMemo, useRef, useState, type MouseEvent } from 'react'
+import { useCallback, useEffect, useMemo, useRef, useState, type CSSProperties, type KeyboardEvent as ReactKeyboardEvent, type MouseEvent, type RefObject } from 'react'
 import { CircleAlert, Code2, File as FileIcon, FileText, FolderOpen, Image as ImageIcon, MessageCircle, PanelRightClose, PanelRightOpen, RefreshCw, Search, Settings2, X, type LucideIcon } from 'lucide-react'
 import { Highlight } from 'prism-react-renderer'
-import type {
-  WorkspaceChangedFile,
-  WorkspaceFileStatus,
-  WorkspaceTreeEntry,
-  WorkspaceTreeResult,
+import {
+  sessionsApi,
+  type WorkspaceSearchResult,
+  type WorkspaceChangedFile,
+  type WorkspaceFileStatus,
+  type WorkspaceTreeEntry,
+  type WorkspaceTreeResult,
 } from '../../api/sessions'
 import { useTranslation } from '../../i18n'
 import { useShallow } from 'zustand/react/shallow'
@@ -31,6 +33,7 @@ import {
 } from './WorkspaceCodeSurface'
 import { WorkspaceFileOpenWith } from './WorkspaceFileOpenWith'
 import { getFileIdentity, getWorkspaceStatusLabel, type WorkspaceFileIdentity } from './fileIdentity'
+import type { WorkspaceDiffHighlightToken } from './workspaceDiffHighlighter'
 
 type WorkspacePanelProps = {
   sessionId: string
@@ -118,6 +121,7 @@ const EMPTY_EXPANDED_PATHS: string[] = []
 const SELECTION_MENU_OFFSET = 10
 const SELECTION_MENU_WIDTH = 158
 const SELECTION_MENU_HEIGHT = 44
+const WORKSPACE_SEARCH_DEBOUNCE_MS = 250
 const FILE_BADGE_META: Record<string, { label: string; className: string }> = {
   ts: { label: 'TS', className: 'bg-[var(--color-secondary)]/14 text-[var(--color-secondary)]' },
   tsx: { label: 'TSX', className: 'bg-[var(--color-secondary)]/14 text-[var(--color-secondary)]' },
@@ -378,11 +382,13 @@ function PanelMessage({
   message,
   tone = 'muted',
   compact = false,
+  announce = true,
 }: {
   icon: string
   message: string
   tone?: 'muted' | 'error'
   compact?: boolean
+  announce?: boolean
 }) {
   const toneClass =
     tone === 'error'
@@ -392,7 +398,7 @@ function PanelMessage({
   return (
     <div
       className={`flex items-center gap-2 px-4 ${compact ? 'py-2 text-[11px]' : 'py-8 text-xs'} ${toneClass}`}
-      role={tone === 'error' ? 'alert' : 'status'}
+      role={announce ? tone === 'error' ? 'alert' : 'status' : undefined}
     >
       <span className={`material-symbols-outlined shrink-0 text-[16px] ${icon === 'progress_activity' ? 'animate-spin' : ''}`}>
         {icon}
@@ -427,35 +433,62 @@ function WorkspaceFilterInput({
   value,
   onChange,
   summary,
+  mode,
+  loading = false,
+  inputRef,
+  onFocusFirstResult,
 }: {
   value: string
   onChange: (value: string) => void
   summary?: string
+  mode: 'changed' | 'all'
+  loading?: boolean
+  inputRef: RefObject<HTMLInputElement>
+  onFocusFirstResult?: () => void
 }) {
   const t = useTranslation()
+  const placeholder = mode === 'all'
+    ? t('workspace.searchAllPlaceholder')
+    : t('workspace.filterChangedPlaceholder')
 
   return (
     <div className="shrink-0 border-b border-[var(--color-text-primary)]/10 px-3 pb-2.5 pt-2.5">
-      <label className="flex h-9 items-center gap-2 rounded-[7px] bg-[var(--color-surface-container-low)] px-2.5 text-[var(--color-text-tertiary)] shadow-[inset_0_0_0_1px_color-mix(in_srgb,var(--color-text-primary)_8%,transparent)] transition-[background-color,box-shadow] duration-200 ease-out focus-within:bg-[var(--color-surface)] focus-within:shadow-[inset_0_0_0_1px_var(--color-info),0_0_0_3px_color-mix(in_srgb,var(--color-info)_12%,transparent)]">
+      <div className="flex h-9 items-center gap-2 rounded-[7px] bg-[var(--color-surface-container-low)] px-2.5 text-[var(--color-text-tertiary)] shadow-[inset_0_0_0_1px_color-mix(in_srgb,var(--color-text-primary)_8%,transparent)] transition-[background-color,box-shadow] duration-200 ease-out focus-within:bg-[var(--color-surface)] focus-within:shadow-[inset_0_0_0_1px_var(--color-info),0_0_0_3px_color-mix(in_srgb,var(--color-info)_12%,transparent)]">
         <Search size={15} strokeWidth={1.9} aria-hidden="true" className="shrink-0" />
         <input
+          ref={inputRef}
           value={value}
           onChange={(event) => onChange(event.target.value)}
-          aria-label={t('workspace.filterPlaceholder')}
-          placeholder={t('workspace.filterPlaceholder')}
+          onKeyDown={(event) => {
+            if (event.key === 'Escape' && value) {
+              event.preventDefault()
+              onChange('')
+            } else if (event.key === 'ArrowDown' && onFocusFirstResult) {
+              event.preventDefault()
+              onFocusFirstResult()
+            }
+          }}
+          aria-label={placeholder}
+          placeholder={placeholder}
           className="min-w-0 flex-1 bg-transparent text-[13px] text-[var(--color-text-primary)] outline-none placeholder:text-[var(--color-text-tertiary)]"
         />
+        {loading && (
+          <RefreshCw size={13} aria-hidden="true" className="shrink-0 animate-spin" />
+        )}
         {value.length > 0 && (
           <button
             type="button"
             aria-label={t('workspace.clearFilter')}
-            onClick={() => onChange('')}
-            className="inline-flex h-5 w-5 shrink-0 items-center justify-center rounded-[5px] text-[var(--color-text-tertiary)] transition-colors hover:bg-[var(--color-surface-hover)] hover:text-[var(--color-text-primary)]"
+            onClick={() => {
+              onChange('')
+              inputRef.current?.focus()
+            }}
+            className="inline-flex h-7 w-7 shrink-0 items-center justify-center rounded-[6px] text-[var(--color-text-tertiary)] transition-colors hover:bg-[var(--color-surface-hover)] hover:text-[var(--color-text-primary)]"
           >
             <X size={13} strokeWidth={2} aria-hidden="true" />
           </button>
         )}
-      </label>
+      </div>
       {summary && (
         <div
           role="status"
@@ -482,6 +515,15 @@ function FileStatusBadge({ status }: { status: WorkspaceFileStatus }) {
   )
 }
 
+function workspaceCodeTokenStyle(token: WorkspaceDiffHighlightToken): CSSProperties {
+  const fontStyle = token.fontStyle ?? 0
+  return {
+    color: token.color,
+    fontStyle: fontStyle & 1 ? 'italic' : undefined,
+    fontWeight: fontStyle & 2 ? 700 : undefined,
+  }
+}
+
 function CodeSurface({
   value,
   language,
@@ -500,6 +542,7 @@ function CodeSurface({
   const [commentDraft, setCommentDraft] = useState('')
   const [showAllLines, setShowAllLines] = useState(false)
   const [selectionMenu, setSelectionMenu] = useState<FloatingSelectionMenuState | null>(null)
+  const [shikiTokensByLine, setShikiTokensByLine] = useState<WorkspaceDiffHighlightToken[][] | null>(null)
   const lines = value.split('\n')
   const visibleLines = showAllLines ? lines : lines.slice(0, WORKSPACE_PREVIEW_LINE_LIMIT)
   const activeQuote = commentLine ? visibleLines[commentLine - 1] ?? '' : ''
@@ -513,6 +556,27 @@ function CodeSurface({
     setSelectionMenu(null)
   }, [language, value])
 
+  useEffect(() => {
+    if (usePlainLargePreview) {
+      setShikiTokensByLine(null)
+      return
+    }
+
+    let cancelled = false
+    setShikiTokensByLine(null)
+    void import('./workspaceDiffHighlighter')
+      .then(({ highlightWorkspaceCode }) => highlightWorkspaceCode({ value: visibleCode, language }))
+      .then((result) => {
+        if (!cancelled && result.engine === 'shiki') setShikiTokensByLine(result.tokensByLine)
+      })
+      .catch(() => {
+        if (!cancelled) setShikiTokensByLine(null)
+      })
+    return () => {
+      cancelled = true
+    }
+  }, [language, usePlainLargePreview, visibleCode])
+
   const dismissSelectionMenu = useCallback(() => {
     setSelectionMenu(null)
   }, [])
@@ -648,6 +712,40 @@ function CodeSurface({
               )
             })}
           </pre>
+        ) : shikiTokensByLine ? (
+          <pre
+            data-workspace-code=""
+            data-testid="workspace-code"
+            data-highlight-engine="shiki"
+            className="m-0 font-[var(--font-mono)] text-[12px] leading-[1.55]"
+            style={{ color: 'var(--color-code-fg)', background: 'transparent' }}
+          >
+            {shikiTokensByLine.map((line, index) => {
+              const lineNumber = index + 1
+              return (
+                <div key={lineNumber}>
+                  <div
+                    data-workspace-line-number={lineNumber}
+                    className="group grid grid-cols-[48px_minmax(0,1fr)] gap-3 px-3 hover:bg-[var(--color-surface-hover)]"
+                  >
+                    {renderLineNumberButton(lineNumber)}
+                    <span className="whitespace-pre pr-6">
+                      {line.length === 0 ? ' ' : line.map((token, tokenIndex) => (
+                        <span
+                          key={`${tokenIndex}:${token.content}`}
+                          data-workspace-token=""
+                          style={workspaceCodeTokenStyle(token)}
+                        >
+                          {token.content}
+                        </span>
+                      ))}
+                    </span>
+                  </div>
+                  {renderLineCommentEditor(lineNumber)}
+                </div>
+              )
+            })}
+          </pre>
         ) : (
           <Highlight
             theme={workspacePrismTheme}
@@ -658,6 +756,7 @@ function CodeSurface({
               <pre
                 data-workspace-code=""
                 data-testid="workspace-code"
+                data-highlight-engine="prism"
                 className="m-0 font-[var(--font-mono)] text-[12px] leading-[1.55]"
                 style={{ color: 'var(--color-code-fg)', background: 'transparent' }}
               >
@@ -860,6 +959,93 @@ function ChangedFileRow({
   )
 }
 
+function moveWorkspaceSearchResultFocus(
+  event: ReactKeyboardEvent<HTMLButtonElement>,
+  direction: 'next' | 'previous' | 'first' | 'last',
+) {
+  const list = event.currentTarget.closest('[data-workspace-search-results]')
+  const results = list
+    ? Array.from(list.querySelectorAll<HTMLButtonElement>('[data-workspace-search-result]'))
+    : []
+  if (results.length === 0) return
+
+  const currentIndex = results.indexOf(event.currentTarget)
+  const targetIndex = direction === 'first'
+    ? 0
+    : direction === 'last'
+      ? results.length - 1
+      : direction === 'next'
+        ? Math.min(currentIndex + 1, results.length - 1)
+        : Math.max(currentIndex - 1, 0)
+  results[targetIndex]?.focus()
+}
+
+function WorkspaceSearchResultRow({
+  entry,
+  active,
+  onOpen,
+  onContextMenu,
+  onClearSearch,
+}: {
+  entry: WorkspaceTreeEntry
+  active: boolean
+  onOpen: () => void
+  onContextMenu: (event: MouseEvent, path: string, isDirectory: boolean) => void
+  onClearSearch: () => void
+}) {
+  const normalizedPath = entry.path.replace(/\\/g, '/')
+  const lastSlash = normalizedPath.lastIndexOf('/')
+  const parentPath = lastSlash >= 0 ? normalizedPath.slice(0, lastSlash) : '.'
+
+  return (
+    <div role="listitem">
+      <button
+        type="button"
+        data-workspace-search-result=""
+        data-workspace-file-path={entry.path}
+        aria-current={active ? 'true' : undefined}
+        aria-label={`${entry.name}, ${parentPath}`}
+        title={normalizedPath}
+        onClick={onOpen}
+        onContextMenu={(event) => onContextMenu(event, entry.path, false)}
+        onKeyDown={(event) => {
+          if (event.key === 'ArrowDown') {
+            event.preventDefault()
+            moveWorkspaceSearchResultFocus(event, 'next')
+          } else if (event.key === 'ArrowUp') {
+            event.preventDefault()
+            moveWorkspaceSearchResultFocus(event, 'previous')
+          } else if (event.key === 'Home') {
+            event.preventDefault()
+            moveWorkspaceSearchResultFocus(event, 'first')
+          } else if (event.key === 'End') {
+            event.preventDefault()
+            moveWorkspaceSearchResultFocus(event, 'last')
+          } else if (event.key === 'Escape') {
+            event.preventDefault()
+            onClearSearch()
+          }
+        }}
+        className={`group mx-2 flex min-h-12 w-[calc(100%-16px)] items-start gap-2 rounded-[7px] px-2.5 py-2 text-left transition-[background-color,transform] duration-150 ease-out active:scale-[0.99] ${
+          active
+            ? 'bg-[var(--color-info-container)] shadow-[inset_3px_0_0_var(--color-info)]'
+            : 'hover:bg-[var(--color-surface-hover)]'
+        }`}
+      >
+        <FileTypeBadge name={entry.name} subtle={!active} />
+        <span className="min-w-0 flex-1">
+          <span className="block truncate text-[13px] font-medium text-[var(--color-text-primary)]">
+            {entry.name}
+          </span>
+          <span className="mt-0.5 block truncate font-[var(--font-mono)] text-[10px] text-[var(--color-text-tertiary)]">
+            {parentPath}
+          </span>
+        </span>
+      </button>
+    </div>
+  )
+}
+
 function TreeNode({
   sessionId,
   entry,
@@ -889,6 +1075,7 @@ function TreeNode({
         type="button"
         onClick={() => onOpenFile(entry.path)}
         onContextMenu={(event) => onFileContextMenu(event, entry.path, false)}
+        aria-current={isActive ? 'true' : undefined}
         className={`group mx-2 flex h-8 w-[calc(100%-16px)] items-center gap-2 rounded-[7px] pr-2 text-left transition-colors ${
           isActive
             ? 'bg-[var(--color-surface-selected)] shadow-[inset_0_0_0_1.5px_var(--color-border-focus)]'
@@ -912,7 +1099,7 @@ function TreeNode({
         className="group mx-2 flex h-8 w-[calc(100%-16px)] items-center gap-2 rounded-[7px] pr-2 text-left transition-colors hover:bg-[var(--color-surface-hover)]"
         style={{ paddingLeft: indent }}
       >
-        <span className="material-symbols-outlined shrink-0 text-[18px] text-[var(--color-text-tertiary)] transition-colors group-hover:text-[var(--color-text-primary)]">
+        <span aria-hidden="true" className="material-symbols-outlined shrink-0 text-[18px] text-[var(--color-text-tertiary)] transition-colors group-hover:text-[var(--color-text-primary)]">
           {isVisuallyExpanded ? 'expand_more' : 'chevron_right'}
         </span>
         <span className="min-w-0 truncate text-[15px] font-medium text-[var(--color-text-primary)]">{entry.name}</span>
@@ -985,6 +1172,10 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
   const t = useTranslation()
   const addToast = useUIStore((state) => state.addToast)
   const [filterQuery, setFilterQuery] = useState('')
+  const [workspaceSearch, setWorkspaceSearch] = useState<WorkspaceSearchResult | null>(null)
+  const [workspaceSearchLoading, setWorkspaceSearchLoading] = useState(false)
+  const [workspaceSearchError, setWorkspaceSearchError] = useState<string | null>(null)
+  const [workspaceSearchRevision, setWorkspaceSearchRevision] = useState(0)
   const [isViewMenuOpen, setIsViewMenuOpen] = useState(false)
   const [isNavigatorOpen, setIsNavigatorOpen] = useState(forceVisible)
   const [previewTabContextMenu, setPreviewTabContextMenu] = useState<{ tabId: string; x: number; y: number } | null>(null)
@@ -1021,18 +1212,27 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
     isOpen: false,
     chatState: 'idle',
   })
+  const workspaceSearchRequestIdRef = useRef(0)
+  const filterInputRef = useRef<HTMLInputElement>(null)
+  const previewHeaderRef = useRef<HTMLDivElement>(null)
 
   const rootTree = treeByPath['']
   const rootTreeKey = makeTreeStateKey(sessionId, '')
   const rootTreeLoading = treeLoadingByPath[rootTreeKey] ?? false
   const rootTreeError = treeErrorsByPath[rootTreeKey] ?? null
   const normalizedFilterQuery = normalizeFilterQuery(filterQuery)
-  const expandedPathSet = new Set(expandedPaths)
   const activePreviewTab =
     previewTabs.find((tab) => tab.id === activePreviewTabId) ?? previewTabs[previewTabs.length - 1] ?? null
   const hasPreviewTabs = previewTabs.length > 0
   const isNavigatorVisible = !hasPreviewTabs || isNavigatorOpen
-  const navigatorView = hasPreviewTabs ? 'changed' : activeView
+  const navigatorView = activeView
+  const hasWorkspaceSearch = navigatorView === 'all' && normalizedFilterQuery.length > 0
+  const activeWorkspaceSearch = workspaceSearch
+    && normalizeFilterQuery(workspaceSearch.query) === normalizedFilterQuery
+    ? workspaceSearch
+    : null
+  const displayedWorkspaceSearch = activeWorkspaceSearch ?? workspaceSearch
+  const expandedPathSet = new Set(expandedPaths)
   const activeTreePath = activePreviewTab?.kind === 'file' ? activePreviewTab.path : null
   const activeChangedFile = activePreviewTab
     ? status?.changedFiles.find((file) => file.path === activePreviewTab.path) ?? null
@@ -1051,17 +1251,19 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
       : [],
     [normalizedFilterQuery, rootTree, treeByPath],
   )
-  const visibleEntryCount = navigatorView === 'changed' ? filteredChangedFiles.length : filteredRootEntries.length
-  const totalEntryCount = navigatorView === 'changed'
-    ? status?.changedFiles.length ?? 0
-    : rootTree?.state === 'ok' ? rootTree.entries.length : 0
+  const visibleEntryCount = filteredChangedFiles.length
+  const totalEntryCount = status?.changedFiles.length ?? 0
   const filterSummary = navigatorView === 'changed'
     ? normalizedFilterQuery
       ? t('workspace.filteredFilesCount', { visible: visibleEntryCount, total: totalEntryCount })
       : t('workspace.filesCount', { count: totalEntryCount })
-    : normalizedFilterQuery
-      ? t('workspace.filteredItemsCount', { visible: visibleEntryCount, total: totalEntryCount })
-      : t('workspace.itemsCount', { count: totalEntryCount })
+    : !normalizedFilterQuery || workspaceSearchError
+      ? undefined
+      : workspaceSearchLoading || !activeWorkspaceSearch
+        ? t('workspace.searching')
+        : activeWorkspaceSearch.truncated
+          ? t('workspace.searchResultsTruncated', { count: activeWorkspaceSearch.entries.length })
+          : t('workspace.searchResultsCount', { count: activeWorkspaceSearch.entries.length })
   const activePreviewRequestKey = activePreviewTab
     ? makePreviewStateKey(sessionId, activePreviewTab.id)
     : null
@@ -1098,6 +1300,38 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
     void loadTree(sessionId, '')
   }, [isNavigatorVisible, loadTree, navigatorView, rootTree, rootTreeError, rootTreeLoading, sessionId, shouldRender])
 
+  useEffect(() => {
+    const requestId = workspaceSearchRequestIdRef.current + 1
+    workspaceSearchRequestIdRef.current = requestId
+
+    if (!shouldRender || navigatorView !== 'all' || !normalizedFilterQuery) {
+      if (!normalizedFilterQuery) setWorkspaceSearch(null)
+      setWorkspaceSearchLoading(false)
+      setWorkspaceSearchError(null)
+      return
+    }
+
+    setWorkspaceSearchLoading(true)
+    setWorkspaceSearchError(null)
+    let cancelled = false
+    const timer = window.setTimeout(() => {
+      void sessionsApi.searchWorkspace(sessionId, filterQuery.trim()).then((result) => {
+        if (cancelled || workspaceSearchRequestIdRef.current !== requestId) return
+        setWorkspaceSearch(result)
+        setWorkspaceSearchLoading(false)
+      }).catch((error) => {
+        if (cancelled || workspaceSearchRequestIdRef.current !== requestId) return
+        setWorkspaceSearchLoading(false)
+        setWorkspaceSearchError(error instanceof Error ? error.message : t('workspace.loadError'))
+      })
+    }, WORKSPACE_SEARCH_DEBOUNCE_MS)
+
+    return () => {
+      cancelled = true
+      window.clearTimeout(timer)
+    }
+  }, [filterQuery, navigatorView, normalizedFilterQuery, sessionId, shouldRender, t, workspaceSearchRevision])
+
   useEffect(() => {
     if (!previewTabContextMenu && !fileContextMenu) return
     const close = () => {
@@ -1131,19 +1365,38 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
     if (activePreviewTab) {
       void openPreview(sessionId, activePreviewTab.path, activePreviewTab.kind)
     }
-    if (navigatorView === 'all') {
+    if (hasWorkspaceSearch) {
+      setWorkspaceSearchRevision((revision) => revision + 1)
+    } else if (navigatorView === 'all') {
       void loadTree(sessionId, '')
     }
   }
 
+  const focusPreviewAfterOpen = () => {
+    window.setTimeout(() => previewHeaderRef.current?.focus(), 0)
+  }
+
   const handleOpenDiff = (path: string) => {
     setIsNavigatorOpen(forceVisible)
     void openPreview(sessionId, path, 'diff')
+    focusPreviewAfterOpen()
   }
 
   const handleOpenFile = (path: string) => {
     setIsNavigatorOpen(forceVisible)
     void openPreview(sessionId, path, 'file')
+    focusPreviewAfterOpen()
+  }
+
+  const clearWorkspaceSearch = () => {
+    setFilterQuery('')
+    window.requestAnimationFrame(() => filterInputRef.current?.focus())
+  }
+
+  const focusFirstSearchResult = () => {
+    document.querySelector<HTMLButtonElement>(
+      `[data-testid="workspace-panel"] [data-workspace-search-result]`,
+    )?.focus()
   }
 
   const addWorkspacePathToChat = (path: string, isDirectory = false) => {
@@ -1302,6 +1555,69 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
   }
 
   const renderAllFilesView = () => {
+    if (hasWorkspaceSearch) {
+      if (workspaceSearchLoading && !displayedWorkspaceSearch) {
+        return <PanelMessage announce={false} icon="progress_activity" message={t('workspace.searching')} />
+      }
+      if (workspaceSearchError && !displayedWorkspaceSearch) {
+        return (
+          <div role="alert" className="mx-3 my-3 rounded-[8px] border border-[var(--color-error)]/20 bg-[var(--color-error)]/6 p-3 text-[12px] text-[var(--color-error)]">
+            <div className="flex items-start gap-2">
+              <CircleAlert size={15} aria-hidden="true" className="mt-0.5 shrink-0" />
+              <span className="min-w-0 flex-1 leading-5">{workspaceSearchError}</span>
+            </div>
+            <button
+              type="button"
+              onClick={() => setWorkspaceSearchRevision((revision) => revision + 1)}
+              className="mt-2 rounded-[6px] border border-[var(--color-error)]/30 px-2 py-1 font-medium hover:bg-[var(--color-error)]/10 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[var(--color-error)]/25"
+            >
+              {t('common.retry')}
+            </button>
+          </div>
+        )
+      }
+      if (!displayedWorkspaceSearch) {
+        return <PanelMessage announce={false} icon="progress_activity" message={t('workspace.searching')} />
+      }
+      if (!workspaceSearchLoading && activeWorkspaceSearch?.entries.length === 0) {
+        return <PanelMessage announce={false} icon="search_off" message={t('workspace.noMatchingFiles')} />
+      }
+
+      return (
+        <div
+          role="list"
+          aria-label={t('workspace.searchResults')}
+          aria-busy={workspaceSearchLoading}
+          data-workspace-search-results=""
+          className="space-y-0.5 py-1"
+        >
+          {workspaceSearchError && (
+            <div role="alert" className="mx-3 mb-2 flex items-center gap-2 rounded-[7px] bg-[var(--color-error)]/6 px-2.5 py-2 text-[11px] text-[var(--color-error)]">
+              <CircleAlert size={14} aria-hidden="true" className="shrink-0" />
+              <span className="min-w-0 flex-1 truncate">{workspaceSearchError}</span>
+              <button
+                type="button"
+                onClick={() => setWorkspaceSearchRevision((revision) => revision + 1)}
+                className="shrink-0 rounded-[5px] px-1.5 py-1 font-medium hover:bg-[var(--color-error)]/10"
+              >
+                {t('common.retry')}
+              </button>
+            </div>
+          )}
+          {displayedWorkspaceSearch.entries.map((entry) => (
+            <WorkspaceSearchResultRow
+              key={entry.path}
+              entry={entry}
+              active={activeTreePath === entry.path}
+              onOpen={() => handleOpenFile(entry.path)}
+              onContextMenu={handleFileContextMenu}
+              onClearSearch={clearWorkspaceSearch}
+            />
+          ))}
+        </div>
+      )
+    }
+
     if (rootTreeLoading && !rootTree) {
       return <PanelMessage icon="progress_activity" message={t('common.loading')} />
     }
@@ -1375,8 +1691,10 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
         className="flex min-h-0 flex-1 flex-col"
       >
         <div
+          ref={previewHeaderRef}
+          tabIndex={-1}
           data-testid="workspace-preview-header"
-          className="flex h-10 shrink-0 items-center gap-2 border-b border-[var(--color-text-primary)]/10 bg-[var(--color-surface)] px-3 text-[12px]"
+          className="flex h-10 shrink-0 items-center gap-2 border-b border-[var(--color-text-primary)]/10 bg-[var(--color-surface)] px-3 text-[12px] focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-[var(--color-info)]/35"
         >
           <FileText size={15} strokeWidth={1.8} aria-hidden="true" className="shrink-0 text-[var(--color-text-tertiary)]" />
           <span className="min-w-0 truncate font-medium text-[var(--color-text-primary)]">{activePreviewTab.path}</span>
@@ -1400,7 +1718,11 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
             <ToolbarIconButton
               Icon={isNavigatorVisible ? PanelRightClose : PanelRightOpen}
               label={isNavigatorVisible ? t('workspace.hideNavigator') : t('workspace.showNavigator')}
-              onClick={() => setIsNavigatorOpen((open) => !open)}
+              onClick={() => setIsNavigatorOpen((open) => {
+                const nextOpen = !open
+                if (nextOpen) window.requestAnimationFrame(() => filterInputRef.current?.focus())
+                return nextOpen
+              })}
             />
             {!embedded && (
               <ToolbarIconButton Icon={X} label={t('workspace.closePanel')} onClick={() => closePanel(sessionId)} />
@@ -1608,11 +1930,10 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
             data-testid="workspace-file-navigator"
             className={`${hasPreviewTabs ? 'border-l border-[var(--color-text-primary)]/10' : ''} ${hasPreviewTabs && !forceVisible ? 'absolute inset-y-0 right-0 z-20 w-[min(280px,100%)] shadow-[-12px_0_28px_rgba(15,23,42,0.08)]' : ''} flex min-h-0 flex-col bg-[var(--color-surface)]`}
           >
-            {!hasPreviewTabs && (
-              <header
-                data-testid="workspace-file-navigator-header"
-                className="flex h-10 shrink-0 items-center gap-1.5 border-b border-[var(--color-text-primary)]/10 px-3"
-              >
+            <header
+              data-testid="workspace-file-navigator-header"
+              className="flex h-10 shrink-0 items-center gap-1.5 border-b border-[var(--color-text-primary)]/10 px-3"
+            >
               <div className="relative min-w-0">
               <button
                 type="button"
@@ -1625,7 +1946,7 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
                 <span className="truncate">
                   {activeView === 'changed' ? t('workspace.changedFiles') : t('workspace.allFiles')}
                 </span>
-                <span className="material-symbols-outlined shrink-0 text-[15px] font-normal text-[var(--color-text-tertiary)]">expand_more</span>
+                <span aria-hidden="true" className="material-symbols-outlined shrink-0 text-[15px] font-normal text-[var(--color-text-tertiary)]">expand_more</span>
               </button>
               {isViewMenuOpen && (
                 <div
@@ -1648,7 +1969,7 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
                           {view === 'changed' ? t('workspace.changedFiles') : t('workspace.allFiles')}
                         </span>
                         {selected && (
-                          <span className="material-symbols-outlined text-[14px] text-[var(--color-brand)]">check</span>
+                          <span aria-hidden="true" className="material-symbols-outlined text-[14px] text-[var(--color-brand)]">check</span>
                         )}
                       </button>
                     )
@@ -1664,13 +1985,16 @@ export function WorkspacePanel({ sessionId, embedded = false, forceVisible = fal
                   )}
                 </div>
               )}
-              </header>
-            )}
+            </header>
 
             <WorkspaceFilterInput
               value={filterQuery}
               onChange={setFilterQuery}
               summary={normalizedFilterQuery ? filterSummary : undefined}
+              mode={navigatorView}
+              loading={hasWorkspaceSearch && workspaceSearchLoading}
+              inputRef={filterInputRef}
+              onFocusFirstResult={hasWorkspaceSearch ? focusFirstSearchResult : undefined}
             />
 
             <div className="min-h-0 flex-1 overflow-auto py-1.5">
diff --git a/desktop/src/components/workspace/workspaceDiffHighlighter.test.ts b/desktop/src/components/workspace/workspaceDiffHighlighter.test.ts
index 340106c9..c65a22e2 100644
--- a/desktop/src/components/workspace/workspaceDiffHighlighter.test.ts
+++ b/desktop/src/components/workspace/workspaceDiffHighlighter.test.ts
@@ -2,6 +2,7 @@ import { describe, expect, it } from 'vitest'
 import { parseWorkspaceDiff } from './workspaceDiffModel'
 import {
   buildWorkspaceDiffWordRanges,
+  highlightWorkspaceCode,
   highlightWorkspaceDiff,
 } from './workspaceDiffHighlighter'
 
@@ -13,6 +14,25 @@ function findRowId(diff: string, text: string) {
 }
 
 describe('workspaceDiffHighlighter', () => {
+  it('loads the Java grammar for regular workspace file previews', async () => {
+    const result = await highlightWorkspaceCode({
+      language: 'java',
+      value: [
+        'package com.example.campus;',
+        'public final class MentalHealthTrendController {',
+        '  private String campusId;',
+        '  public int countVisibleOrganizations() { return 1; }',
+        '}',
+      ].join('\n'),
+    })
+    const tokens = result.tokensByLine.flat()
+
+    expect(result.engine).toBe('shiki')
+    expect(tokens.some((token) => token.content === 'package' && token.color === 'var(--color-code-keyword)')).toBe(true)
+    expect(tokens.some((token) => token.content === 'MentalHealthTrendController' && token.color === 'var(--color-code-type)')).toBe(true)
+    expect(tokens.some((token) => token.content === 'countVisibleOrganizations' && token.color === 'var(--color-code-function)')).toBe(true)
+  })
+
   it('keeps TextMate grammar state across the rows in one diff hunk', async () => {
     const diff = [
       'diff --git a/src/a.ts b/src/a.ts',
diff --git a/desktop/src/components/workspace/workspaceDiffHighlighter.ts b/desktop/src/components/workspace/workspaceDiffHighlighter.ts
index ac685630..e6eaed31 100644
--- a/desktop/src/components/workspace/workspaceDiffHighlighter.ts
+++ b/desktop/src/components/workspace/workspaceDiffHighlighter.ts
@@ -24,6 +24,11 @@ export interface WorkspaceDiffHighlightResult {
   wordRangesByRowId: Record<string, WorkspaceDiffWordRange[]>
 }
 
+export interface WorkspaceCodeHighlightResult {
+  engine: 'shiki' | 'plain'
+  tokensByLine: WorkspaceDiffHighlightToken[][]
+}
+
 interface WordSegment extends WorkspaceDiffWordRange {
   text: string
 }
@@ -220,6 +225,31 @@ const workspaceDiffShikiTheme: ThemeRegistration = {
   ],
 }
 
+const workspaceCodeShikiTheme: ThemeRegistration = {
+  name: 'codex-workspace-code',
+  type: 'dark',
+  fg: 'var(--color-code-fg)',
+  bg: 'transparent',
+  settings: [
+    { settings: { foreground: 'var(--color-code-fg)', background: 'transparent' } },
+    { scope: ['comment', 'punctuation.definition.comment'], settings: { foreground: 'var(--color-code-comment)', fontStyle: 'italic' } },
+    { scope: ['string', 'string.quoted', 'string.template', 'string.other.link'], settings: { foreground: 'var(--color-code-string)' } },
+    { scope: ['string.regexp'], settings: { foreground: 'var(--color-primary-container)' } },
+    { scope: ['keyword', 'keyword.control', 'storage', 'storage.type', 'storage.modifier'], settings: { foreground: 'var(--color-code-keyword)' } },
+    { scope: ['keyword.operator'], settings: { foreground: 'var(--color-code-keyword)' } },
+    { scope: ['entity.name.function', 'support.function', 'meta.function-call'], settings: { foreground: 'var(--color-code-function)' } },
+    { scope: ['entity.name.type', 'support.type', 'support.class', 'entity.name.class', 'entity.other.inherited-class'], settings: { foreground: 'var(--color-code-type)' } },
+    { scope: ['variable.parameter'], settings: { foreground: 'var(--color-code-parameter)' } },
+    { scope: ['variable.other.property', 'support.type.property-name', 'meta.object-literal.key'], settings: { foreground: 'var(--color-code-property)' } },
+    { scope: ['variable.other.constant', 'variable.other.enummember'], settings: { foreground: 'var(--color-code-type)' } },
+    { scope: ['constant.numeric', 'constant.language'], settings: { foreground: 'var(--color-code-number)' } },
+    { scope: ['punctuation', 'meta.brace', 'meta.bracket'], settings: { foreground: 'var(--color-code-punctuation)' } },
+    { scope: ['entity.name.tag', 'punctuation.definition.tag'], settings: { foreground: 'var(--color-code-keyword)' } },
+    { scope: ['entity.other.attribute-name'], settings: { foreground: 'var(--color-code-property)' } },
+    { scope: ['meta.decorator', 'punctuation.decorator'], settings: { foreground: 'var(--color-code-type)' } },
+  ],
+}
+
 const workspaceDiffLanguageLoaders: Record<string, () => Promise<LanguageRegistration[]>> = {
   bash: () => import('@shikijs/langs/bash').then((module) => module.default),
   c: () => import('@shikijs/langs/c').then((module) => module.default),
@@ -313,7 +343,7 @@ const workspaceDiffLanguagePromises = new Map<string, Promise<void>>()
 
 function getWorkspaceDiffHighlighter() {
   workspaceDiffHighlighterPromise ??= createHighlighterCore({
-    themes: [workspaceDiffShikiTheme],
+    themes: [workspaceDiffShikiTheme, workspaceCodeShikiTheme],
     langs: [],
     engine: createOnigurumaEngine(import('shiki/wasm')),
   })
@@ -348,6 +378,12 @@ export function getWorkspaceDiffShikiLanguage(path: string) {
   return shikiLanguageAliases[extension] ?? 'text'
 }
 
+export function getWorkspaceCodeShikiLanguage(language: string) {
+  const normalized = language.trim().toLowerCase()
+  if (workspaceDiffLanguageLoaders[normalized]) return normalized
+  return shikiLanguageAliases[normalized] ?? 'text'
+}
+
 function tokenizeWords(value: string): WordSegment[] {
   const segments: WordSegment[] = []
   const pattern = /\s+|[\p{L}\p{N}_$]+|[^\s\p{L}\p{N}_$]+/gu
@@ -536,3 +572,32 @@ export async function highlightWorkspaceDiff({
     return { engine: 'plain', tokensByRowId: {}, wordRangesByRowId }
   }
 }
+
+export async function highlightWorkspaceCode({
+  value,
+  language,
+}: {
+  value: string
+  language: string
+}): Promise<WorkspaceCodeHighlightResult> {
+  try {
+    const highlighter = await getWorkspaceDiffHighlighter()
+    const normalizedLanguage = getWorkspaceCodeShikiLanguage(language)
+    await ensureWorkspaceDiffLanguage(highlighter, normalizedLanguage)
+    const result = highlighter.codeToTokens(value, {
+      lang: workspaceDiffLanguageLoaders[normalizedLanguage] ? normalizedLanguage : 'text',
+      theme: workspaceCodeShikiTheme,
+      tokenizeMaxLineLength: WORKSPACE_DIFF_TOKENIZE_MAX_LINE_LENGTH,
+    })
+    return {
+      engine: 'shiki',
+      tokensByLine: result.tokens.map((line) => line.map((token) => ({
+        content: token.content,
+        color: token.color,
+        fontStyle: token.fontStyle,
+      }))),
+    }
+  } catch {
+    return { engine: 'plain', tokensByLine: [] }
+  }
+}
diff --git a/desktop/src/i18n/locales/en.ts b/desktop/src/i18n/locales/en.ts
index fcb1cf18..917b7429 100644
--- a/desktop/src/i18n/locales/en.ts
+++ b/desktop/src/i18n/locales/en.ts
@@ -134,7 +134,13 @@ export const en = {
   'workspace.viewTabs': 'Workspace views',
   'workspace.previewTabs': 'Preview tabs',
   'workspace.filterPlaceholder': 'Filter files...',
+  'workspace.filterChangedPlaceholder': 'Filter changed files...',
+  'workspace.searchAllPlaceholder': 'Search all files...',
   'workspace.clearFilter': 'Clear file filter',
+  'workspace.searching': 'Searching workspace...',
+  'workspace.searchResults': 'File search results',
+  'workspace.searchResultsCount': '{count} search results',
+  'workspace.searchResultsTruncated': 'Showing the first {count} results. Refine your search.',
   'workspace.reviewWorkspace': 'Review workspace',
   'workspace.filesCount': '{count} files',
   'workspace.filteredFilesCount': '{visible} of {total} files',
diff --git a/desktop/src/i18n/locales/jp.ts b/desktop/src/i18n/locales/jp.ts
index 84b1cb47..7c466628 100644
--- a/desktop/src/i18n/locales/jp.ts
+++ b/desktop/src/i18n/locales/jp.ts
@@ -136,7 +136,13 @@ export const jp: Record<TranslationKey, string> = {
   'workspace.viewTabs': 'ワークスペースビュー',
   'workspace.previewTabs': 'プレビュータブ',
   'workspace.filterPlaceholder': 'ファイルを絞り込み...',
+  'workspace.filterChangedPlaceholder': '変更されたファイルを絞り込み...',
+  'workspace.searchAllPlaceholder': 'すべてのファイルを検索...',
   'workspace.clearFilter': 'ファイルフィルターをクリア',
+  'workspace.searching': 'ワークスペースを検索中...',
+  'workspace.searchResults': 'ファイル検索結果',
+  'workspace.searchResultsCount': '{count} 件の検索結果',
+  'workspace.searchResultsTruncated': '最初の {count} 件を表示しています。検索を絞り込んでください。',
   'workspace.reviewWorkspace': 'ワークスペースをレビュー',
   'workspace.filesCount': '{count} ファイル',
   'workspace.filteredFilesCount': '{total} 件中 {visible} ファイル',
diff --git a/desktop/src/i18n/locales/kr.ts b/desktop/src/i18n/locales/kr.ts
index 6d4770df..25836abd 100644
--- a/desktop/src/i18n/locales/kr.ts
+++ b/desktop/src/i18n/locales/kr.ts
@@ -136,7 +136,13 @@ export const kr: Record<TranslationKey, string> = {
   'workspace.viewTabs': '작업 공간 보기',
   'workspace.previewTabs': '미리 보기 탭',
   'workspace.filterPlaceholder': '파일 필터링...',
+  'workspace.filterChangedPlaceholder': '변경된 파일 필터링...',
+  'workspace.searchAllPlaceholder': '모든 파일 검색...',
   'workspace.clearFilter': '파일 필터 지우기',
+  'workspace.searching': '작업 공간 검색 중...',
+  'workspace.searchResults': '파일 검색 결과',
+  'workspace.searchResultsCount': '검색 결과 {count}개',
+  'workspace.searchResultsTruncated': '처음 {count}개 결과를 표시합니다. 검색어를 구체화하세요.',
   'workspace.reviewWorkspace': '작업 공간 검토',
   'workspace.filesCount': '파일 {count}개',
   'workspace.filteredFilesCount': '파일 {total}개 중 {visible}개',
diff --git a/desktop/src/i18n/locales/zh-TW.ts b/desktop/src/i18n/locales/zh-TW.ts
index 4ded849e..4c7ca334 100644
--- a/desktop/src/i18n/locales/zh-TW.ts
+++ b/desktop/src/i18n/locales/zh-TW.ts
@@ -136,7 +136,13 @@ export const zh: Record<TranslationKey, string> = {
   'workspace.viewTabs': '工作區檢視',
   'workspace.previewTabs': '預覽標籤',
   'workspace.filterPlaceholder': '篩選檔案...',
+  'workspace.filterChangedPlaceholder': '篩選已更改檔案...',
+  'workspace.searchAllPlaceholder': '搜尋所有檔案...',
   'workspace.clearFilter': '清除檔案篩選',
+  'workspace.searching': '正在搜尋工作區...',
+  'workspace.searchResults': '檔案搜尋結果',
+  'workspace.searchResultsCount': '找到 {count} 個結果',
+  'workspace.searchResultsTruncated': '顯示前 {count} 個結果，請縮小搜尋範圍。',
   'workspace.reviewWorkspace': '審閱工作區',
   'workspace.filesCount': '{count} 個檔案',
   'workspace.filteredFilesCount': '{visible} / {total} 個檔案',
diff --git a/desktop/src/i18n/locales/zh.ts b/desktop/src/i18n/locales/zh.ts
index eb9b01c1..211d8573 100644
--- a/desktop/src/i18n/locales/zh.ts
+++ b/desktop/src/i18n/locales/zh.ts
@@ -136,7 +136,13 @@ export const zh: Record<TranslationKey, string> = {
   'workspace.viewTabs': '工作区视图',
   'workspace.previewTabs': '预览标签',
   'workspace.filterPlaceholder': '筛选文件...',
+  'workspace.filterChangedPlaceholder': '筛选已更改文件...',
+  'workspace.searchAllPlaceholder': '搜索所有文件...',
   'workspace.clearFilter': '清除文件筛选',
+  'workspace.searching': '正在搜索工作区...',
+  'workspace.searchResults': '文件搜索结果',
+  'workspace.searchResultsCount': '找到 {count} 个结果',
+  'workspace.searchResultsTruncated': '显示前 {count} 个结果，请缩小搜索范围。',
   'workspace.reviewWorkspace': '审阅工作区',
   'workspace.filesCount': '{count} 个文件',
   'workspace.filteredFilesCount': '{visible} / {total} 个文件',
diff --git a/desktop/src/pages/TraceSession.test.tsx b/desktop/src/pages/TraceSession.test.tsx
index d711c981..fdc3f711 100644
--- a/desktop/src/pages/TraceSession.test.tsx
+++ b/desktop/src/pages/TraceSession.test.tsx
@@ -421,12 +421,16 @@ describe('TraceSession', () => {
 
   it('refetches messages when only the trace message signature changes', async () => {
     const pendingMessages = baseMessages.filter((message) => message.type !== 'tool_result')
+    let resolveRefreshedMessages!: (value: { messages: MessageEntry[] }) => void
+    const refreshedMessages = new Promise<{ messages: MessageEntry[] }>((resolve) => {
+      resolveRefreshedMessages = resolve
+    })
     vi.mocked(sessionsApi.getTrace)
       .mockResolvedValueOnce({ ...baseTrace, messageSignature: '3:tool-use' })
       .mockResolvedValue({ ...baseTrace, messageSignature: '4:tool-result' })
     vi.mocked(sessionsApi.getMessages)
       .mockResolvedValueOnce({ messages: pendingMessages })
-      .mockResolvedValue({ messages: baseMessages })
+      .mockReturnValue(refreshedMessages)
 
     await renderReady(20)
 
@@ -435,7 +439,8 @@ describe('TraceSession', () => {
     expect(within(screen.getByTestId('trace-detail')).queryByText('file.txt')).not.toBeInTheDocument()
 
     await waitFor(() => expect(sessionsApi.getMessages).toHaveBeenCalledTimes(2))
-    expect(within(screen.getByTestId('trace-detail')).getByText('file.txt')).toBeInTheDocument()
+    resolveRefreshedMessages({ messages: baseMessages })
+    expect(await within(screen.getByTestId('trace-detail')).findByText('file.txt')).toBeInTheDocument()
   })
 
   it('applies poll updates when a call changes without changing row counts', async () => {
diff --git a/src/server/__tests__/sessions.test.ts b/src/server/__tests__/sessions.test.ts
index 93f68dfd..ffe55d59 100644
--- a/src/server/__tests__/sessions.test.ts
+++ b/src/server/__tests__/sessions.test.ts
@@ -143,14 +143,32 @@ async function createWorkspaceApiGitRepo(baseDir: string): Promise<string> {
     `workspace-api-${Date.now()}-${Math.random().toString(36).slice(2)}`,
   )
 
+  const javaControllerDir = path.join(
+    workDir,
+    'services',
+    'mental-health-service',
+    'src',
+    'main',
+    'java',
+    'com',
+    'example',
+    'campus',
+    'mentalhealth',
+    'controller',
+  )
   await fs.mkdir(path.join(workDir, 'src'), { recursive: true })
+  await fs.mkdir(javaControllerDir, { recursive: true })
   git(workDir, 'init')
   git(workDir, 'config', 'user.email', 'sessions-api@example.com')
   git(workDir, 'config', 'user.name', 'Sessions API')
 
   await fs.writeFile(path.join(workDir, 'tracked.txt'), 'before\n')
   await fs.writeFile(path.join(workDir, 'src', 'app.ts'), 'export const answer = 42\n')
-  git(workDir, 'add', 'tracked.txt', 'src/app.ts')
+  await fs.writeFile(
+    path.join(javaControllerDir, 'MentalHealthTrendController.java'),
+    'package com.example.campus.mentalhealth.controller;\n\npublic final class MentalHealthTrendController {}\n',
+  )
+  git(workDir, 'add', 'tracked.txt', 'src/app.ts', 'services')
   git(workDir, 'commit', '-m', 'initial')
 
   await fs.writeFile(path.join(workDir, 'tracked.txt'), 'before\nafter\n')
@@ -3370,7 +3388,7 @@ describe('Sessions API', () => {
     )
   })
 
-  it('GET /api/sessions/:id/workspace/status|tree|file|diff should return workspace data', async () => {
+  it('GET /api/sessions/:id/workspace/status|tree|search|file|diff should return workspace data', async () => {
     const workDir = await createWorkspaceApiGitRepo(tmpDir)
     const { sessionId } = await service.createSession(workDir)
 
@@ -3403,10 +3421,26 @@ describe('Sessions API', () => {
       path: '',
     })
     expect(treeBody.entries).toEqual([
+      { name: 'services', path: 'services', isDirectory: true },
       { name: 'src', path: 'src', isDirectory: true },
       { name: 'tracked.txt', path: 'tracked.txt', isDirectory: false },
     ])
 
+    const searchRes = await fetch(
+      `${baseUrl}/api/sessions/${sessionId}/workspace/search?query=${encodeURIComponent('MentalHealthTrendController')}`,
+    )
+    expect(searchRes.status).toBe(200)
+    expect(await searchRes.json()).toMatchObject({
+      state: 'ok',
+      query: 'MentalHealthTrendController',
+      truncated: false,
+      entries: [{
+        name: 'MentalHealthTrendController.java',
+        path: 'services/mental-health-service/src/main/java/com/example/campus/mentalhealth/controller/MentalHealthTrendController.java',
+        isDirectory: false,
+      }],
+    })
+
     const fileRes = await fetch(
       `${baseUrl}/api/sessions/${sessionId}/workspace/file?path=${encodeURIComponent('src/app.ts')}`,
     )
@@ -3714,6 +3748,17 @@ describe('Sessions API', () => {
     }
   })
 
+  it('GET /api/sessions/:id/workspace/search should require a non-empty query', async () => {
+    const workDir = await createWorkspaceApiGitRepo(tmpDir)
+    const { sessionId } = await service.createSession(workDir)
+
+    for (const suffix of ['', '?query=%20%20']) {
+      const res = await fetch(`${baseUrl}/api/sessions/${sessionId}/workspace/search${suffix}`)
+      expect(res.status).toBe(400)
+      expect(await res.json()).toMatchObject({ error: 'BAD_REQUEST' })
+    }
+  })
+
   it('GET /api/sessions/:id/workspace/file and tree should reject traversal with 403', async () => {
     const workDir = await createWorkspaceApiGitRepo(tmpDir)
     const { sessionId } = await service.createSession(workDir)
diff --git a/src/server/api/filesystem.ts b/src/server/api/filesystem.ts
index 1056374e..edac419e 100644
--- a/src/server/api/filesystem.ts
+++ b/src/server/api/filesystem.ts
@@ -18,7 +18,7 @@ import {
   normalizeDriveRootPathForPlatform,
 } from '../services/windowsDrivePath.js'
 
-type FilesystemEntry = {
+export type FilesystemEntry = {
   name: string
   path: string
   isDirectory: boolean
@@ -189,15 +189,19 @@ async function handleBrowse(url: URL): Promise<Response> {
   }
 }
 
-async function searchFilesystemEntries(
+export async function searchFilesystemEntries(
   rootPath: string,
   searchQuery: string,
-  options: { includeFiles: boolean; maxResults: number },
+  options: { includeFiles: boolean; includeDirectories?: boolean; maxResults: number },
 ): Promise<FilesystemEntry[]> {
   const normalizedQuery = normalizeSearchText(searchQuery)
   if (!normalizedQuery) return []
 
-  const candidates = await getSearchCandidates(rootPath, options.includeFiles)
+  const candidates = await getSearchCandidates(
+    rootPath,
+    options.includeFiles,
+    options.includeDirectories ?? true,
+  )
   const results = candidates
     .map((entry): ScoredFilesystemEntry | null => {
       const relativePath = entry.relativePath ?? entry.name
@@ -221,7 +225,11 @@ async function searchFilesystemEntries(
     .map(({ score: _score, ...entry }) => entry)
 }
 
-async function getSearchCandidates(rootPath: string, includeFiles: boolean): Promise<FilesystemEntry[]> {
+async function getSearchCandidates(
+  rootPath: string,
+  includeFiles: boolean,
+  includeDirectories: boolean,
+): Promise<FilesystemEntry[]> {
   const files = await getProjectSearchFiles(rootPath)
   const entries = new Map<string, FilesystemEntry>()
 
@@ -229,12 +237,14 @@ async function getSearchCandidates(rootPath: string, includeFiles: boolean): Pro
     const normalizedFile = normalizeRelativePath(filePath)
     if (!normalizedFile || !isRelativeInsideRoot(normalizedFile)) continue
 
-    let currentDir = path.posix.dirname(normalizedFile)
-    while (currentDir !== '.') {
-      addCandidate(entries, rootPath, currentDir, true)
-      const parent = path.posix.dirname(currentDir)
-      if (parent === currentDir) break
-      currentDir = parent
+    if (includeDirectories) {
+      let currentDir = path.posix.dirname(normalizedFile)
+      while (currentDir !== '.') {
+        addCandidate(entries, rootPath, currentDir, true)
+        const parent = path.posix.dirname(currentDir)
+        if (parent === currentDir) break
+        currentDir = parent
+      }
     }
 
     if (includeFiles) {
diff --git a/src/server/api/sessions.ts b/src/server/api/sessions.ts
index 8cd2d508..4516bee9 100644
--- a/src/server/api/sessions.ts
+++ b/src/server/api/sessions.ts
@@ -46,6 +46,7 @@ import { findGitRoot } from '../../utils/git.js'
 import { traceCaptureService, trimTraceCallPreviews } from '../services/traceCaptureService.js'
 import { getSubagentRunByTool } from '../services/subagentRunService.js'
 import { isValidPermissionMode } from '../services/settingsService.js'
+import { handleWorkspaceSearchRoute } from './workspaceSearch.js'
 
 const DEFAULT_GIT_INFO_COMMAND_TIMEOUT_MS = 3_000
 
@@ -354,7 +355,7 @@ async function handleSessionWorkspaceRoute(
   url: URL,
   workspaceResource?: string,
 ): Promise<Response> {
-  await requireSessionWorkspace(sessionId)
+  const workDir = await requireSessionWorkspace(sessionId)
 
   switch (workspaceResource) {
     case 'status':
@@ -364,6 +365,8 @@ async function handleSessionWorkspaceRoute(
         sessionId,
         url.searchParams.get('path') || '',
       ))
+    case 'search':
+      return handleWorkspaceSearchRoute(workDir, url)
     case 'file':
       return await runWorkspaceRequest(() => workspaceService.readFile(
         sessionId,
diff --git a/src/server/api/workspaceSearch.test.ts b/src/server/api/workspaceSearch.test.ts
new file mode 100644
index 00000000..a36f8804
--- /dev/null
+++ b/src/server/api/workspaceSearch.test.ts
@@ -0,0 +1,76 @@
+import { afterEach, describe, expect, it } from 'bun:test'
+import { execFileSync } from 'node:child_process'
+import * as fsp from 'node:fs/promises'
+import * as os from 'node:os'
+import * as path from 'node:path'
+import { handleWorkspaceSearchRoute } from './workspaceSearch.js'
+
+const cleanupDirs = new Set<string>()
+
+afterEach(async () => {
+  for (const dir of cleanupDirs) {
+    await fsp.rm(dir, { recursive: true, force: true })
+  }
+  cleanupDirs.clear()
+})
+
+describe('workspace search API', () => {
+  it('finds a deeply nested Java class and returns workspace-relative paths', async () => {
+    const workDir = await fsp.mkdtemp(path.join(os.tmpdir(), 'workspace-search-test-'))
+    cleanupDirs.add(workDir)
+    execFileSync('git', ['init'], { cwd: workDir })
+    const relativePath = 'services/mental-health-service/src/main/java/com/example/campus/mentalhealth/controller/MentalHealthTrendController.java'
+    await fsp.mkdir(path.dirname(path.join(workDir, relativePath)), { recursive: true })
+    await fsp.writeFile(path.join(workDir, relativePath), 'final class MentalHealthTrendController {}')
+
+    const response = await handleWorkspaceSearchRoute(
+      workDir,
+      new URL('http://localhost/api/workspace/search?query=%20MentalHealthTrendController%20'),
+    )
+
+    expect(response.status).toBe(200)
+    expect(await response.json()).toEqual({
+      state: 'ok',
+      query: 'MentalHealthTrendController',
+      truncated: false,
+      entries: [{
+        name: 'MentalHealthTrendController.java',
+        path: relativePath,
+        isDirectory: false,
+      }],
+    })
+  })
+
+  it('rejects missing and blank queries', async () => {
+    for (const suffix of ['', '?query=%20%20']) {
+      expect(handleWorkspaceSearchRoute('/tmp/workspace', new URL(`http://localhost/search${suffix}`)))
+        .rejects.toMatchObject({ statusCode: 400 })
+    }
+  })
+
+  it('returns files in relevance order and reports when results are truncated', async () => {
+    const workDir = await fsp.mkdtemp(path.join(os.tmpdir(), 'workspace-search-limit-test-'))
+    cleanupDirs.add(workDir)
+    execFileSync('git', ['init'], { cwd: workDir })
+    const matchingDirectory = path.join(workDir, 'MatchingClassDirectory')
+    await fsp.mkdir(matchingDirectory, { recursive: true })
+    await Promise.all(Array.from({ length: 201 }, (_, index) => {
+      const fileName = `MatchingClass${String(index).padStart(3, '0')}.java`
+      return fsp.writeFile(path.join(matchingDirectory, fileName), `final class MatchingClass${index} {}`)
+    }))
+
+    const response = await handleWorkspaceSearchRoute(
+      workDir,
+      new URL('http://localhost/api/workspace/search?query=MatchingClass'),
+    )
+    const body = await response.json() as {
+      truncated: boolean
+      entries: Array<{ path: string; isDirectory: boolean }>
+    }
+
+    expect(body.truncated).toBe(true)
+    expect(body.entries).toHaveLength(200)
+    expect(body.entries.every((entry) => !entry.isDirectory)).toBe(true)
+    expect(body.entries[0]?.path).toBe('MatchingClassDirectory/MatchingClass000.java')
+  })
+})
diff --git a/src/server/api/workspaceSearch.ts b/src/server/api/workspaceSearch.ts
new file mode 100644
index 00000000..187379de
--- /dev/null
+++ b/src/server/api/workspaceSearch.ts
@@ -0,0 +1,30 @@
+import * as path from 'node:path'
+import { ApiError } from '../middleware/errorHandler.js'
+import { searchFilesystemEntries } from './filesystem.js'
+
+const WORKSPACE_SEARCH_RESULT_LIMIT = 200
+
+export async function handleWorkspaceSearchRoute(workDir: string, url: URL): Promise<Response> {
+  const query = url.searchParams.get('query')?.trim()
+  if (!query) {
+    throw ApiError.badRequest('query parameter is required for workspace search')
+  }
+
+  const entries = await searchFilesystemEntries(workDir, query, {
+    includeFiles: true,
+    includeDirectories: false,
+    maxResults: WORKSPACE_SEARCH_RESULT_LIMIT + 1,
+  })
+  const truncated = entries.length > WORKSPACE_SEARCH_RESULT_LIMIT
+
+  return Response.json({
+    state: 'ok',
+    query,
+    truncated,
+    entries: entries.slice(0, WORKSPACE_SEARCH_RESULT_LIMIT).map((entry) => ({
+      name: entry.name,
+      path: (entry.relativePath || path.relative(workDir, entry.path)).replace(/\\/g, '/'),
+      isDirectory: entry.isDirectory,
+    })),
+  })
+}