feat: add browsable directory picker for new sessions and project switch

Users had to type an absolute server path on a phone keyboard to pick a
working directory (#49 "Choose project UIX"), and #57 reports that
only the default-drive project is ever discoverable. #52 already added
recents + client.project.list() as flat pickers, but there was still no
way to browse into subdirectories or discover paths the server hadn't
already indexed as a "project" — the only fallback was manual typing.

The opencode server already exposes a scoped filesystem-listing endpoint
(GET /file, handled in file.ts/handlers/file.ts) that resolves relative
to whatever directory the request is scoped to (header or query param) —
no new server endpoint is needed. Add file.list() to the mobile SDK
client and a new DirectoryBrowserSheet that lists subdirectories one
level at a time (via clientForDirectory(dir) + file.list({path: "."})),
supports "up" navigation, and a manual jump-to-path field. Wire it into
both the "new session" modal and the existing DirectorySwitcher, so
recents/manual entry remain available as a fallback alongside browsing.

Residual gap: there's still no "list available drives" API, so Windows
users with projects on D:, E:, etc. still need to type the drive root
once (it's then remembered via recents) — a full fix for #57 would need
a small server-side addition to enumerate mounted volumes.

app/(tabs)/index.tsx

@@ -22,7 +22,7 @@ import { useConnections } from "../../src/stores/connections"
 import { useCatalog } from "../../src/stores/catalog"
 import type BottomSheet from "@gorhom/bottom-sheet"
 import type { Session, Project } from "../../src/lib/sdk"
-import { DirectorySwitcher } from "../../src/components/chat"
+import { DirectorySwitcher, DirectoryBrowserSheet } from "../../src/components/chat"
 
 function formatTime(timestamp: number): string {
   const date = new Date(timestamp)
@@ -129,6 +129,11 @@ export default function SessionsScreen() {
   } = useConnections()
   const loadCatalog = useCatalog((s) => s.load)
   const dirSheetRef = useRef<BottomSheet>(null)
+  const browserSheetRef = useRef<BottomSheet>(null)
+  const [browseStartDir, setBrowseStartDir] = useState<string | null>(null)
+  // Shared folder browser is opened either to pick a directory for a new
+  // session, or to switch the active connection's directory.
+  const [browseMode, setBrowseMode] = useState<"create" | "switch">("create")
   const [refreshing, setRefreshing] = useState(false)
 
   // Fetch server-known projects when the new session modal opens
@@ -270,6 +275,27 @@ export default function SessionsScreen() {
     }
   }
 
+  const openBrowser = useCallback(
+    (startDir: string | null, mode: "create" | "switch") => {
+      setBrowseStartDir(startDir || serverHome || null)
+      setBrowseMode(mode)
+      browserSheetRef.current?.expand()
+    },
+    [serverHome],
+  )
+
+  const onBrowserSelect = useCallback(
+    (directory: string) => {
+      if (browseMode === "switch") {
+        handleSwitchDirectory(directory)
+        dirSheetRef.current?.close()
+      } else {
+        onCreateInDirectory(directory)
+      }
+    },
+    [browseMode, handleSwitchDirectory, onCreateInDirectory],
+  )
+
   const onFabPress = () => {
     // Quick create in current project
     onCreateSession()
@@ -478,6 +504,24 @@ export default function SessionsScreen() {
                 </>
               )}
 
+              {/* Browse the server's filesystem instead of typing a path */}
+              <TouchableOpacity
+                style={[styles.projectRow, isDark && styles.projectRowDark, { marginTop: 16 }]}
+                onPress={() =>
+                  openBrowser(currentProject?.path?.absolute || activeConnection?.directory || null, "create")
+                }
+                disabled={isCreating}
+              >
+                <Ionicons name="folder-open-outline" size={18} color={isDark ? "#8b5cf6" : "#6d28d9"} />
+                <View style={styles.projectRowContent}>
+                  <Text style={[styles.projectRowName, isDark && styles.textDark]}>Browse Folders…</Text>
+                  <Text style={[styles.projectRowPath, isDark && styles.metaDark]}>
+                    Explore the server's filesystem
+                  </Text>
+                </View>
+                <Ionicons name="chevron-forward" size={16} color={isDark ? "#666666" : "#999999"} />
+              </TouchableOpacity>
+
               {/* Manual path input fallback */}
               <Text style={[styles.modalLabel, isDark && styles.metaDark, { marginTop: 16 }]}>
                 Enter Path Manually
@@ -609,6 +653,19 @@ export default function SessionsScreen() {
         serverHome={serverHome}
         isDark={isDark}
         onSwitch={handleSwitchDirectory}
+        onBrowse={() =>
+          openBrowser(activeConnection?.directory || currentProject?.path?.absolute || null, "switch")
+        }
+      />
+
+      {/* Browsable folder picker — used for both "new session in..." and
+          "switch project directory" flows (see browseMode). */}
+      <DirectoryBrowserSheet
+        sheetRef={browserSheetRef}
+        startDirectory={browseStartDir}
+        clientForDirectory={clientForDirectory}
+        isDark={isDark}
+        onSelect={onBrowserSelect}
       />
     </View>
   )

src/components/chat/DirectoryBrowserSheet.tsx

@@ -0,0 +1,326 @@
+import { useCallback, useRef, useState } from "react"
+import { ActivityIndicator, StyleSheet, Text, TouchableOpacity, View } from "react-native"
+import { Ionicons } from "@expo/vector-icons"
+import BottomSheet, { BottomSheetBackdrop, BottomSheetFlatList, BottomSheetTextInput } from "@gorhom/bottom-sheet"
+import type { Client, FileEntry } from "../../lib/sdk"
+
+interface Props {
+  sheetRef: React.RefObject<BottomSheet | null>
+  // Directory to start browsing from whenever the sheet opens (project root, server home, etc).
+  startDirectory: string | null
+  // Builds a client rooted at an arbitrary absolute directory (see connections store).
+  clientForDirectory: (directory: string) => Client | null
+  isDark: boolean
+  // Called with the chosen absolute directory when the user taps "Use this folder".
+  onSelect: (directory: string) => void
+}
+
+// Absolute-path helpers. Server working directories can be POSIX (/a/b) or
+// Windows (C:\a\b, D:/a/b) since the mobile app can point at either kind of
+// opencode server, so both separators are handled.
+function stripTrailingSlash(dir: string): string {
+  return dir.replace(/[\\/]+$/, "") || dir
+}
+
+function parentOf(dir: string): string | null {
+  const trimmed = stripTrailingSlash(dir)
+  const lastSlash = Math.max(trimmed.lastIndexOf("/"), trimmed.lastIndexOf("\\"))
+  if (lastSlash < 0) return null
+  const head = trimmed.slice(0, lastSlash)
+  if (!head) return trimmed[0] === "\\" ? "\\" : "/" // reached posix root
+  if (/^[a-zA-Z]:$/.test(head)) return `${head}\\` // reached a windows drive root
+  return head
+}
+
+function nameOf(dir: string): string {
+  const trimmed = stripTrailingSlash(dir)
+  const lastSlash = Math.max(trimmed.lastIndexOf("/"), trimmed.lastIndexOf("\\"))
+  return lastSlash >= 0 ? trimmed.slice(lastSlash + 1) || trimmed : trimmed
+}
+
+export function DirectoryBrowserSheet({ sheetRef, startDirectory, clientForDirectory, isDark, onSelect }: Props) {
+  const [browseDir, setBrowseDir] = useState<string | null>(null)
+  const [entries, setEntries] = useState<FileEntry[]>([])
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+  const [jumpPath, setJumpPath] = useState("")
+  const loadToken = useRef(0)
+
+  const load = useCallback(
+    (dir: string) => {
+      const client = clientForDirectory(dir)
+      const token = ++loadToken.current
+      setLoading(true)
+      setError(null)
+      if (!client) {
+        setEntries([])
+        setLoading(false)
+        setError("No active connection")
+        return
+      }
+      client.file
+        .list({ path: "." })
+        .then((items) => {
+          if (loadToken.current !== token) return
+          setEntries(items.filter((item) => item.type === "directory"))
+        })
+        .catch((err) => {
+          if (loadToken.current !== token) return
+          setEntries([])
+          setError(err instanceof Error ? err.message : "Failed to list directory")
+        })
+        .finally(() => {
+          if (loadToken.current === token) setLoading(false)
+        })
+    },
+    [clientForDirectory],
+  )
+
+  const enter = useCallback(
+    (dir: string) => {
+      setBrowseDir(dir)
+      load(dir)
+    },
+    [load],
+  )
+
+  // Reset to the starting directory every time the sheet opens.
+  const handleSheetChange = useCallback(
+    (index: number) => {
+      if (index < 0) return
+      setJumpPath("")
+      if (startDirectory) enter(startDirectory)
+    },
+    [startDirectory, enter],
+  )
+
+  const goUp = useCallback(() => {
+    if (!browseDir) return
+    const parent = parentOf(browseDir)
+    if (!parent) return
+    enter(parent)
+  }, [browseDir, enter])
+
+  const goJump = useCallback(() => {
+    const dir = jumpPath.trim()
+    if (!dir) return
+    setJumpPath("")
+    enter(dir)
+  }, [jumpPath, enter])
+
+  const handleUseFolder = useCallback(() => {
+    if (!browseDir) return
+    onSelect(browseDir)
+    sheetRef.current?.close()
+  }, [browseDir, onSelect, sheetRef])
+
+  const canGoUp = !!browseDir && !!parentOf(browseDir)
+
+  return (
+    <BottomSheet
+      ref={sheetRef}
+      index={-1}
+      snapPoints={["65%", "92%"]}
+      enablePanDownToClose
+      keyboardBehavior="interactive"
+      keyboardBlurBehavior="restore"
+      android_keyboardInputMode="adjustResize"
+      backgroundStyle={isDark ? s.sheetDark : s.sheet}
+      handleIndicatorStyle={{ backgroundColor: isDark ? "#666666" : "#cccccc" }}
+      backdropComponent={(props) => (
+        <BottomSheetBackdrop {...props} disappearsOnIndex={-1} appearsOnIndex={0} opacity={0.5} />
+      )}
+      onChange={handleSheetChange}
+    >
+      <View style={s.header}>
+        <Text style={[s.title, isDark && s.white]}>Browse Folders</Text>
+        <View style={s.pathRow}>
+          <TouchableOpacity onPress={goUp} disabled={!canGoUp} hitSlop={8}>
+            <Ionicons
+              name="arrow-up-circle-outline"
+              size={22}
+              color={canGoUp ? (isDark ? "#8b5cf6" : "#6d28d9") : isDark ? "#3a3a3a" : "#dddddd"}
+            />
+          </TouchableOpacity>
+          <Text style={[s.path, isDark && s.dimDark]} numberOfLines={1} ellipsizeMode="head">
+            {browseDir || "…"}
+          </Text>
+        </View>
+      </View>
+
+      <View style={s.inputWrap}>
+        <BottomSheetTextInput
+          style={[s.input, isDark && s.inputDark]}
+          placeholder="Jump to path..."
+          placeholderTextColor={isDark ? "#666666" : "#999999"}
+          value={jumpPath}
+          onChangeText={setJumpPath}
+          onSubmitEditing={goJump}
+          returnKeyType="go"
+          autoCapitalize="none"
+          autoCorrect={false}
+        />
+        {jumpPath.trim() && (
+          <TouchableOpacity style={[s.goBtn, isDark && s.goBtnDark]} onPress={goJump}>
+            <Ionicons name="arrow-forward" size={18} color={isDark ? "#0a0a0a" : "#ffffff"} />
+          </TouchableOpacity>
+        )}
+      </View>
+
+      <BottomSheetFlatList
+        data={entries}
+        keyExtractor={(item: FileEntry) => item.absolute}
+        renderItem={({ item }: { item: FileEntry }) => (
+          <TouchableOpacity style={[s.row, isDark && s.rowDark]} onPress={() => enter(item.absolute)}>
+            <Ionicons
+              name="folder-outline"
+              size={20}
+              color={item.ignored ? (isDark ? "#555555" : "#bbbbbb") : isDark ? "#888888" : "#666666"}
+            />
+            <Text style={[s.rowLabel, isDark && s.white, item.ignored && s.rowLabelDim]} numberOfLines={1}>
+              {item.name}
+            </Text>
+            <Ionicons name="chevron-forward" size={16} color={isDark ? "#555555" : "#cccccc"} />
+          </TouchableOpacity>
+        )}
+        contentContainerStyle={s.list}
+        ListHeaderComponent={
+          loading ? (
+            <View style={s.centerBox}>
+              <ActivityIndicator color={isDark ? "#ffffff" : "#0a0a0a"} />
+            </View>
+          ) : error ? (
+            <View style={s.centerBox}>
+              <Text style={s.errorText}>{error}</Text>
+            </View>
+          ) : null
+        }
+        ListEmptyComponent={
+          !loading && !error ? <Text style={[s.emptyText, isDark && s.dimDark]}>No subfolders here</Text> : null
+        }
+      />
+
+      <View style={s.footer}>
+        <TouchableOpacity
+          style={[s.selectBtn, isDark && s.selectBtnDark, !browseDir && s.selectBtnDisabled]}
+          onPress={handleUseFolder}
+          disabled={!browseDir}
+        >
+          <Ionicons name="checkmark-circle" size={18} color={isDark ? "#0a0a0a" : "#ffffff"} />
+          <Text style={[s.selectBtnText, isDark && s.selectBtnTextDark]} numberOfLines={1}>
+            Use {browseDir ? nameOf(browseDir) : "this folder"}
+          </Text>
+        </TouchableOpacity>
+      </View>
+    </BottomSheet>
+  )
+}
+
+const s = StyleSheet.create({
+  sheet: { backgroundColor: "#ffffff" },
+  sheetDark: { backgroundColor: "#1a1a1a" },
+  header: { paddingHorizontal: 16, paddingBottom: 8, gap: 8 },
+  title: { fontSize: 18, fontWeight: "700", color: "#0a0a0a" },
+  white: { color: "#ffffff" },
+  pathRow: {
+    flexDirection: "row",
+    alignItems: "center",
+    gap: 8,
+  },
+  path: {
+    flex: 1,
+    fontSize: 12,
+    color: "#666666",
+  },
+  dimDark: { color: "#888888" },
+  inputWrap: {
+    flexDirection: "row",
+    alignItems: "center",
+    paddingHorizontal: 16,
+    paddingBottom: 8,
+    gap: 8,
+  },
+  input: {
+    flex: 1,
+    height: 40,
+    borderRadius: 10,
+    paddingHorizontal: 12,
+    backgroundColor: "#f5f5f5",
+    color: "#0a0a0a",
+    fontSize: 14,
+  },
+  inputDark: {
+    backgroundColor: "#2a2a2a",
+    color: "#ffffff",
+  },
+  goBtn: {
+    width: 40,
+    height: 40,
+    borderRadius: 10,
+    backgroundColor: "#0a0a0a",
+    alignItems: "center",
+    justifyContent: "center",
+  },
+  goBtnDark: { backgroundColor: "#ffffff" },
+  list: {
+    paddingHorizontal: 16,
+    paddingBottom: 8,
+  },
+  row: {
+    flexDirection: "row",
+    alignItems: "center",
+    gap: 12,
+    paddingHorizontal: 14,
+    paddingVertical: 11,
+    borderRadius: 10,
+    backgroundColor: "#f5f5f5",
+    marginBottom: 6,
+  },
+  rowDark: { backgroundColor: "#2a2a2a" },
+  rowLabel: {
+    flex: 1,
+    fontSize: 14,
+    fontWeight: "600",
+    color: "#0a0a0a",
+  },
+  rowLabelDim: { color: "#999999" },
+  centerBox: {
+    paddingVertical: 24,
+    alignItems: "center",
+  },
+  errorText: {
+    fontSize: 13,
+    color: "#ef4444",
+    textAlign: "center",
+    paddingHorizontal: 16,
+  },
+  emptyText: {
+    fontSize: 13,
+    color: "#999999",
+    textAlign: "center",
+    paddingVertical: 24,
+  },
+  footer: {
+    paddingHorizontal: 16,
+    paddingVertical: 12,
+    borderTopWidth: StyleSheet.hairlineWidth,
+    borderTopColor: "#e5e5e5",
+  },
+  selectBtn: {
+    flexDirection: "row",
+    alignItems: "center",
+    justifyContent: "center",
+    gap: 8,
+    height: 46,
+    borderRadius: 12,
+    backgroundColor: "#0a0a0a",
+  },
+  selectBtnDark: { backgroundColor: "#ffffff" },
+  selectBtnDisabled: { opacity: 0.5 },
+  selectBtnText: {
+    fontSize: 15,
+    fontWeight: "600",
+    color: "#ffffff",
+  },
+  selectBtnTextDark: { color: "#0a0a0a" },
+})

src/components/chat/DirectorySwitcher.tsx

@@ -10,9 +10,12 @@ interface Props {
   serverHome: string | null
   isDark: boolean
   onSwitch: (directory?: string) => void
+  // Opens a browsable folder picker rooted at the server's filesystem, as an
+  // alternative to typing a path. Optional so existing callers keep working.
+  onBrowse?: () => void
 }
 
-export function DirectorySwitcher({ sheetRef, current, recents, serverHome, isDark, onSwitch }: Props) {
+export function DirectorySwitcher({ sheetRef, current, recents, serverHome, isDark, onSwitch, onBrowse }: Props) {
   const [custom, setCustom] = useState("")
 
   const handleSelect = useCallback(
@@ -100,14 +103,30 @@ export function DirectorySwitcher({ sheetRef, current, recents, serverHome, isDa
       </View>
 
       {/* Quick path chips */}
-      {serverHome && (
+      {(serverHome || onBrowse) && (
         <View style={s.chips}>
-          <TouchableOpacity style={[s.chip, isDark && s.chipDark]} onPress={() => setCustom(serverHome)}>
+          {serverHome && (
-            <Text style={[s.chipText, isDark && s.chipTextDark]}>~</Text>
+            <>
-          </TouchableOpacity>
+              <TouchableOpacity style={[s.chip, isDark && s.chipDark]} onPress={() => setCustom(serverHome)}>
-          <TouchableOpacity style={[s.chip, isDark && s.chipDark]} onPress={() => setCustom(serverHome + "/")}>
+                <Text style={[s.chipText, isDark && s.chipTextDark]}>~</Text>
-            <Text style={[s.chipText, isDark && s.chipTextDark]}>~/</Text>
+              </TouchableOpacity>
-          </TouchableOpacity>
+              <TouchableOpacity style={[s.chip, isDark && s.chipDark]} onPress={() => setCustom(serverHome + "/")}>
+                <Text style={[s.chipText, isDark && s.chipTextDark]}>~/</Text>
+              </TouchableOpacity>
+            </>
+          )}
+          {onBrowse && (
+            <TouchableOpacity
+              style={[s.chip, s.chipBrowse, isDark && s.chipDark]}
+              onPress={() => {
+                sheetRef.current?.close()
+                onBrowse()
+              }}
+            >
+              <Ionicons name="folder-open-outline" size={14} color={isDark ? "#8b5cf6" : "#6d28d9"} />
+              <Text style={[s.chipText, isDark && s.chipTextDark]}>Browse…</Text>
+            </TouchableOpacity>
+          )}
         </View>
       )}
 
@@ -188,6 +207,11 @@ const s = StyleSheet.create({
   chipDark: {
     backgroundColor: "#2a2040",
   },
+  chipBrowse: {
+    flexDirection: "row",
+    alignItems: "center",
+    gap: 4,
+  },
   chipText: {
     fontSize: 13,
     fontWeight: "600",

src/components/chat/index.ts

@@ -9,4 +9,5 @@ export { SlashPopover, type SlashCommand } from "./SlashPopover"
 export { ModelPicker } from "./ModelPicker"
 export { ImageAttachments, type Attachment } from "./ImageAttachments"
 export { DirectorySwitcher } from "./DirectorySwitcher"
+export { DirectoryBrowserSheet } from "./DirectoryBrowserSheet"
 export { SessionInfo } from "./SessionInfo"

src/lib/sdk.ts

@@ -143,6 +143,14 @@ export interface Project {
   }
 }
 
+export interface FileEntry {
+  name: string
+  path: string
+  absolute: string
+  type: "file" | "directory"
+  ignored: boolean
+}
+
 export interface Event {
   type: string
   properties: Record<string, unknown>
@@ -250,6 +258,17 @@ export function createClient(config: ClientConfig) {
       current: () => request<Project>(config, "/project/current"),
     },
 
+    // Server-side filesystem browsing, scoped to this client's directory
+    // (see ClientConfig.directory / x-opencode-directory header). Use
+    // clientForDirectory(dir) to get a client rooted at a specific folder,
+    // then list("." ) to enumerate its immediate children.
+    file: {
+      list: (params: { path?: string } = {}) => {
+        const query = new URLSearchParams({ path: params.path ?? "." })
+        return request<FileEntry[]>(config, `/file?${query.toString()}`)
+      },
+    },
+
     path: {
       get: () =>
         request<{ home: string; state: string; config: string; worktree: string; directory: string }>(config, "/path"),