diff --git a/packages/ui/src/sync/bootstrap.ts b/packages/ui/src/sync/bootstrap.ts
index caafc994..feb805d3 100644
--- a/packages/ui/src/sync/bootstrap.ts
+++ b/packages/ui/src/sync/bootstrap.ts
@@ -4,6 +4,36 @@ import type { GlobalState, State } from "./types"
 
 const cmp = (a: string, b: string) => (a < b ? -1 : a > b ? 1 : 0)
 
+/**
+ * SDK returns `{ data, error, response }` without throwing on non-2xx.
+ * The silent `x.data!` / `x.data ?? []` pattern lets HTTP 5xx warmup
+ * errors become empty state. Wrap into a real Error so retry() fires.
+ */
+function unwrap<T>(
+  result: { data?: T; error?: unknown; response?: { status?: number } },
+  name: string,
+): T {
+  if (result.error) {
+    const rawError = result.error
+    const status = result.response?.status
+    const message = typeof rawError === "object" && rawError !== null && "message" in rawError
+      ? String((rawError as { message?: unknown }).message)
+      : String(rawError)
+    const err = new Error(`${name} failed${status ? ` (${status})` : ""}: ${message}`)
+    if (status !== undefined) {
+      ;(err as Error & { status?: number }).status = status
+    }
+    throw err
+  }
+  if (result.data === undefined) {
+    // No error + no data: ambiguous, treat as transient so retry fires.
+    const err = new Error(`${name} returned no data`)
+    ;(err as Error & { status?: number }).status = 503
+    throw err
+  }
+  return result.data
+}
+
 const requestSignature = (items: Array<{ id: string }> | undefined): string => {
   if (!items || items.length === 0) return ""
   return items
@@ -37,18 +67,19 @@ export async function bootstrapGlobal(
   set: (patch: Partial<GlobalState>) => void,
 ) {
   const results = await Promise.allSettled([
-    retry(() => sdk.path.get().then((x) => set({ path: x.data! }))),
-    retry(() => sdk.global.config.get().then((x) => set({ config: x.data! }))),
+    retry(() => sdk.path.get().then((x) => set({ path: unwrap(x, "path.get") }))),
+    retry(() => sdk.global.config.get().then((x) => set({ config: unwrap(x, "global.config.get") }))),
     retry(() =>
       sdk.project.list().then((x) => {
-        const projects = (x.data ?? [])
+        const data = unwrap(x, "project.list")
+        const projects = data
           .filter((p): p is Project => !!p?.id)
           .filter((p) => !!p.worktree && !p.worktree.includes("opencode-test"))
           .sort((a, b) => cmp(a.id, b.id))
         set({ projects })
       }),
     ),
-    retry(() => sdk.provider.list().then((x) => set({ providers: x.data! }))),
+    retry(() => sdk.provider.list().then((x) => set({ providers: unwrap(x, "provider.list") }))),
   ])
 
   const errors = results
@@ -115,25 +146,30 @@ export async function bootstrapDirectory(input: {
   const results = await Promise.allSettled([
     seededProject
       ? Promise.resolve()
-      : retry(() => sdk.project.current().then((x) => set({ project: x.data!.id }))),
-    retry(() => sdk.provider.list().then((x) => set({ provider: x.data! }))),
-    retry(() => sdk.app.agents().then((x) => set({ agent: x.data ?? [] }))),
-    retry(() => sdk.config.get().then((x) => set({ config: x.data! }))),
+      : retry(() => sdk.project.current().then((x) => set({ project: unwrap(x, "project.current").id }))),
+    retry(() => sdk.provider.list().then((x) => set({ provider: unwrap(x, "provider.list") }))),
+    retry(() => sdk.app.agents().then((x) => set({ agent: unwrap(x, "app.agents") }))),
+    retry(() => sdk.config.get().then((x) => set({ config: unwrap(x, "config.get") }))),
     retry(() =>
       sdk.path.get().then((x) => {
-        set({ path: x.data! })
-        const next = projectID(x.data?.directory ?? directory, g.projects)
+        const data = unwrap(x, "path.get")
+        set({ path: data })
+        const next = projectID(data?.directory ?? directory, g.projects)
         if (next) set({ project: next })
       }),
     ),
-    retry(() => sdk.command.list().then((x) => set({ command: x.data ?? [] }))),
-    retry(() => sdk.session.status().then((x) => set({ session_status: x.data! }))),
+    retry(() => sdk.command.list().then((x) => set({ command: unwrap(x, "command.list") }))),
+    retry(() => sdk.session.status().then((x) => set({ session_status: unwrap(x, "session.status") }))),
     input.loadSessions(directory),
-    retry(() => sdk.mcp.status().then((x) => set({ mcp: x.data! }))),
-    retry(() => sdk.lsp.status().then((x) => set({ lsp: x.data! }))),
+    retry(() => sdk.mcp.status().then((x) => set({ mcp: unwrap(x, "mcp.status") }))),
+    retry(() => sdk.lsp.status().then((x) => set({ lsp: unwrap(x, "lsp.status") }))),
     retry(() =>
       sdk.vcs.get().then((x) => {
         const current = getState()
+        // vcs is optional — fall back to current if server omits it.
+        if (x.error) {
+          throw new Error(`vcs.get failed: ${String(x.error)}`)
+        }
         set({ vcs: x.data ?? current.vcs })
       }),
     ),
@@ -143,6 +179,12 @@ export async function bootstrapDirectory(input: {
         Object.entries(before.question ?? {}).map(([sessionID, questions]) => [sessionID, requestSignature(questions)]),
       )
       const x = await sdk.question.list(directory ? { directory } : undefined)
+        if (x.error) {
+          const status = (x as { response?: { status?: number } }).response?.status
+          const err = new Error(`question.list failed${status ? ` (${status})` : ""}: ${String(x.error)}`)
+          if (status !== undefined) (err as Error & { status?: number }).status = status
+          throw err
+        }
         const grouped = groupBySession(
           (x.data ?? []).filter((q): q is QuestionRequest => !!q?.id && !!q.sessionID),
         )
@@ -168,6 +210,12 @@ export async function bootstrapDirectory(input: {
         Object.entries(before.permission ?? {}).map(([sessionID, permissions]) => [sessionID, requestSignature(permissions)]),
       )
       const x = await sdk.permission.list(directory ? { directory } : undefined)
+        if (x.error) {
+          const status = (x as { response?: { status?: number } }).response?.status
+          const err = new Error(`permission.list failed${status ? ` (${status})` : ""}: ${String(x.error)}`)
+          if (status !== undefined) (err as Error & { status?: number }).status = status
+          throw err
+        }
         const grouped = groupBySession(
           (x.data ?? []).filter((perm): perm is PermissionRequest => !!perm?.id && !!perm?.sessionID),
         )