diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0195b7a7d3..00bc45ceb8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,11 @@ file is the human-readable summary of what changed and why.
 
 ### Desktop / Web UI
 
+- **Switching to Work with no sandbox explains itself** — clicking **Work**
+  before you have a sandbox opens the Add sandbox dialog, which was a dialog
+  you did not ask for with nothing to say about why it appeared. It now leads
+  with the reason: Work requires a sandbox environment to run sessions.
+  Reaching the same dialog deliberately, from Settings, is unchanged.
 - **The CPU and memory fields explain themselves** — the Add sandbox dialog
   offered two unlabelled optional boxes with no hint of what a sandbox gets if
   you leave them empty, and the memory box ran past the edge of the dialog.
diff --git a/packages/app/src/i18n/en.ts b/packages/app/src/i18n/en.ts
index 49ea12586b..fa0b567b0d 100644
--- a/packages/app/src/i18n/en.ts
+++ b/packages/app/src/i18n/en.ts
@@ -379,6 +379,7 @@ export const dict = {
   "workspace.empty.none": "No sandbox yet. Create one to work in an isolated environment.",
   "workspace.empty.starting": "Your sandbox is not running yet. It appears here once it is ready.",
   "workspace.empty.stopped": "Your sandbox is stopped. Start it again from Settings → Servers.",
+  "sandbox.add.workIntro": "Work requires a sandbox environment to run sessions.",
   "sandbox.server.add": "Add sandbox",
   "sandbox.server.label": "Sandbox",
   "sandbox.server.menu.label": "Sandbox",
diff --git a/packages/app/src/i18n/es.ts b/packages/app/src/i18n/es.ts
index d064e3f931..ad1b43daa1 100644
--- a/packages/app/src/i18n/es.ts
+++ b/packages/app/src/i18n/es.ts
@@ -370,6 +370,7 @@ export const dict = {
   "workspace.empty.none": "Aún no hay ningún sandbox. Crea uno para trabajar en un entorno aislado.",
   "workspace.empty.starting": "Tu sandbox todavía no está en marcha. Aparecerá aquí cuando esté listo.",
   "workspace.empty.stopped": "Tu sandbox está detenido. Vuelve a iniciarlo desde Ajustes → Servidores.",
+  "sandbox.add.workIntro": "Trabajo requiere un entorno de sandbox para ejecutar sesiones.",
   "sandbox.server.add": "Añadir sandbox",
   "sandbox.server.label": "Sandbox",
   "sandbox.server.menu.label": "Sandbox",
diff --git a/packages/app/src/sandbox/dialog-add.tsx b/packages/app/src/sandbox/dialog-add.tsx
index 80ea641738..9017cc7a6a 100644
--- a/packages/app/src/sandbox/dialog-add.tsx
+++ b/packages/app/src/sandbox/dialog-add.tsx
@@ -1,7 +1,14 @@
 import { useDialog } from "@opencode-ai/ui/context/dialog"
 import { showToast } from "@opencode-ai/ui/toast"
 import { ButtonV2 } from "@opencode-ai/ui/v2/button-v2"
-import { Dialog, DialogBody, DialogFooter, DialogHeader, DialogTitle } from "@opencode-ai/ui/v2/dialog-v2"
+import {
+  Dialog,
+  DialogBody,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+  DialogTitleGroup,
+} from "@opencode-ai/ui/v2/dialog-v2"
 import { DividerV2 } from "@opencode-ai/ui/v2/divider-v2"
 import { LoaderV2 } from "@opencode-ai/ui/v2/loader-v2"
 import { TextInputV2 } from "@opencode-ai/ui/v2/text-input-v2"
@@ -25,7 +32,13 @@ import {
 // need to react to a creation must use it rather than watching the sandbox
 // list: that list arrives over a separate IPC event, so it is still empty for
 // a beat after add() resolves.
-export function DialogAddSandbox(props: { onCreated?: (config: SandboxConfig) => void }) {
+export function DialogAddSandbox(props: {
+  onCreated?: (config: SandboxConfig) => void
+  // Set when the dialog opened because Work needs a sandbox and there is none,
+  // rather than because the user asked to add one. That dialog arrives
+  // unbidden, so it has to say why it is there.
+  requiredForWork?: boolean
+}) {
   const language = useLanguage()
   const platform = usePlatform()
   const dialog = useDialog()
@@ -193,7 +206,19 @@ export function DialogAddSandbox(props: { onCreated?: (config: SandboxConfig) =>
   return (
     <Dialog fit>
       <DialogHeader hideClose={true}>
-        <DialogTitle>{language.t("sandbox.server.add")}</DialogTitle>
+        {/* As a description under the title rather than a line in the body:
+            it explains the whole dialog, not the field it happens to sit
+            above, and DialogTitleGroup ties it to the dialog for screen
+            readers. */}
+        <Show
+          when={props.requiredForWork}
+          fallback={<DialogTitle>{language.t("sandbox.server.add")}</DialogTitle>}
+        >
+          <DialogTitleGroup
+            title={language.t("sandbox.server.add")}
+            description={language.t("sandbox.add.workIntro")}
+          />
+        </Show>
       </DialogHeader>
       <DividerV2 />
       <DialogBody class="flex flex-col gap-3 px-4 pt-3 pb-1">
diff --git a/packages/app/src/workspace/tabs.tsx b/packages/app/src/workspace/tabs.tsx
index 446db5a5dc..dbd3b926e6 100644
--- a/packages/app/src/workspace/tabs.tsx
+++ b/packages/app/src/workspace/tabs.tsx
@@ -82,7 +82,7 @@ export function useWorkspaceSwitch() {
           // list arrives on a separate IPC event and is still empty for a beat
           // after the create resolves, so checking it here left the user on
           // Code until they toggled the tabs by hand.
-          void dialog.show(() => <module.DialogAddSandbox onCreated={() => enter("work")} />)
+          void dialog.show(() => <module.DialogAddSandbox requiredForWork onCreated={() => enter("work")} />)
         })
         return
       }