feat: start on a blank container — spawn with empty:true and no repo (skip clone, default worker image); Spawn UI enables blank spawn without repo selection

daemon/api.go

@@ -373,7 +373,13 @@ func (s *Server) handleSpawn(w http.ResponseWriter, r *http.Request) {
 	if !decodeBody(w, r, &body) {
 		return
 	}
-	if !validRepoPath(body.Repo) {
+	// Blank-container spawns carry no repo; everything else must look like
+	// group/project.
+	if body.Repo == "" && !body.Empty {
+		writeError(w, http.StatusBadRequest, "repo required (or set empty for a blank container)")
+		return
+	}
+	if body.Repo != "" && !validRepoPath(body.Repo) {
 		writeError(w, http.StatusBadRequest, "repo must look like group/project")
 		return
 	}

daemon/api_extra_test.go

@@ -682,3 +682,20 @@ func TestRenameAndSetModelBodyValidation(t *testing.T) {
 		t.Fatalf("bad model body = %d, want 400", code)
 	}
 }
+
+func TestAPISpawnBlankContainerNoRepo(t *testing.T) {
+	ts, _ := newSpawnAPIServer(t)
+
+	// no repo and not empty → 400
+	if code, body := apiReq(t, http.MethodPost, ts.URL+"/api/spawn", testToken, `{"repo":""}`); code != http.StatusBadRequest {
+		t.Fatalf("no-repo non-empty spawn = %d %s, want 400", code, body)
+	}
+	// blank container: no repo required
+	code, body := apiReq(t, http.MethodPost, ts.URL+"/api/spawn", testToken, `{"empty":true}`)
+	if code != http.StatusCreated {
+		t.Fatalf("blank spawn = %d %s, want 201", code, body)
+	}
+	if !strings.Contains(body, `"sessionId"`) {
+		t.Fatalf("blank spawn body = %s, want sessionId", body)
+	}
+}

daemon/docker.go

@@ -298,10 +298,13 @@ func (s *Spawner) runJob(repo, branch, model string, empty bool, sessionID strin
 	lock.Lock()
 	defer lock.Unlock()
 
+	// blank-container spawn: nothing to clone or update
+	if repo != "" {
 		if err := s.cloneOrUpdate(s.ctx, repo, branch, slug); err != nil {
 			s.setJob(sessionID, repo, stateError, "", err.Error())
 			return
 		}
+	}
 	s.setJob(sessionID, repo, stateBuilding, "", "")
 	if err := s.ensureImage(s.ctx); err != nil {
 		s.setJob(sessionID, repo, stateError, "", err.Error())

daemon/spawner_test.go

@@ -1348,3 +1348,24 @@ func TestSpawnerEmptyScratch(t *testing.T) {
 		t.Fatalf("sessions volume missing: %v", binds)
 	}
 }
+
+func TestSpawnerEmptyScratchNoRepo(t *testing.T) {
+	f := newFakeDocker()
+	sp, _ := newTestSpawner(t, f)
+
+	res, err := sp.Start(context.Background(), "", "", "", true)
+	if err != nil {
+		t.Fatalf("Start with no repo: %v", err)
+	}
+	waitJobState(t, sp, res.SessionID, stateRunning)
+	creates := f.createsByName("lvmh-agent-")
+	if len(creates) != 1 {
+		t.Fatalf("creates = %d, want 1", len(creates))
+	}
+	for _, b := range creates[0].HostConfig.Binds {
+		if b == "lvmh-sessions:/pi-sessions" || b == "lvmh-pi-cache:/root/.pi/agent/cache" {
+			continue
+		}
+		t.Fatalf("blank spawn must mount no repo volume: %v", creates[0].HostConfig.Binds)
+	}
+}

web/src/SpawnView.test.tsx

@@ -235,7 +235,11 @@ describe("SpawnView repo picker", () => {
 		render(tree(makeStore()));
 		await flush();
 		expect(screen.getByLabelText("Spawn container")).toBeDisabled();
-		expect(screen.getByText("select a repo above")).toBeInTheDocument();
+		expect(
+			screen.getByText(
+				"select a repo above — or tick “Empty container” for a blank workspace",
+			),
+		).toBeInTheDocument();
 	});
 });
 
@@ -739,4 +743,35 @@ describe("empty container spawn", () => {
 		await flush();
 		expect(bodies[0]).toContain('"empty":true');
 	});
+
+	it("blank container: spawn without selecting a repo", async () => {
+		const bodies: string[] = [];
+		mockFetchJson((url, init) => {
+			if (init?.method === "POST" && url.endsWith("/api/spawn")) {
+				bodies.push(String(init.body));
+				return { sessionId: "e2", imageUsed: "lvmh-worker:latest" };
+			}
+			if (url.endsWith("/api/gitlab/status"))
+				return { connected: true, baseUrl: "https://gl", username: "a" };
+			if (url.endsWith("/api/gitlab/repos")) return [repo("g/p")];
+			return [];
+		});
+		render(tree(makeStore()));
+		await flush();
+
+		// no repo selected: Spawn disabled
+		const spawnBtn = screen.getByLabelText(
+			"Spawn container",
+		) as HTMLButtonElement;
+		expect(spawnBtn.disabled).toBe(true);
+
+		fireEvent.click(screen.getByRole("checkbox"));
+		expect(spawnBtn.disabled).toBe(false);
+
+		fireEvent.click(spawnBtn);
+		await flush();
+		expect(bodies[0]).toContain('"empty":true');
+		expect(bodies[0]).toContain('"repo":""');
+		expect(bodies[0]).not.toContain('"branch"');
+	});
 });

web/src/SpawnView.tsx

@@ -41,9 +41,7 @@ function SpawnSteps({ state }: { state: string }): React.ReactNode {
 			{SPAWN_STEPS.map((step, i) => (
 				<span
 					key={step}
-					className={
+					className={idx > i ? "step done" : idx === i ? "step current" : "step"}
-						idx > i ? "step done" : idx === i ? "step current" : "step"
-					}
 					title={step}
 				/>
 			))}
@@ -167,15 +165,17 @@ export default function SpawnView({ store, pushToast }: Props) {
 		r.path.toLowerCase().includes(query.toLowerCase()),
 	);
 
-	// spawn is only reachable from the Spawn button, which is disabled until a
+	// spawn is reachable with a repo selected, or with the blank-container
-	// repo is selected.
+	// checkbox and no repo (empty workspace).
 	const spawn = async (): Promise<void> => {
 		setBusy(true);
 		setError("");
 		try {
 			const body = {
-				repo: selected!.path,
+				repo: selected?.path ?? "",
-				...(branch.trim().length > 0 ? { branch: branch.trim() } : {}),
+				...(selected !== null && branch.trim().length > 0
+					? { branch: branch.trim() }
+					: {}),
 				...(model.length > 0 ? { model } : {}),
 				...(empty ? { empty: true } : {}),
 			};
@@ -207,8 +207,7 @@ export default function SpawnView({ store, pushToast }: Props) {
 					const list = await store.refresh();
 					const s = list.find((x) => x.id === sessionId);
 					if (s !== undefined && s.online) {
-						if (timerRef.current !== null)
+						if (timerRef.current !== null) window.clearInterval(timerRef.current);
-							window.clearInterval(timerRef.current);
 						timerRef.current = null;
 						navigate(`/s/${sessionId}`);
 					}
@@ -236,7 +235,8 @@ export default function SpawnView({ store, pushToast }: Props) {
 				job.message !== undefined && job.message.length > 0
 					? ` (${job.message})`
 					: "";
-			return `${job.repo}: ${job.state}${detail}`;
+			const label = job.repo.length > 0 ? job.repo : "blank container";
+			return `${label}: ${job.state}${detail}`;
 		}
 		return "waiting for session to come online…";
 	};
@@ -246,9 +246,7 @@ export default function SpawnView({ store, pushToast }: Props) {
 			<div className="page">
 				<h1>Spawn</h1>
 				<p className="empty">
-					{error.length > 0
+					{error.length > 0 ? `gitlab status failed: ${error}` : "checking gitlab…"}
-						? `gitlab status failed: ${error}`
-						: "checking gitlab…"}
 				</p>
 			</div>
 		);
@@ -338,8 +336,7 @@ export default function SpawnView({ store, pushToast }: Props) {
 										<div style={{ minWidth: 0, flex: 1 }}>
 											<div className="repo-path">{r.path}</div>
 											<div className="repo-meta">
-												default {r.defaultBranch} ·{" "}
+												default {r.defaultBranch} · {r.lastActivityAt.slice(0, 10)}
-												{r.lastActivityAt.slice(0, 10)}
 											</div>
 										</div>
 										{reg !== undefined && (
@@ -364,8 +361,7 @@ export default function SpawnView({ store, pushToast }: Props) {
 											}}
 											onKeyDown={(e) => {
 												// let the native button handle Enter/Space
-												if (e.key === "Enter" || e.key === " ")
+												if (e.key === "Enter" || e.key === " ") e.stopPropagation();
-													e.stopPropagation();
 											}}
 										>
 											⚡ Prepare
@@ -390,29 +386,28 @@ export default function SpawnView({ store, pushToast }: Props) {
 							<button
 								type="button"
 								className="btn-primary"
-								disabled={selected === null || busy}
+								disabled={(selected === null && !empty) || busy}
 								aria-label="Spawn container"
 								onClick={() => void spawn()}
 							>
 								{busy ? "Spawning…" : "Spawn"}
 							</button>
 						</div>
-						{selected === null && (
+						{selected === null && !empty && (
 							<p className="repo-meta" style={{ marginTop: 8 }}>
-								select a repo above
+								select a repo above — or tick “Empty container” for a blank workspace
 							</p>
 						)}
 						{selected !== null && (
 							<p className="repo-meta" style={{ marginTop: 8 }}>
-								Will use:{" "}
+								Will use: {registration(selected.path)?.image ?? "base worker image"}
-								{registration(selected.path)?.image ?? "base worker image"}
 							</p>
 						)}
 						<div className="row" style={{ marginTop: 8 }}>
 							<select
 								aria-label="Initial model"
 								value={model}
-								disabled={selected === null}
+								disabled={selected === null && !empty}
 								onChange={(e) => setModel(e.target.value)}
 							>
 								<option value="">Default model (settings)</option>