diff --git a/backend/src/bridge/session-bridge.ts b/backend/src/bridge/session-bridge.ts
index 830cade4..e7834b73 100644
--- a/backend/src/bridge/session-bridge.ts
+++ b/backend/src/bridge/session-bridge.ts
@@ -7,7 +7,10 @@ export type ClientEvent =
   | { type: "info"; [k: string]: any }
   | { type: "system_event"; [k: string]: any };
 
+export type TurnState = "idle" | "running" | "waiting" | "failed";
+
 export class SessionBridge {
+  private state: TurnState = "idle";
   private pending: any = null;
   // Pi (rpc-mode createDialogPromise) assegna a ogni ctx.ui.input un id RPC PROPRIO
   // (crypto.randomUUID) e correla extension_ui_response su quell'id — NON sull'id interno
@@ -23,7 +26,19 @@ export class SessionBridge {
         try { descriptor = JSON.parse(m.title as string); } catch { return; }
         this.pending = descriptor;
         this.pendingPiId = m.id as string | null;
+        this.state = "waiting";
         this.fan({ type: "ui_request", ui_request: descriptor });
+      } else if (
+        m.type === "message_end" &&
+        m.message?.role === "assistant" &&
+        m.message?.stopReason === "error"
+      ) {
+        this.state = "failed";
+        this.fan({
+          type: "info",
+          level: "error",
+          text: "Model request failed. Check provider connectivity, then Resume the session.",
+        });
       } else if (m.type === "extension_ui_request" && m.method === "notify") {
         this.fan({ type: "info", level: m.notifyType ?? "info", text: m.message ?? "" });
       } else if (m.type === "message_update" && m.assistantMessageEvent?.type === "text_delta") {
@@ -37,8 +52,10 @@ export class SessionBridge {
       } else if (m.type === "system_event") {
         this.fan(m as ClientEvent);
       } else if (m.type === "agent_end") {
+        if (this.state !== "failed" && !this.pending) this.state = "idle";
         this.fan({ type: "system_event", event: "agent_end" });
       } else if (m.type === "agent_start") {
+        this.state = "running";
         this.fan({ type: "system_event", event: "agent_start" });
       } else if (m.type === "turn_end") {
         this.fan({ type: "system_event", event: "turn_end" });
@@ -48,6 +65,10 @@ export class SessionBridge {
 
   private fan(e: ClientEvent) { for (const cb of this.cbs) cb(e); }
 
+  turnState(): TurnState { return this.state; }
+
+  beginTurn(): void { this.state = "running"; }
+
   onClientEvent(cb: (e: ClientEvent) => void): void { this.cbs.add(cb); }
 
   /** Eventi generati dal backend stesso (es. exit inatteso del child Pi), non da Pi. */
@@ -57,11 +78,15 @@ export class SessionBridge {
     // Correla sull'id RPC di Pi; `value` porta l'uiResponse (con l'id del descriptor) cosi'
     // il check interno del gate (resp.id === descriptor.id) regge.
     const piId = this.pendingPiId ?? uiResponse.id;
+    this.state = "running";
     this.rpc.send({ type: "extension_ui_response", id: piId, value: JSON.stringify(uiResponse) });
     if (this.pending && uiResponse.id === this.pending.id) { this.pending = null; this.pendingPiId = null; }
   }
 
-  steer(text: string): void { this.rpc.send({ type: "steer", message: text }); }
+  steer(text: string): void {
+    this.state = "running";
+    this.rpc.send({ type: "steer", message: text });
+  }
 
   pendingWidget(): object | null { return this.pending; }
 }
diff --git a/backend/src/pi/pi-process-manager.ts b/backend/src/pi/pi-process-manager.ts
index bfecedb1..7f6af95b 100644
--- a/backend/src/pi/pi-process-manager.ts
+++ b/backend/src/pi/pi-process-manager.ts
@@ -94,6 +94,7 @@ export class PiProcessManager {
     const rpc = new RpcClient(child);
     const bridge = new SessionBridge(rpc);
     const rt: SessionRuntime = { rpc, bridge, child };
+    bridge.beginTurn();
     this.runtimes.set(sessionId, rt);
     // Identity-checked: a stale child's exit must not evict a newer runtime.
     // Expected teardowns (teardown()/respawn) delete the runtime from the map BEFORE the
@@ -136,6 +137,7 @@ export class PiProcessManager {
     const message = o.mode === "resume"
       ? `/riprendi-sessione ${sessionId}`
       : `/nuova-domanda ${JSON.stringify(o.question ?? "")}`;
+    rt.bridge.beginTurn();
     rt.rpc.send({ type: "prompt", message });
   }
 
diff --git a/backend/test/pi-process-manager.test.ts b/backend/test/pi-process-manager.test.ts
index 5ffb179a..f10d6ce8 100644
--- a/backend/test/pi-process-manager.test.ts
+++ b/backend/test/pi-process-manager.test.ts
@@ -155,6 +155,34 @@ test("createFor does not prompt until start is called", async () => {
   mgr.teardown("sid-deferred");
 });
 
+test("a created runtime is active during configure/bootstrap", () => {
+  const child = recordingChild();
+  const mgr = new PiProcessManager(loadConfig({}), { spawnFn: () => child as any });
+  const runtime = mgr.createFor("starting-id", {});
+  expect(runtime.bridge.turnState()).toBe("running");
+  mgr.teardown("starting-id");
+});
+
+test("start reactivates the runtime before sending the prompt", () => {
+  const child = recordingChild();
+  const mgr = new PiProcessManager(loadConfig({}), { spawnFn: () => child as any });
+  const runtime = mgr.createFor("restart-id", {});
+  child.stdout.emit("data", `${JSON.stringify({ type: "agent_end", messages: [] })}\n`);
+  expect(runtime.bridge.turnState()).toBe("idle");
+  let stateAtWrite = runtime.bridge.turnState();
+  child.stdin.write = (data: unknown) => {
+    stateAtWrite = runtime.bridge.turnState();
+    child._writes.push(String(data));
+    return true;
+  };
+
+  mgr.start("restart-id", runtime, { question: "q" });
+
+  expect(stateAtWrite).toBe("running");
+  expect(runtime.bridge.turnState()).toBe("running");
+  mgr.teardown("restart-id");
+});
+
 test("production spawn uses explicit Pi path and passes portable data root without rewriting PATH", async () => {
   vi.stubEnv("PATH", "/usr/local/bin:/usr/bin");
   vi.stubEnv("PI_PROVIDER_API_KEY", "provider-secret");
diff --git a/backend/test/session-bridge.test.ts b/backend/test/session-bridge.test.ts
index 73d15d94..7069a1e6 100644
--- a/backend/test/session-bridge.test.ts
+++ b/backend/test/session-bridge.test.ts
@@ -42,6 +42,78 @@ test("real Pi thinking_delta becomes a dedicated activity_delta to the FE", () =
   expect(seen).toEqual([{ type: "activity_delta", text: "Valuto le ambiguità" }]);
 });
 
+test("assistant provider errors are sanitized and leave the turn failed", () => {
+  const { rpc, fire } = fakeRpc();
+  const bridge = new SessionBridge(rpc);
+  const seen: any[] = [];
+  bridge.onClientEvent((event) => seen.push(event));
+  bridge.beginTurn();
+
+  fire({
+    type: "message_end",
+    message: {
+      role: "assistant",
+      stopReason: "error",
+      errorMessage: "Connection failed for https://secret.invalid/?api_key=DO_NOT_LEAK",
+    },
+  });
+  fire({ type: "agent_end", messages: [] });
+
+  expect(bridge.turnState()).toBe("failed");
+  expect(seen).toContainEqual({
+    type: "info",
+    level: "error",
+    text: "Model request failed. Check provider connectivity, then Resume the session.",
+  });
+  expect(JSON.stringify(seen)).not.toContain("DO_NOT_LEAK");
+});
+
+test("reviewer wait and response transition waiting back to running", () => {
+  const { rpc, fire } = fakeRpc();
+  const bridge = new SessionBridge(rpc);
+  bridge.beginTurn();
+  fire({
+    type: "extension_ui_request",
+    id: "pi-1",
+    method: "input",
+    title: JSON.stringify({ id: "gate-1", widget: "select" }),
+  });
+  expect(bridge.turnState()).toBe("waiting");
+  bridge.respond({ id: "gate-1", choices: ["approve"] });
+  expect(bridge.turnState()).toBe("running");
+  fire({ type: "agent_end", messages: [] });
+  expect(bridge.turnState()).toBe("idle");
+});
+
+test("agent_start transitions an idle turn to running", () => {
+  const { rpc, fire } = fakeRpc();
+  const bridge = new SessionBridge(rpc);
+  const seen: any[] = [];
+  bridge.onClientEvent((event) => seen.push(event));
+
+  expect(bridge.turnState()).toBe("idle");
+  fire({ type: "agent_start" });
+
+  expect(bridge.turnState()).toBe("running");
+  expect(seen).toContainEqual({ type: "system_event", event: "agent_start" });
+});
+
+test("agent_end leaves a pending reviewer wait intact", () => {
+  const { rpc, fire } = fakeRpc();
+  const bridge = new SessionBridge(rpc);
+  bridge.beginTurn();
+  fire({
+    type: "extension_ui_request",
+    id: "pi-1",
+    method: "input",
+    title: JSON.stringify({ id: "gate-1", widget: "select" }),
+  });
+
+  fire({ type: "agent_end", messages: [] });
+
+  expect(bridge.turnState()).toBe("waiting");
+});
+
 test("extension_ui_request nativo (method:input, title=json) diventa ui_request col descriptor ed è il pendente", () => {
   const { rpc, fire } = fakeRpc();
   const b = new SessionBridge(rpc);
@@ -79,8 +151,20 @@ test("agent_end di Pi diventa un system_event agent_end per il FE", () => {
   expect(seen).toEqual([{ type: "system_event", event: "agent_end" }]);
 });
 
-test("steer invia un comando steer", () => {
-  const { rpc, sent } = fakeRpc();
-  new SessionBridge(rpc).steer("considera solo il 2024");
+test("steer invia un comando steer e riattiva il turno", () => {
+  const { rpc, sent, fire } = fakeRpc();
+  const bridge = new SessionBridge(rpc);
+  bridge.beginTurn();
+  fire({
+    type: "extension_ui_request",
+    id: "pi-1",
+    method: "input",
+    title: JSON.stringify({ id: "gate-1", widget: "select" }),
+  });
+  expect(bridge.turnState()).toBe("waiting");
+
+  bridge.steer("considera solo il 2024");
+
   expect(sent.at(-1)).toEqual({ type: "steer", message: "considera solo il 2024" });
+  expect(bridge.turnState()).toBe("running");
 });