diff --git a/extensions/browser/src/browser-node-proxy.test.ts b/extensions/browser/src/browser-node-proxy.test.ts
new file mode 100644
index 000000000000..64a3b044a2fc
--- /dev/null
+++ b/extensions/browser/src/browser-node-proxy.test.ts
@@ -0,0 +1,307 @@
+// Browser tests cover independently bounded delegated node-proxy requests.
+import { MAX_TIMER_TIMEOUT_MS } from "openclaw/plugin-sdk/number-runtime";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+type BrowserNodeRequest = {
+  nodeId: string;
+  command: string;
+  timeoutMs: number;
+  idempotencyKey: string;
+  params: {
+    method: string;
+    path: string;
+    timeoutMs: number;
+    profile?: string;
+    errorEnvelope: string;
+  };
+};
+
+type BrowserNodeResponse = {
+  payload: { result: { ok: true; profile?: string } };
+};
+
+type BrowserGatewayCall = (
+  method: string,
+  options: { timeoutMs: number },
+  request: BrowserNodeRequest,
+  extra: { scopes: string[]; signal?: AbortSignal },
+) => Promise<BrowserNodeResponse>;
+
+const runtimeMocks = vi.hoisted(() => ({
+  callGatewayTool: vi.fn<BrowserGatewayCall>(),
+  persistBrowserProxyFiles: vi.fn<(_files?: unknown) => Promise<Map<string, string>>>(),
+  applyBrowserProxyPaths: vi.fn<(result: unknown, mapping: Map<string, string>) => void>(),
+  fetchBrowserJson: vi.fn<(...args: unknown[]) => Promise<unknown>>(),
+}));
+
+vi.mock("./browser-tool.runtime.js", () => runtimeMocks);
+
+import { createBrowserNodeProxyRequest } from "./browser-node-proxy.js";
+
+function createSessionProxy() {
+  return createBrowserNodeProxyRequest({
+    nodeTarget: { nodeId: "node-1" },
+    allowAutomaticHostFallback: false,
+  });
+}
+
+function readGatewayCall(index = 0) {
+  const call = runtimeMocks.callGatewayTool.mock.calls[index];
+  if (!call) {
+    throw new Error(`Expected Browser node invocation ${index}`);
+  }
+  const [method, gateway, node, extra] = call;
+  return { method, gateway, node, extra };
+}
+
+beforeEach(() => {
+  runtimeMocks.callGatewayTool.mockReset();
+  runtimeMocks.callGatewayTool.mockResolvedValue({ payload: { result: { ok: true } } });
+  runtimeMocks.persistBrowserProxyFiles.mockReset();
+  runtimeMocks.persistBrowserProxyFiles.mockResolvedValue(new Map<string, string>());
+  runtimeMocks.applyBrowserProxyPaths.mockReset();
+  runtimeMocks.fetchBrowserJson.mockReset();
+});
+
+describe("Browser node proxy nested watchdogs", () => {
+  it("keeps a requested action inside separate node and Gateway watchdogs", async () => {
+    const signal = new AbortController().signal;
+
+    await createSessionProxy()({
+      method: "GET",
+      path: "/snapshot",
+      profile: "work",
+      timeoutMs: 7_777,
+      signal,
+    });
+
+    const { method, gateway, node, extra } = readGatewayCall();
+    expect(method).toBe("node.invoke");
+    expect(node.nodeId).toBe("node-1");
+    expect(node.command).toBe("browser.proxy");
+    expect([node.params.timeoutMs, node.timeoutMs, gateway.timeoutMs]).toEqual([
+      7_777, 12_777, 17_777,
+    ]);
+    expect(node.params.errorEnvelope).toBe("browser-v1");
+    expect(extra).toEqual({ scopes: ["operator.admin"], signal });
+    expect(runtimeMocks.fetchBrowserJson).not.toHaveBeenCalled();
+  });
+
+  it("binds the tool execution signal to node requests without their own signal", async () => {
+    const signal = new AbortController().signal;
+    const proxy = createBrowserNodeProxyRequest({
+      nodeTarget: { nodeId: "node-1" },
+      allowAutomaticHostFallback: false,
+      signal,
+    });
+
+    await proxy({ method: "GET", path: "/snapshot" });
+
+    expect(readGatewayCall().extra).toEqual({ scopes: ["operator.admin"], signal });
+  });
+
+  it("keeps an explicit request signal ahead of the bound tool execution signal", async () => {
+    const toolSignal = new AbortController().signal;
+    const requestSignal = new AbortController().signal;
+    const proxy = createBrowserNodeProxyRequest({
+      nodeTarget: { nodeId: "node-1" },
+      allowAutomaticHostFallback: false,
+      signal: toolSignal,
+    });
+
+    await proxy({ method: "GET", path: "/snapshot", signal: requestSignal });
+
+    expect(readGatewayCall().extra).toEqual({
+      scopes: ["operator.admin"],
+      signal: requestSignal,
+    });
+  });
+
+  it("keeps the bound tool execution signal when a node falls back to the host", async () => {
+    const signal = new AbortController().signal;
+    runtimeMocks.callGatewayTool.mockRejectedValueOnce(
+      new Error("Browser control host is not reachable on 127.0.0.1:18791."),
+    );
+    runtimeMocks.fetchBrowserJson.mockResolvedValueOnce({ ok: true, source: "gateway-host" });
+    const proxy = createBrowserNodeProxyRequest({
+      nodeTarget: { nodeId: "node-1" },
+      allowAutomaticHostFallback: true,
+      signal,
+    });
+
+    await expect(proxy({ method: "GET", path: "/snapshot" })).resolves.toMatchObject({
+      ok: true,
+      source: "gateway-host",
+    });
+
+    expect(runtimeMocks.fetchBrowserJson).toHaveBeenCalledWith(
+      "/snapshot",
+      expect.objectContaining({ method: "GET", signal }),
+    );
+  });
+
+  it("keeps default action, node, and Gateway watchdogs strictly nested", async () => {
+    await createSessionProxy()({ method: "GET", path: "/snapshot" });
+
+    const { gateway, node } = readGatewayCall();
+    expect([node.params.timeoutMs, node.timeoutMs, gateway.timeoutMs]).toEqual([
+      20_000, 25_000, 30_000,
+    ]);
+  });
+
+  it.each([
+    Number.MAX_SAFE_INTEGER,
+    MAX_TIMER_TIMEOUT_MS,
+    MAX_TIMER_TIMEOUT_MS - 1,
+    MAX_TIMER_TIMEOUT_MS - 4_999,
+    MAX_TIMER_TIMEOUT_MS - 5_000,
+    MAX_TIMER_TIMEOUT_MS - 9_999,
+    MAX_TIMER_TIMEOUT_MS - 10_000,
+    MAX_TIMER_TIMEOUT_MS - 10_001,
+  ])("reserves both Node-safe watchdog windows for %i ms", async (timeoutMs) => {
+    await createSessionProxy()({ method: "GET", path: "/snapshot", timeoutMs });
+
+    const actionTimeoutMs = Math.min(timeoutMs, MAX_TIMER_TIMEOUT_MS - 10_000);
+    const { gateway, node } = readGatewayCall();
+    expect([node.params.timeoutMs, node.timeoutMs, gateway.timeoutMs]).toEqual([
+      actionTimeoutMs,
+      actionTimeoutMs + 5_000,
+      actionTimeoutMs + 10_000,
+    ]);
+    expect(gateway.timeoutMs).toBeLessThanOrEqual(MAX_TIMER_TIMEOUT_MS);
+  });
+
+  it("finishes ten independently owned, concurrently blocked Browser sessions", async () => {
+    let release!: () => void;
+    const barrier = new Promise<void>((resolve) => {
+      release = resolve;
+    });
+    runtimeMocks.callGatewayTool.mockImplementation(async (_method, _gateway, node) => {
+      await barrier;
+      return { payload: { result: { ok: true, profile: node.params.profile } } };
+    });
+
+    const sessions = Array.from({ length: 10 }, (_, index) => ({
+      profile: `session-${index}`,
+      timeoutMs: 7_777 + index,
+      signal: new AbortController().signal,
+      proxy: createSessionProxy(),
+    }));
+    const completed = new Set<string>();
+    const pending = sessions.map(async ({ profile, timeoutMs, signal, proxy }) => {
+      const result = await proxy({ method: "GET", path: "/snapshot", profile, timeoutMs, signal });
+      completed.add(profile);
+      return result;
+    });
+
+    try {
+      expect(runtimeMocks.callGatewayTool).toHaveBeenCalledTimes(10);
+      expect(completed.size).toBe(0);
+      expect(runtimeMocks.persistBrowserProxyFiles).not.toHaveBeenCalled();
+      const invocationIds = new Set<string>();
+
+      sessions.forEach(({ profile, timeoutMs, signal }, index) => {
+        const { method, gateway, node, extra } = readGatewayCall(index);
+        expect(method).toBe("node.invoke");
+        expect(node.nodeId).toBe("node-1");
+        expect(node.command).toBe("browser.proxy");
+        expect(node.params.profile).toBe(profile);
+        expect(node.params.errorEnvelope).toBe("browser-v1");
+        expect([node.params.timeoutMs, node.timeoutMs, gateway.timeoutMs]).toEqual([
+          timeoutMs,
+          timeoutMs + 5_000,
+          timeoutMs + 10_000,
+        ]);
+        expect(extra).toEqual({ scopes: ["operator.admin"], signal });
+        invocationIds.add(node.idempotencyKey);
+      });
+
+      expect(invocationIds.size).toBe(10);
+      expect(runtimeMocks.fetchBrowserJson).not.toHaveBeenCalled();
+    } finally {
+      release();
+    }
+
+    await expect(Promise.all(pending)).resolves.toEqual(
+      sessions.map(({ profile }) => ({ ok: true, profile })),
+    );
+    expect(completed.size).toBe(10);
+    expect(runtimeMocks.persistBrowserProxyFiles).toHaveBeenCalledTimes(10);
+    expect(runtimeMocks.applyBrowserProxyPaths).toHaveBeenCalledTimes(10);
+    expect(runtimeMocks.fetchBrowserJson).not.toHaveBeenCalled();
+    expect(sessions.every(({ proxy }) => !proxy.isHostFallbackActive())).toBe(true);
+  });
+
+  it("keeps one session cancellation isolated from nine concurrent sessions", async () => {
+    let release!: () => void;
+    const barrier = new Promise<void>((resolve) => {
+      release = resolve;
+    });
+    runtimeMocks.callGatewayTool.mockImplementation(
+      (_method, _gateway, node, extra) =>
+        new Promise<BrowserNodeResponse>((resolve, reject) => {
+          const onAbort = () => {
+            const reason = extra.signal?.reason;
+            reject(reason instanceof Error ? reason : new Error("Browser session cancelled"));
+          };
+          if (extra.signal?.aborted) {
+            onAbort();
+            return;
+          }
+          extra.signal?.addEventListener("abort", onAbort, { once: true });
+          void barrier.then(() => {
+            extra.signal?.removeEventListener("abort", onAbort);
+            if (!extra.signal?.aborted) {
+              resolve({ payload: { result: { ok: true, profile: node.params.profile } } });
+            }
+          });
+        }),
+    );
+
+    const sessions = Array.from({ length: 10 }, (_, index) => ({
+      profile: `session-${index}`,
+      timeoutMs: 7_777 + index,
+      controller: new AbortController(),
+      proxy: createSessionProxy(),
+    }));
+    const pending = sessions.map(({ profile, timeoutMs, controller, proxy }) =>
+      proxy({
+        method: "GET",
+        path: "/snapshot",
+        profile,
+        timeoutMs,
+        signal: controller.signal,
+      }),
+    );
+    const completion = Promise.allSettled(pending);
+    const cancelledSession = sessions.at(3);
+    const cancelledRun = pending.at(3);
+    if (!cancelledSession || !cancelledRun) {
+      release();
+      throw new Error("Expected a dedicated cancellation session");
+    }
+    const abortError = new Error("session-3 cancelled");
+
+    try {
+      expect(runtimeMocks.callGatewayTool).toHaveBeenCalledTimes(10);
+      cancelledSession.controller.abort(abortError);
+      await expect(cancelledRun).rejects.toBe(abortError);
+      expect(runtimeMocks.persistBrowserProxyFiles).not.toHaveBeenCalled();
+      expect(runtimeMocks.fetchBrowserJson).not.toHaveBeenCalled();
+    } finally {
+      release();
+    }
+
+    await expect(completion).resolves.toEqual(
+      sessions.map(({ profile }, index) =>
+        index === 3
+          ? { status: "rejected", reason: abortError }
+          : { status: "fulfilled", value: { ok: true, profile } },
+      ),
+    );
+    expect(runtimeMocks.persistBrowserProxyFiles).toHaveBeenCalledTimes(9);
+    expect(runtimeMocks.applyBrowserProxyPaths).toHaveBeenCalledTimes(9);
+    expect(runtimeMocks.fetchBrowserJson).not.toHaveBeenCalled();
+    expect(sessions.every(({ proxy }) => !proxy.isHostFallbackActive())).toBe(true);
+  });
+});
diff --git a/extensions/browser/src/browser-node-proxy.ts b/extensions/browser/src/browser-node-proxy.ts
index 49dd1d844cce..7e1f90d46098 100644
--- a/extensions/browser/src/browser-node-proxy.ts
+++ b/extensions/browser/src/browser-node-proxy.ts
@@ -1,4 +1,9 @@
 import crypto from "node:crypto";
+import {
+  addTimerTimeoutGraceMs,
+  MAX_TIMER_TIMEOUT_MS,
+  resolveTimerTimeoutMs,
+} from "openclaw/plugin-sdk/number-runtime";
 import { createSubsystemLogger } from "openclaw/plugin-sdk/runtime-env";
 import { isBrowserControlHostUnavailableError } from "./browser-node-fallback.js";
 import {
@@ -65,11 +70,18 @@ async function callBrowserProxy(params: {
   profile?: string;
   signal?: AbortSignal;
 }): Promise<BrowserProxySuccess> {
-  const proxyTimeoutMs =
-    typeof params.timeoutMs === "number" && Number.isFinite(params.timeoutMs)
-      ? Math.max(1, Math.floor(params.timeoutMs))
-      : DEFAULT_BROWSER_PROXY_TIMEOUT_MS;
-  const gatewayTimeoutMs = proxyTimeoutMs + BROWSER_PROXY_GATEWAY_TIMEOUT_SLACK_MS;
+  // Reserve both watchdog windows before clamping so timer saturation cannot
+  // make an outer watchdog expire alongside the browser action.
+  const proxyTimeoutMs = Math.min(
+    resolveTimerTimeoutMs(params.timeoutMs, DEFAULT_BROWSER_PROXY_TIMEOUT_MS),
+    MAX_TIMER_TIMEOUT_MS - 2 * BROWSER_PROXY_GATEWAY_TIMEOUT_SLACK_MS,
+  );
+  const nodeInvokeTimeoutMs =
+    addTimerTimeoutGraceMs(proxyTimeoutMs, BROWSER_PROXY_GATEWAY_TIMEOUT_SLACK_MS) ??
+    proxyTimeoutMs;
+  const gatewayTimeoutMs =
+    addTimerTimeoutGraceMs(nodeInvokeTimeoutMs, BROWSER_PROXY_GATEWAY_TIMEOUT_SLACK_MS) ??
+    nodeInvokeTimeoutMs;
   let payload: { payload?: unknown; payloadJSON?: unknown } | null;
   try {
     payload = await callGatewayTool<{ payload?: unknown; payloadJSON?: unknown }>(
@@ -78,9 +90,9 @@ async function callBrowserProxy(params: {
       {
         nodeId: params.nodeId,
         command: "browser.proxy",
-        // node.invoke owns a separate watchdog from browser.proxy. Keep both
-        // bounded, with enough outer slack for the proxy result to cross back.
-        timeoutMs: gatewayTimeoutMs,
+        // Keep the browser action, node watchdog, and Gateway RPC on distinct
+        // budgets so a detailed node timeout can cross both outer boundaries.
+        timeoutMs: nodeInvokeTimeoutMs,
         params: {
           method: params.method,
           path: params.path,
@@ -136,17 +148,24 @@ async function callLocalBrowserControl(params: Parameters<BrowserProxyRequest>[0
 export function createBrowserNodeProxyRequest(params: {
   nodeTarget: { nodeId: string; label?: string };
   allowAutomaticHostFallback: boolean;
+  signal?: AbortSignal;
 }): BrowserProxyRequest {
   let hostFallbackActive = false;
   const dispatch = async (request: Parameters<BrowserProxyRequest>[0]) => {
+    // Bind cancellation once so every node action and its safe host fallback
+    // inherit their execution signal without overriding an explicit request.
+    const requestWithSignal =
+      request.signal || params.signal
+        ? { ...request, signal: request.signal ?? params.signal }
+        : request;
     if (hostFallbackActive) {
-      return await callLocalBrowserControl(request);
+      return await callLocalBrowserControl(requestWithSignal);
     }
     try {
       const proxy = await callBrowserProxy({
         nodeId: params.nodeTarget.nodeId,
         markControlHostUnavailable: params.allowAutomaticHostFallback,
-        ...request,
+        ...requestWithSignal,
       });
       const mapping = await persistBrowserProxyFiles(proxy.files);
       applyBrowserProxyPaths(proxy.result, mapping);
@@ -164,7 +183,7 @@ export function createBrowserNodeProxyRequest(params: {
       logger.warn(
         `browser node ${params.nodeTarget.label ?? params.nodeTarget.nodeId} control host unavailable; falling back to Gateway host`,
       );
-      return await callLocalBrowserControl(request);
+      return await callLocalBrowserControl(requestWithSignal);
     }
   };
   return Object.assign(dispatch, {
diff --git a/extensions/browser/src/browser-tool.test.ts b/extensions/browser/src/browser-tool.test.ts
index 64b1a91bddad..2cbd9e50cc79 100644
--- a/extensions/browser/src/browser-tool.test.ts
+++ b/extensions/browser/src/browser-tool.test.ts
@@ -532,6 +532,7 @@ function nodeInvokeCall(callIndex: number): {
     nodeId?: string;
     command?: string;
     timeoutMs?: number;
+    idempotencyKey?: string;
     params?: {
       method?: string;
       path?: string;
@@ -542,7 +543,7 @@ function nodeInvokeCall(callIndex: number): {
       body?: Record<string, unknown>;
     };
   };
-  extra?: { scopes?: string[] };
+  extra?: { scopes?: string[]; signal?: AbortSignal };
 } {
   const toolName = mockCallArg<string>(gatewayMocks.callGatewayTool, callIndex, 0);
   const options = mockCallArg<{ timeoutMs?: number }>(gatewayMocks.callGatewayTool, callIndex, 1);
@@ -550,6 +551,7 @@ function nodeInvokeCall(callIndex: number): {
     nodeId?: string;
     command?: string;
     timeoutMs?: number;
+    idempotencyKey?: string;
     params?: {
       method?: string;
       path?: string;
@@ -559,7 +561,7 @@ function nodeInvokeCall(callIndex: number): {
       body?: Record<string, unknown>;
     };
   }>(gatewayMocks.callGatewayTool, callIndex, 2);
-  const extra = mockCallArg<{ scopes?: string[] } | undefined>(
+  const extra = mockCallArg<{ scopes?: string[]; signal?: AbortSignal } | undefined>(
     gatewayMocks.callGatewayTool,
     callIndex,
     3,
@@ -572,6 +574,50 @@ function lastNodeInvokeCall(): ReturnType<typeof nodeInvokeCall> {
   return nodeInvokeCall(-1);
 }
 
+function blockBrowserNodeGateway(count = 1): () => void {
+  let release!: () => void;
+  const barrier = new Promise<void>((resolve) => {
+    release = resolve;
+  });
+
+  for (let index = 0; index < count; index += 1) {
+    gatewayMocks.callGatewayTool.mockImplementationOnce(
+      () =>
+        new Promise<Record<string, unknown>>((resolve, reject) => {
+          const { request, extra } = lastNodeInvokeCall();
+          const signal = extra?.signal;
+          const onAbort = () => {
+            const reason = signal?.reason;
+            reject(reason instanceof Error ? reason : new Error("Browser tool cancelled"));
+          };
+          if (signal?.aborted) {
+            onAbort();
+            return;
+          }
+          signal?.addEventListener("abort", onAbort, { once: true });
+          void barrier.then(() => {
+            signal?.removeEventListener("abort", onAbort);
+            if (!signal?.aborted) {
+              resolve({
+                ok: true,
+                payload: {
+                  result: {
+                    ok: true,
+                    running: true,
+                    profile: request.params?.profile,
+                    path: "/tmp/test.png",
+                  },
+                },
+              });
+            }
+          });
+        }),
+    );
+  }
+
+  return release;
+}
+
 describe("browser tool output schema", () => {
   it("accepts snapshot details", async () => {
     const tool = createBrowserTool();
@@ -673,7 +719,7 @@ describe("browser tool download actions", () => {
     });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(40_000);
+    expect(options.timeoutMs).toBe(45_000);
     expect(request.params?.path).toBe("/wait/download");
     expect(request.params?.timeoutMs).toBe(35_000);
     expect(request.params?.body).toEqual({
@@ -705,7 +751,7 @@ describe("browser tool download actions", () => {
     });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(130_000);
+    expect(options.timeoutMs).toBe(135_000);
     expect(request.params?.timeoutMs).toBe(125_000);
     expect(request.params?.path).toBe("/download");
     expect(request.params?.body).toMatchObject({ ref: "e12", path: "report.pdf" });
@@ -819,7 +865,7 @@ describe("browser tool snapshot maxChars", () => {
     await tool.execute?.("call-1", { action: "status", profile: "user", target: "node" });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(50_000);
+    expect(options.timeoutMs).toBe(55_000);
     expect(request.params?.method).toBe("GET");
     expect(request.params?.path).toBe("/");
     expect(request.params?.profile).toBe("user");
@@ -980,8 +1026,8 @@ describe("browser tool snapshot maxChars", () => {
 
     expect(gatewayMocks.callGatewayTool).toHaveBeenCalledWith(
       "node.invoke",
-      // proxy adds a 5_000 ms slack on top of the per-request timeout.
-      expect.objectContaining({ timeoutMs: 7777 + 5_000 }),
+      // The Gateway watchdog must also outlive the separate node watchdog.
+      expect.objectContaining({ timeoutMs: 7777 + 10_000 }),
       expect.objectContaining({
         command: "browser.proxy",
         params: expect.objectContaining({
@@ -1102,7 +1148,7 @@ describe("browser tool snapshot maxChars", () => {
     await tool.execute?.("call-1", { action: "status", target: "node" });
 
     const { options, request, extra } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(25_000);
+    expect(options.timeoutMs).toBe(30_000);
     expect(extra?.scopes).toEqual(["operator.admin"]);
     expect(request.nodeId).toBe("node-1");
     expect(request.command).toBe("browser.proxy");
@@ -1111,6 +1157,99 @@ describe("browser tool snapshot maxChars", () => {
     expect(browserClientMocks.browserStatus).not.toHaveBeenCalled();
   });
 
+  it.each([
+    { action: "status", path: "/" },
+    { action: "screenshot", path: "/screenshot" },
+  ])("cancels an actual blocked node-backed $action tool execution", async ({ action, path }) => {
+    mockSingleBrowserProxyNode();
+    const release = blockBrowserNodeGateway();
+    const controller = new AbortController();
+    const abortError = new Error(`${action} tool execution cancelled`);
+    const pending = createBrowserTool().execute!(
+      `cancel-node-${action}`,
+      { action, target: "node" },
+      controller.signal,
+    );
+
+    try {
+      await vi.waitFor(() => expect(gatewayMocks.callGatewayTool).toHaveBeenCalledTimes(1));
+      const { request, extra } = lastNodeInvokeCall();
+      expect(request.params?.path).toBe(path);
+      expect(extra?.signal).toBe(controller.signal);
+      controller.abort(abortError);
+      await expect(pending).rejects.toBe(abortError);
+      expect(toolCommonMocks.fetchBrowserJson).not.toHaveBeenCalled();
+    } finally {
+      release();
+    }
+  });
+
+  it("isolates one cancelled real Browser tool execution from nine blocked node sessions", async () => {
+    mockSingleBrowserProxyNode();
+    const release = blockBrowserNodeGateway(10);
+    const sessions = Array.from({ length: 10 }, (_, index) => ({
+      profile: `session-${index}`,
+      controller: new AbortController(),
+      tool: createBrowserTool(),
+    }));
+    const completed = new Set<string>();
+    const pending = sessions.map(({ profile, controller, tool }) =>
+      tool.execute!(
+        `browser-tool-${profile}`,
+        { action: "status", target: "node", profile },
+        controller.signal,
+      ).then((result) => {
+        completed.add(profile);
+        return result;
+      }),
+    );
+    const completion = Promise.allSettled(pending);
+    const cancelledSession = sessions.at(3);
+    const cancelledRun = pending.at(3);
+    if (!cancelledSession || !cancelledRun) {
+      release();
+      throw new Error("Expected a dedicated Browser tool cancellation session");
+    }
+    const abortError = new Error("Browser tool session-3 cancelled");
+
+    try {
+      await vi.waitFor(() => expect(gatewayMocks.callGatewayTool).toHaveBeenCalledTimes(10));
+      expect(completed.size).toBe(0);
+      const invocationIds = new Set<string>();
+      sessions.forEach(({ profile, controller }, index) => {
+        const { request, extra } = nodeInvokeCall(index);
+        expect(request.params?.path).toBe("/");
+        expect(request.params?.profile).toBe(profile);
+        expect(extra?.signal).toBe(controller.signal);
+        if (request.idempotencyKey) {
+          invocationIds.add(request.idempotencyKey);
+        }
+      });
+      expect(invocationIds.size).toBe(10);
+      cancelledSession.controller.abort(abortError);
+      await expect(cancelledRun).rejects.toBe(abortError);
+      expect(completed.size).toBe(0);
+      expect(toolCommonMocks.fetchBrowserJson).not.toHaveBeenCalled();
+    } finally {
+      release();
+    }
+
+    await expect(completion).resolves.toEqual(
+      sessions.map(({ profile }, index) =>
+        index === 3
+          ? { status: "rejected", reason: abortError }
+          : {
+              status: "fulfilled",
+              value: expect.objectContaining({
+                details: expect.objectContaining({ ok: true, profile }),
+              }),
+            },
+      ),
+    );
+    expect(completed.size).toBe(9);
+    expect(toolCommonMocks.fetchBrowserJson).not.toHaveBeenCalled();
+  });
+
   it("falls back to the Gateway host when an auto-selected node has no browser host", async () => {
     mockSingleBrowserProxyNode();
     gatewayMocks.callGatewayTool.mockRejectedValueOnce(
@@ -1420,7 +1559,7 @@ describe("browser tool snapshot maxChars", () => {
     await tool.execute?.("call-1", { action: "doctor", target: "node" });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(25_000);
+    expect(options.timeoutMs).toBe(30_000);
     expect(request.nodeId).toBe("node-1");
     expect(request.command).toBe("browser.proxy");
     expect(request.params?.method).toBe("GET");
@@ -1667,7 +1806,7 @@ describe("browser tool snapshot maxChars", () => {
 
     const { options, request } = lastNodeInvokeCall();
     const body = request.params?.body as { targetId?: string; timeoutMs?: number } | undefined;
-    expect(options.timeoutMs).toBe(17_345);
+    expect(options.timeoutMs).toBe(22_345);
     expect(request.params?.method).toBe("POST");
     expect(request.params?.path).toBe("/screenshot");
     expect(request.params?.timeoutMs).toBe(12_345);
@@ -1692,7 +1831,7 @@ describe("browser tool snapshot maxChars", () => {
 
     const { options, request } = lastNodeInvokeCall();
     const body = request.params?.body as { timeoutMs?: number } | undefined;
-    expect(options.timeoutMs).toBe(25_000);
+    expect(options.timeoutMs).toBe(30_000);
     expect(request.params?.timeoutMs).toBe(20_000);
     expect(body?.timeoutMs).toBe(20_000);
   });
@@ -1728,11 +1867,11 @@ describe("browser tool snapshot maxChars", () => {
 
     expect((result?.details as { refsFallback?: string } | undefined)?.refsFallback).toBe("role");
     const firstCall = nodeInvokeCall(0);
-    expect(firstCall.options.timeoutMs).toBe(25_000);
+    expect(firstCall.options.timeoutMs).toBe(30_000);
     expect(firstCall.request.params?.path).toBe("/snapshot");
     expect(firstCall.request.params?.query?.refs).toBe("aria");
     const secondCall = nodeInvokeCall(1);
-    expect(secondCall.options.timeoutMs).toBe(25_000);
+    expect(secondCall.options.timeoutMs).toBe(30_000);
     expect(secondCall.request.params?.path).toBe("/snapshot");
     expect(secondCall.request.params?.query?.refs).toBe("role");
   });
@@ -1753,7 +1892,7 @@ describe("browser tool snapshot maxChars", () => {
     });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(25_000);
+    expect(options.timeoutMs).toBe(30_000);
     expect(request.params?.timeoutMs).toBe(20_000);
   });
 
@@ -1778,7 +1917,7 @@ describe("browser tool snapshot maxChars", () => {
     await tool.execute?.("call-1", { action: "status", profile: "user" });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(50_000);
+    expect(options.timeoutMs).toBe(55_000);
     expect(request.nodeId).toBe("node-1");
     expect(request.command).toBe("browser.proxy");
     expect(request.params?.profile).toBe("user");
@@ -1829,7 +1968,7 @@ describe("browser tool snapshot maxChars", () => {
     await tool.execute?.("call-1", { action: "status", profile: "user", target: "node" });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(50_000);
+    expect(options.timeoutMs).toBe(55_000);
     expect(request.nodeId).toBe("node-1");
     expect(request.command).toBe("browser.proxy");
     expect(request.params?.profile).toBe("user");
@@ -1848,7 +1987,7 @@ describe("browser tool snapshot maxChars", () => {
     await tool.execute?.("call-1", { action: "status", profile: "user", node: "node-1" });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(50_000);
+    expect(options.timeoutMs).toBe(55_000);
     expect(request.nodeId).toBe("node-1");
     expect(request.command).toBe("browser.proxy");
     expect(request.params?.profile).toBe("user");
@@ -2515,7 +2654,7 @@ describe("browser tool act compatibility", () => {
     });
 
     const { options, request } = lastNodeInvokeCall();
-    expect(options.timeoutMs).toBe(75_000);
+    expect(options.timeoutMs).toBe(80_000);
     expect(request.params?.path).toBe("/act");
     expect(request.params?.body).toEqual({
       kind: "wait",
@@ -2551,7 +2690,7 @@ describe("browser tool act compatibility", () => {
     const { options, request } = lastNodeInvokeCall();
     expect(request.params?.timeoutMs).toBe(95_000);
     expect(request.timeoutMs).toBe(100_000);
-    expect(options.timeoutMs).toBe(100_000);
+    expect(options.timeoutMs).toBe(105_000);
   });
 
   it("rejects fractional act request timeouts before node proxy calls", async () => {
diff --git a/extensions/browser/src/browser-tool.ts b/extensions/browser/src/browser-tool.ts
index c3491eed05aa..525607fe5710 100644
--- a/extensions/browser/src/browser-tool.ts
+++ b/extensions/browser/src/browser-tool.ts
@@ -520,7 +520,7 @@ export function createBrowserTool(opts?: {
         opts?.allowHostControl !== false,
       );
       const proxyRequest = nodeTarget
-        ? createBrowserNodeProxyRequest({ nodeTarget, allowAutomaticHostFallback })
+        ? createBrowserNodeProxyRequest({ nodeTarget, allowAutomaticHostFallback, signal })
         : null;
       const toolTimeoutMs =
         requestedTimeoutMs ??