diff --git a/src/agents/bash-tools.exec-runtime.pty-fallback.test.ts b/src/agents/bash-tools.exec-runtime.pty-fallback.test.ts
new file mode 100644
index 00000000000..c59570f2f46
--- /dev/null
+++ b/src/agents/bash-tools.exec-runtime.pty-fallback.test.ts
@@ -0,0 +1,103 @@
+import { afterEach, beforeAll, beforeEach, expect, test, vi } from "vitest";
+import type { ManagedRun, SpawnInput } from "../process/supervisor/index.js";
+
+let listRunningSessions: typeof import("./bash-process-registry.js").listRunningSessions;
+let resetProcessRegistryForTests: typeof import("./bash-process-registry.js").resetProcessRegistryForTests;
+let runExecProcess: typeof import("./bash-tools.exec-runtime.js").runExecProcess;
+
+const { supervisorSpawnMock } = vi.hoisted(() => ({
+  supervisorSpawnMock: vi.fn(),
+}));
+
+vi.mock("../process/supervisor/index.js", () => ({
+  getProcessSupervisor: () => ({
+    spawn: supervisorSpawnMock,
+    cancel: vi.fn(),
+    cancelScope: vi.fn(),
+    reconcileOrphans: vi.fn(),
+    getRecord: vi.fn(),
+  }),
+}));
+
+function createSuccessfulRun(input: SpawnInput): ManagedRun {
+  input.onStdout?.("ok");
+  return {
+    runId: input.runId ?? "test-run",
+    pid: 1234,
+    startedAtMs: Date.now(),
+    stdin: {
+      write: vi.fn(),
+      end: vi.fn(),
+      destroy: vi.fn(),
+    },
+    cancel: vi.fn(),
+    wait: vi.fn(async () => ({
+      reason: "exit" as const,
+      exitCode: 0,
+      exitSignal: null,
+      durationMs: 1,
+      stdout: "",
+      stderr: "",
+      timedOut: false,
+      noOutputTimedOut: false,
+    })),
+  };
+}
+
+beforeAll(async () => {
+  ({ listRunningSessions, resetProcessRegistryForTests } =
+    await import("./bash-process-registry.js"));
+  ({ runExecProcess } = await import("./bash-tools.exec-runtime.js"));
+});
+
+beforeEach(() => {
+  supervisorSpawnMock.mockReset();
+});
+
+afterEach(() => {
+  resetProcessRegistryForTests();
+  vi.clearAllMocks();
+});
+
+function runPtyFallback(warnings: string[] = []) {
+  return runExecProcess({
+    command: "printf ok",
+    workdir: process.cwd(),
+    env: {},
+    usePty: true,
+    warnings,
+    maxOutput: 20_000,
+    pendingMaxOutput: 20_000,
+    notifyOnExit: false,
+    timeoutSec: 5,
+  });
+}
+
+test("exec falls back when PTY spawn fails", async () => {
+  supervisorSpawnMock
+    .mockRejectedValueOnce(new Error("pty spawn failed"))
+    .mockImplementationOnce(async (input: SpawnInput) => createSuccessfulRun(input));
+
+  const warnings: string[] = [];
+  const handle = await runPtyFallback(warnings);
+  const outcome = await handle.promise;
+
+  expect(outcome.status).toBe("completed");
+  expect(outcome.aggregated).toContain("ok");
+  expect(warnings.join("\n")).toContain("PTY spawn failed");
+  expect(supervisorSpawnMock).toHaveBeenNthCalledWith(1, expect.objectContaining({ mode: "pty" }));
+  expect(supervisorSpawnMock).toHaveBeenNthCalledWith(
+    2,
+    expect.objectContaining({ mode: "child" }),
+  );
+});
+
+test("exec cleans session state when PTY fallback spawn also fails", async () => {
+  supervisorSpawnMock
+    .mockRejectedValueOnce(new Error("pty spawn failed"))
+    .mockRejectedValueOnce(new Error("child fallback failed"));
+
+  await expect(runPtyFallback()).rejects.toThrow("child fallback failed");
+
+  expect(listRunningSessions()).toHaveLength(0);
+});
diff --git a/src/agents/bash-tools.exec.pty-fallback-failure.test.ts b/src/agents/bash-tools.exec.pty-fallback-failure.test.ts
deleted file mode 100644
index bc1e9761d98..00000000000
--- a/src/agents/bash-tools.exec.pty-fallback-failure.test.ts
+++ /dev/null
@@ -1,60 +0,0 @@
-import { afterEach, beforeAll, beforeEach, expect, test, vi } from "vitest";
-let createExecTool: typeof import("./bash-tools.exec.js").createExecTool;
-let listRunningSessions: typeof import("./bash-process-registry.js").listRunningSessions;
-let resetProcessRegistryForTests: typeof import("./bash-process-registry.js").resetProcessRegistryForTests;
-
-const { supervisorSpawnMock } = vi.hoisted(() => ({
-  supervisorSpawnMock: vi.fn(),
-}));
-
-const makeSupervisor = () => {
-  const noop = vi.fn();
-  return {
-    spawn: (...args: unknown[]) => supervisorSpawnMock(...args),
-    cancel: noop,
-    cancelScope: noop,
-    reconcileOrphans: noop,
-    getRecord: noop,
-  };
-};
-
-vi.mock("../process/supervisor/index.js", () => ({
-  getProcessSupervisor: () => makeSupervisor(),
-}));
-
-beforeAll(async () => {
-  ({ createExecTool } = await import("./bash-tools.exec.js"));
-  ({ listRunningSessions, resetProcessRegistryForTests } =
-    await import("./bash-process-registry.js"));
-});
-
-beforeEach(() => {
-  supervisorSpawnMock.mockReset();
-});
-
-afterEach(() => {
-  resetProcessRegistryForTests();
-  vi.clearAllMocks();
-});
-
-test("exec cleans session state when PTY fallback spawn also fails", async () => {
-  supervisorSpawnMock
-    .mockRejectedValueOnce(new Error("pty spawn failed"))
-    .mockRejectedValueOnce(new Error("child fallback failed"));
-
-  const tool = createExecTool({
-    allowBackground: false,
-    host: "gateway",
-    security: "full",
-    ask: "off",
-  });
-
-  await expect(
-    tool.execute("toolcall", {
-      command: "echo ok",
-      pty: true,
-    }),
-  ).rejects.toThrow("child fallback failed");
-
-  expect(listRunningSessions()).toHaveLength(0);
-});
diff --git a/src/agents/bash-tools.exec.pty-fallback.test.ts b/src/agents/bash-tools.exec.pty-fallback.test.ts
deleted file mode 100644
index 6a6b74f63bc..00000000000
--- a/src/agents/bash-tools.exec.pty-fallback.test.ts
+++ /dev/null
@@ -1,39 +0,0 @@
-import { afterEach, beforeAll, expect, test, vi } from "vitest";
-let createExecTool: typeof import("./bash-tools.exec.js").createExecTool;
-let resetProcessRegistryForTests: typeof import("./bash-process-registry.js").resetProcessRegistryForTests;
-
-vi.mock("@lydell/node-pty", () => ({
-  spawn: () => {
-    const err = new Error("spawn EBADF");
-    (err as NodeJS.ErrnoException).code = "EBADF";
-    throw err;
-  },
-}));
-
-beforeAll(async () => {
-  ({ createExecTool } = await import("./bash-tools.exec.js"));
-  ({ resetProcessRegistryForTests } = await import("./bash-process-registry.js"));
-});
-
-afterEach(() => {
-  resetProcessRegistryForTests();
-  vi.clearAllMocks();
-});
-
-test("exec falls back when PTY spawn fails", async () => {
-  const tool = createExecTool({
-    allowBackground: false,
-    host: "gateway",
-    security: "full",
-    ask: "off",
-  });
-  const result = await tool.execute("toolcall", {
-    command: "printf ok",
-    pty: true,
-  });
-
-  expect(result.details.status).toBe("completed");
-  const text = result.content?.find((item) => item.type === "text")?.text ?? "";
-  expect(text).toContain("ok");
-  expect(text).toContain("PTY spawn failed");
-});