diff --git a/src/cli/acp-cli.option-collisions.test.ts b/src/cli/acp-cli.option-collisions.test.ts
index 068f415de79..820467ba5a4 100644
--- a/src/cli/acp-cli.option-collisions.test.ts
+++ b/src/cli/acp-cli.option-collisions.test.ts
@@ -7,7 +7,10 @@ const runAcpClientInteractive = vi.fn(async (_opts: unknown) => {});
 const serveAcpGateway = vi.fn(async (_opts: unknown) => {});
 
 const defaultRuntime = {
+  log: vi.fn(),
   error: vi.fn(),
+  writeStdout: vi.fn(),
+  writeJson: vi.fn(),
   exit: vi.fn(),
 };
 
@@ -52,7 +55,10 @@ describe("acp cli option collisions", () => {
   beforeEach(() => {
     runAcpClientInteractive.mockClear();
     serveAcpGateway.mockClear();
+    defaultRuntime.log.mockClear();
     defaultRuntime.error.mockClear();
+    defaultRuntime.writeStdout.mockClear();
+    defaultRuntime.writeJson.mockClear();
     defaultRuntime.exit.mockClear();
   });
 
diff --git a/src/cli/browser-cli-inspect.test.ts b/src/cli/browser-cli-inspect.test.ts
index 14a0b2f3be9..a58d83614a4 100644
--- a/src/cli/browser-cli-inspect.test.ts
+++ b/src/cli/browser-cli-inspect.test.ts
@@ -50,6 +50,12 @@ vi.mock("./browser-cli-shared.js", () => ({
 const runtime = {
   log: vi.fn(),
   error: vi.fn(),
+  writeStdout: vi.fn((value: string) => {
+    runtime.log(value.endsWith("\n") ? value.slice(0, -1) : value);
+  }),
+  writeJson: vi.fn((value: unknown, space = 2) => {
+    runtime.log(JSON.stringify(value, null, space));
+  }),
   exit: vi.fn(),
 };
 vi.mock("../runtime.js", () => ({
diff --git a/src/cli/browser-cli-manage.test.ts b/src/cli/browser-cli-manage.test.ts
index 86c10ac75ae..c4d7a36ffa3 100644
--- a/src/cli/browser-cli-manage.test.ts
+++ b/src/cli/browser-cli-manage.test.ts
@@ -20,6 +20,12 @@ const mocks = vi.hoisted(() => {
     runtime: {
       log: runtimeLog,
       error: runtimeError,
+      writeStdout: vi.fn((value: string) =>
+        runtimeLog(value.endsWith("\n") ? value.slice(0, -1) : value),
+      ),
+      writeJson: vi.fn((value: unknown, space = 2) =>
+        runtimeLog(JSON.stringify(value, null, space)),
+      ),
       exit: runtimeExit,
     },
   };
diff --git a/src/cli/browser-cli-manage.timeout-option.test.ts b/src/cli/browser-cli-manage.timeout-option.test.ts
index 7338d97701e..d52341a37da 100644
--- a/src/cli/browser-cli-manage.timeout-option.test.ts
+++ b/src/cli/browser-cli-manage.timeout-option.test.ts
@@ -28,6 +28,12 @@ const mocks = vi.hoisted(() => {
     runtime: {
       log: runtimeLog,
       error: runtimeError,
+      writeStdout: vi.fn((value: string) =>
+        runtimeLog(value.endsWith("\n") ? value.slice(0, -1) : value),
+      ),
+      writeJson: vi.fn((value: unknown, space = 2) =>
+        runtimeLog(JSON.stringify(value, null, space)),
+      ),
       exit: runtimeExit,
     },
   };
diff --git a/src/cli/browser-cli-state.option-collisions.test.ts b/src/cli/browser-cli-state.option-collisions.test.ts
index 2fb445c6af7..4980abc2993 100644
--- a/src/cli/browser-cli-state.option-collisions.test.ts
+++ b/src/cli/browser-cli-state.option-collisions.test.ts
@@ -8,6 +8,12 @@ const mocks = vi.hoisted(() => ({
   runtime: {
     log: vi.fn(),
     error: vi.fn(),
+    writeStdout: vi.fn((value: string) => {
+      mocks.runtime.log(value.endsWith("\n") ? value.slice(0, -1) : value);
+    }),
+    writeJson: vi.fn((value: unknown, space = 2) => {
+      mocks.runtime.log(JSON.stringify(value, null, space));
+    }),
     exit: vi.fn(),
   },
 }));
@@ -55,6 +61,8 @@ describe("browser state option collisions", () => {
     mocks.runBrowserResizeWithOutput.mockClear();
     mocks.runtime.log.mockClear();
     mocks.runtime.error.mockClear();
+    mocks.runtime.writeStdout.mockClear();
+    mocks.runtime.writeJson.mockClear();
     mocks.runtime.exit.mockClear();
   });
 
diff --git a/src/cli/config-cli.test.ts b/src/cli/config-cli.test.ts
index 954dbdc3d51..9a699856575 100644
--- a/src/cli/config-cli.test.ts
+++ b/src/cli/config-cli.test.ts
@@ -41,6 +41,7 @@ vi.mock("../runtime.js", async (importOriginal) => {
     defaultRuntime: {
       log: (...args: unknown[]) => mockLog(...args),
       error: (...args: unknown[]) => mockError(...args),
+      writeStdout: (value: string) => mockLog(value.endsWith("\n") ? value.slice(0, -1) : value),
       writeJson: (value: unknown, space = 2) =>
         mockLog(JSON.stringify(value, null, space > 0 ? space : undefined)),
       exit: (code: number) => mockExit(code),
diff --git a/src/cli/cron-cli.test.ts b/src/cli/cron-cli.test.ts
index ca4ccd0472f..4988af09a1a 100644
--- a/src/cli/cron-cli.test.ts
+++ b/src/cli/cron-cli.test.ts
@@ -29,6 +29,7 @@ vi.mock("../runtime.js", () => ({
   defaultRuntime: {
     log: vi.fn(),
     error: vi.fn(),
+    writeStdout: vi.fn(),
     writeJson: vi.fn(),
     exit: (code: number) => {
       throw new Error(`__exit__:${code}`);
diff --git a/src/cli/daemon-cli/install.integration.test.ts b/src/cli/daemon-cli/install.integration.test.ts
index db6df6a429e..52272b61f55 100644
--- a/src/cli/daemon-cli/install.integration.test.ts
+++ b/src/cli/daemon-cli/install.integration.test.ts
@@ -28,8 +28,12 @@ vi.mock("../../runtime.js", () => ({
   defaultRuntime: {
     log: (message: string) => runtimeLogs.push(message),
     error: (message: string) => runtimeErrors.push(message),
-    writeJson: (value: unknown, space = 2) =>
-      runtimeLogs.push(JSON.stringify(value, null, space > 0 ? space : undefined)),
+    writeStdout: (value: string) => {
+      runtimeLogs.push(value.endsWith("\n") ? value.slice(0, -1) : value);
+    },
+    writeJson: (value: unknown, space = 2) => {
+      runtimeLogs.push(JSON.stringify(value, null, space > 0 ? space : undefined));
+    },
     exit: (code: number) => {
       throw new Error(`__exit__:${code}`);
     },
diff --git a/src/cli/daemon-cli/install.test.ts b/src/cli/daemon-cli/install.test.ts
index 500e2bf9aaf..ddb95a8cdf6 100644
--- a/src/cli/daemon-cli/install.test.ts
+++ b/src/cli/daemon-cli/install.test.ts
@@ -129,6 +129,12 @@ const runtimeLogs: string[] = [];
 vi.mock("../../runtime.js", () => ({
   defaultRuntime: {
     log: (message: string) => runtimeLogs.push(message),
+    writeStdout: (value: string) => {
+      runtimeLogs.push(value.endsWith("\n") ? value.slice(0, -1) : value);
+    },
+    writeJson: (value: unknown, space = 2) => {
+      runtimeLogs.push(JSON.stringify(value, null, space));
+    },
     error: vi.fn(),
     exit: vi.fn(),
   },
diff --git a/src/cli/daemon-cli/test-helpers/lifecycle-core-harness.ts b/src/cli/daemon-cli/test-helpers/lifecycle-core-harness.ts
index 989f254d962..84e3611b6da 100644
--- a/src/cli/daemon-cli/test-helpers/lifecycle-core-harness.ts
+++ b/src/cli/daemon-cli/test-helpers/lifecycle-core-harness.ts
@@ -8,6 +8,8 @@ export const runtimeLogs: string[] = [];
 type LifecycleRuntimeHarness = OutputRuntimeEnv & {
   error: MockFn<OutputRuntimeEnv["error"]>;
   exit: MockFn<OutputRuntimeEnv["exit"]>;
+  writeStdout: MockFn<(value: string) => void>;
+  writeJson: MockFn<(value: unknown, space?: number) => void>;
 };
 
 type LifecycleServiceHarness = GatewayService & {
@@ -24,13 +26,13 @@ export const defaultRuntime: LifecycleRuntimeHarness = {
   log: (...args: unknown[]) => {
     runtimeLogs.push(args.map((arg) => String(arg)).join(" "));
   },
-  writeStdout: (value: string) => {
-    runtimeLogs.push(value);
-  },
-  writeJson: (value: unknown, space = 2) => {
-    runtimeLogs.push(JSON.stringify(value, null, space > 0 ? space : undefined));
-  },
   error: vi.fn(),
+  writeStdout: vi.fn((value: string) => {
+    runtimeLogs.push(value.endsWith("\n") ? value.slice(0, -1) : value);
+  }),
+  writeJson: vi.fn((value: unknown, space = 2) => {
+    runtimeLogs.push(JSON.stringify(value, null, space > 0 ? space : undefined));
+  }),
   exit: vi.fn((code: number) => {
     throw new Error(`__exit__:${code}`);
   }),
diff --git a/src/cli/devices-cli.test.ts b/src/cli/devices-cli.test.ts
index b5882c3129c..bf3627fc72e 100644
--- a/src/cli/devices-cli.test.ts
+++ b/src/cli/devices-cli.test.ts
@@ -14,7 +14,12 @@ const withProgress = vi.fn(async (_opts: unknown, fn: () => Promise<unknown>) =>
 const runtime = {
   log: vi.fn(),
   error: vi.fn(),
-  writeJson: vi.fn(),
+  writeStdout: vi.fn((value: string) => {
+    runtime.log(value.endsWith("\n") ? value.slice(0, -1) : value);
+  }),
+  writeJson: vi.fn((value: unknown, space = 2) => {
+    runtime.log(JSON.stringify(value, null, space > 0 ? space : undefined));
+  }),
   exit: vi.fn(),
 };
 
diff --git a/src/cli/directory-cli.test.ts b/src/cli/directory-cli.test.ts
index 4e11a0f648d..7247dd853b1 100644
--- a/src/cli/directory-cli.test.ts
+++ b/src/cli/directory-cli.test.ts
@@ -42,6 +42,8 @@ vi.mock("../runtime.js", () => ({
     writeJson: (value: unknown, space = 2) =>
       mocks.log(JSON.stringify(value, null, space > 0 ? space : undefined)),
     exit: (...args: unknown[]) => mocks.exit(...args),
+    writeStdout: (value: string) => mocks.log(value.endsWith("\n") ? value.slice(0, -1) : value),
+    writeJson: (value: unknown, space = 2) => mocks.log(JSON.stringify(value, null, space)),
   },
 }));
 
diff --git a/src/cli/mcp-cli.test.ts b/src/cli/mcp-cli.test.ts
index 1a1077f1c08..eb2f0fbdb73 100644
--- a/src/cli/mcp-cli.test.ts
+++ b/src/cli/mcp-cli.test.ts
@@ -15,6 +15,7 @@ vi.mock("../runtime.js", () => ({
   defaultRuntime: {
     log: (...args: unknown[]) => mockLog(...args),
     error: (...args: unknown[]) => mockError(...args),
+    writeStdout: (value: string) => mockLog(value.endsWith("\n") ? value.slice(0, -1) : value),
     writeJson: (value: unknown, space = 2) =>
       mockLog(JSON.stringify(value, null, space > 0 ? space : undefined)),
     exit: (code: number) => mockExit(code),
diff --git a/src/cli/program/register.agent.test.ts b/src/cli/program/register.agent.test.ts
index 1085c33fa21..1586bb355a9 100644
--- a/src/cli/program/register.agent.test.ts
+++ b/src/cli/program/register.agent.test.ts
@@ -15,6 +15,12 @@ const createDefaultDepsMock = vi.fn(() => ({ deps: true }));
 const runtime = {
   log: vi.fn(),
   error: vi.fn(),
+  writeStdout: vi.fn((value: string) => {
+    runtime.log(value.endsWith("\n") ? value.slice(0, -1) : value);
+  }),
+  writeJson: vi.fn((value: unknown, space = 2) => {
+    runtime.log(JSON.stringify(value, null, space));
+  }),
   exit: vi.fn(),
 };
 
diff --git a/src/cli/program/register.backup.test.ts b/src/cli/program/register.backup.test.ts
index f2d8dc95f11..c1b224b6d65 100644
--- a/src/cli/program/register.backup.test.ts
+++ b/src/cli/program/register.backup.test.ts
@@ -7,6 +7,12 @@ const backupVerifyCommand = vi.fn();
 const runtime = {
   log: vi.fn(),
   error: vi.fn(),
+  writeStdout: vi.fn((value: string) => {
+    runtime.log(value.endsWith("\n") ? value.slice(0, -1) : value);
+  }),
+  writeJson: vi.fn((value: unknown, space = 2) => {
+    runtime.log(JSON.stringify(value, null, space));
+  }),
   exit: vi.fn(),
 };
 
diff --git a/src/cli/program/register.status-health-sessions.test.ts b/src/cli/program/register.status-health-sessions.test.ts
index 5a45b4d293a..86cbe1869ee 100644
--- a/src/cli/program/register.status-health-sessions.test.ts
+++ b/src/cli/program/register.status-health-sessions.test.ts
@@ -10,6 +10,12 @@ const setVerbose = vi.fn();
 const runtime = {
   log: vi.fn(),
   error: vi.fn(),
+  writeStdout: vi.fn((value: string) => {
+    runtime.log(value.endsWith("\n") ? value.slice(0, -1) : value);
+  }),
+  writeJson: vi.fn((value: unknown, space = 2) => {
+    runtime.log(JSON.stringify(value, null, space));
+  }),
   exit: vi.fn(),
 };
 
diff --git a/src/cli/qr-cli.test.ts b/src/cli/qr-cli.test.ts
index 8d984c857ff..c7d54a6247a 100644
--- a/src/cli/qr-cli.test.ts
+++ b/src/cli/qr-cli.test.ts
@@ -6,6 +6,9 @@ const mocks = vi.hoisted(() => ({
   runtime: {
     log: vi.fn(),
     error: vi.fn(),
+    writeStdout: vi.fn((value: string) => {
+      mocks.runtime.log(value.endsWith("\n") ? value.slice(0, -1) : value);
+    }),
     writeJson: vi.fn((value: unknown, space = 2) => {
       mocks.runtime.log(JSON.stringify(value, null, space > 0 ? space : undefined));
     }),
diff --git a/src/cli/route.test.ts b/src/cli/route.test.ts
index 9e7c6c7c110..a335f4f56e9 100644
--- a/src/cli/route.test.ts
+++ b/src/cli/route.test.ts
@@ -23,7 +23,13 @@ vi.mock("./program/routes.js", () => ({
 }));
 
 vi.mock("../runtime.js", () => ({
-  defaultRuntime: { error: vi.fn(), log: vi.fn(), exit: vi.fn() },
+  defaultRuntime: {
+    error: vi.fn(),
+    log: vi.fn(),
+    writeStdout: vi.fn(),
+    writeJson: vi.fn(),
+    exit: vi.fn(),
+  },
 }));
 
 describe("tryRouteCli", () => {
diff --git a/src/cli/test-runtime-capture.ts b/src/cli/test-runtime-capture.ts
index ddd9a0db047..6ff5df0b0de 100644
--- a/src/cli/test-runtime-capture.ts
+++ b/src/cli/test-runtime-capture.ts
@@ -22,7 +22,7 @@ export function createCliRuntimeCapture(): CliRuntimeCapture {
         runtimeErrors.push(stringifyArgs(args));
       },
       writeStdout: (value: string) => {
-        runtimeLogs.push(value);
+        runtimeLogs.push(value.endsWith("\n") ? value.slice(0, -1) : value);
       },
       writeJson: (value: unknown, space = 2) => {
         runtimeLogs.push(JSON.stringify(value, null, space > 0 ? space : undefined));
diff --git a/src/cli/update-cli.option-collisions.test.ts b/src/cli/update-cli.option-collisions.test.ts
index 6db4cfdd260..e38b38184aa 100644
--- a/src/cli/update-cli.option-collisions.test.ts
+++ b/src/cli/update-cli.option-collisions.test.ts
@@ -9,6 +9,12 @@ const updateWizardCommand = vi.fn(async (_opts: unknown) => {});
 const defaultRuntime = {
   log: vi.fn(),
   error: vi.fn(),
+  writeStdout: vi.fn((value: string) => {
+    defaultRuntime.log(value.endsWith("\n") ? value.slice(0, -1) : value);
+  }),
+  writeJson: vi.fn((value: unknown, space = 2) => {
+    defaultRuntime.log(JSON.stringify(value, null, space));
+  }),
   exit: vi.fn(),
 };
 
@@ -41,6 +47,8 @@ describe("update cli option collisions", () => {
     updateWizardCommand.mockClear();
     defaultRuntime.log.mockClear();
     defaultRuntime.error.mockClear();
+    defaultRuntime.writeStdout.mockClear();
+    defaultRuntime.writeJson.mockClear();
     defaultRuntime.exit.mockClear();
   });
 
diff --git a/src/cli/update-cli.test.ts b/src/cli/update-cli.test.ts
index 4781137fad5..b38e2c4075f 100644
--- a/src/cli/update-cli.test.ts
+++ b/src/cli/update-cli.test.ts
@@ -139,6 +139,9 @@ vi.mock("../runtime.js", () => ({
   defaultRuntime: {
     log: runtimeLog,
     error: runtimeError,
+    writeStdout: vi.fn((value: string) =>
+      runtimeLog(value.endsWith("\n") ? value.slice(0, -1) : value),
+    ),
     writeJson: runtimeWriteJson,
     exit: runtimeExit,
   },