From cac24863a04779529893b4e1713bf1144fe95bea Mon Sep 17 00:00:00 2001
From: karashiiro <49822414+karashiiro@users.noreply.github.com>
Date: Sun, 4 Jan 2026 16:15:34 -0800
Subject: [PATCH] Allow writing to stdout from IPC adapter

---
 .../adapter/src/__tests__/ipc.test.ts         | 18 ++++++++------
 .../adapter/src/__tests__/sdk-adapter.test.ts | 24 +++++++++++--------
 backend/packages/adapter/src/ipc.ts           |  5 +++-
 3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/backend/packages/adapter/src/__tests__/ipc.test.ts b/backend/packages/adapter/src/__tests__/ipc.test.ts
index 6f7d2f9..1ba1e29 100644
--- a/backend/packages/adapter/src/__tests__/ipc.test.ts
+++ b/backend/packages/adapter/src/__tests__/ipc.test.ts
@@ -1,20 +1,24 @@
 import { describe, expect, it, mock, spyOn, beforeEach, afterEach } from 'bun:test';
 
-// Mock console.log to capture emit output
+// Mock process.stdout.write to capture emit output
 describe('IPC Layer', () => {
-  let originalLog: typeof console.log;
+  let originalWrite: typeof process.stdout.write;
   let logOutput: string[] = [];
 
   beforeEach(() => {
-    originalLog = console.log;
+    originalWrite = process.stdout.write.bind(process.stdout);
     logOutput = [];
-    console.log = (...args: unknown[]) => {
-      logOutput.push(args.map(String).join(' '));
-    };
+    process.stdout.write = ((chunk: string | Uint8Array) => {
+      if (typeof chunk === 'string') {
+        // Remove trailing newline for easier testing
+        logOutput.push(chunk.replace(/\n$/, ''));
+      }
+      return true;
+    }) as typeof process.stdout.write;
   });
 
   afterEach(() => {
-    console.log = originalLog;
+    process.stdout.write = originalWrite;
   });
 
   describe('emit', () => {
diff --git a/backend/packages/adapter/src/__tests__/sdk-adapter.test.ts b/backend/packages/adapter/src/__tests__/sdk-adapter.test.ts
index 66c9e95..d4209e8 100644
--- a/backend/packages/adapter/src/__tests__/sdk-adapter.test.ts
+++ b/backend/packages/adapter/src/__tests__/sdk-adapter.test.ts
@@ -1,24 +1,28 @@
 import { describe, expect, it, beforeEach, afterEach, mock } from 'bun:test';
 import { PROTOCOL_VERSION, ErrorCodes } from '@tiny-workshop/ipc-types';
 
-// Capture emitted messages
+// Capture emitted messages via process.stdout.write
 let emittedMessages: unknown[] = [];
-let originalLog: typeof console.log;
+let originalWrite: typeof process.stdout.write;
 
 beforeEach(() => {
   emittedMessages = [];
-  originalLog = console.log;
-  console.log = (...args: unknown[]) => {
-    try {
-      emittedMessages.push(JSON.parse(args[0] as string));
-    } catch {
-      // Not JSON, ignore
+  originalWrite = process.stdout.write.bind(process.stdout);
+  process.stdout.write = ((chunk: string | Uint8Array) => {
+    if (typeof chunk === 'string') {
+      try {
+        // Remove trailing newline and parse JSON
+        emittedMessages.push(JSON.parse(chunk.replace(/\n$/, '')));
+      } catch {
+        // Not JSON, ignore
+      }
     }
-  };
+    return true;
+  }) as typeof process.stdout.write;
 });
 
 afterEach(() => {
-  console.log = originalLog;
+  process.stdout.write = originalWrite;
 });
 
 describe('SdkAdapter', () => {
diff --git a/backend/packages/adapter/src/ipc.ts b/backend/packages/adapter/src/ipc.ts
index 66fc66a..2c101e1 100644
--- a/backend/packages/adapter/src/ipc.ts
+++ b/backend/packages/adapter/src/ipc.ts
@@ -7,9 +7,12 @@ import type { FrontendMessage, BackendMessage } from '@tiny-workshop/ipc-types';
 
 /**
  * Emit a message to the frontend via stdout
+ *
+ * Uses process.stdout.write directly to bypass stdout protection.
+ * This is the ONLY place that should write to stdout!
  */
 export function emit(msg: BackendMessage): void {
-  console.log(JSON.stringify(msg));
+  process.stdout.write(JSON.stringify(msg) + '\n');
 }
 
 /**
-- 
2.51.2