diff --git a/apps/backend/core/auth.py b/apps/backend/core/auth.py
index 51fa9df3..fc85a289 100644
--- a/apps/backend/core/auth.py
+++ b/apps/backend/core/auth.py
@@ -58,6 +58,8 @@ SDK_ENV_VARS = [
     "API_TIMEOUT_MS",
     # Windows-specific: Git Bash path for Claude Code CLI
     "CLAUDE_CODE_GIT_BASH_PATH",
+    # Claude CLI path override (allows frontend to pass detected CLI path to SDK)
+    "CLAUDE_CLI_PATH",
 ]
 
 
diff --git a/apps/frontend/scripts/download-python.cjs b/apps/frontend/scripts/download-python.cjs
index c2e00c84..724bf246 100644
--- a/apps/frontend/scripts/download-python.cjs
+++ b/apps/frontend/scripts/download-python.cjs
@@ -105,7 +105,10 @@ const STRIP_PATTERNS = {
   // Format: 'package_name/subpath' - removes the entire subpath
   packagePaths: [
     'googleapiclient/discovery_cache/documents',  // Cached Google API discovery docs (92MB!)
-    'claude_agent_sdk/_bundled',                  // Bundled Claude CLI (224MB!) - users have it installed separately
+    // NOTE: claude_agent_sdk/_bundled is NO LONGER excluded.
+    // On Windows, the system-installed Claude CLI is claude.cmd (a batch script),
+    // which cannot be executed by anyio.open_process() / asyncio.create_subprocess_exec().
+    // The SDK's bundled claude.exe is a proper executable and works correctly.
   ],
   // Packages that should NEVER be bundled (too large, specialized)
   // If these appear in dependencies, warn and skip
diff --git a/apps/frontend/src/main/agent/agent-process.test.ts b/apps/frontend/src/main/agent/agent-process.test.ts
index de10c034..ea6ce5b5 100644
--- a/apps/frontend/src/main/agent/agent-process.test.ts
+++ b/apps/frontend/src/main/agent/agent-process.test.ts
@@ -123,6 +123,8 @@ vi.mock('../cli-tool-manager', () => ({
     }
     return { found: false, path: undefined, source: 'user-config', message: `${tool} not found` };
   }),
+  // getClaudeCliPathForSdk returns null by default (simulates not found or .cmd file on Windows)
+  getClaudeCliPathForSdk: vi.fn(() => null),
   deriveGitBashPath: vi.fn(() => null),
   clearCache: vi.fn()
 }));
@@ -159,7 +161,7 @@ import { AgentEvents } from './agent-events';
 import * as profileService from '../services/profile';
 import * as rateLimitDetector from '../rate-limit-detector';
 import { pythonEnvManager } from '../python-env-manager';
-import { getToolInfo } from '../cli-tool-manager';
+import { getToolInfo, getClaudeCliPathForSdk } from '../cli-tool-manager';
 
 describe('AgentProcessManager - API Profile Env Injection (Story 2.3)', () => {
   let processManager: AgentProcessManager;
@@ -754,11 +756,11 @@ describe('AgentProcessManager - API Profile Env Injection (Story 2.3)', () => {
     });
 
     it('should set GITHUB_CLI_PATH with same precedence as CLAUDE_CLI_PATH', async () => {
-      // Mock both Claude CLI and gh CLI as found
+      // Mock Claude CLI via getClaudeCliPathForSdk (returns path directly, not .cmd file)
+      vi.mocked(getClaudeCliPathForSdk).mockReturnValue('/opt/homebrew/bin/claude');
+
+      // Mock gh CLI via getToolInfo (gh still uses standard detection)
       vi.mocked(getToolInfo).mockImplementation((tool: string) => {
-        if (tool === 'claude') {
-          return { found: true, path: '/opt/homebrew/bin/claude', source: 'homebrew', message: 'Claude CLI found via Homebrew' };
-        }
         if (tool === 'gh') {
           return { found: true, path: '/opt/homebrew/bin/gh', source: 'homebrew', message: 'gh CLI found via Homebrew' };
         }
diff --git a/apps/frontend/src/main/agent/agent-process.ts b/apps/frontend/src/main/agent/agent-process.ts
index 26e7337d..76f0a4b4 100644
--- a/apps/frontend/src/main/agent/agent-process.ts
+++ b/apps/frontend/src/main/agent/agent-process.ts
@@ -23,7 +23,7 @@ import { readSettingsFile } from '../settings-utils';
 import type { AppSettings } from '../../shared/types/settings';
 import { getOAuthModeClearVars } from './env-utils';
 import { getAugmentedEnv } from '../env-utils';
-import { getToolInfo } from '../cli-tool-manager';
+import { getToolInfo, getClaudeCliPathForSdk } from '../cli-tool-manager';
 import { killProcessGracefully } from '../platform';
 
 /**
@@ -134,6 +134,9 @@ export class AgentProcessManager {
    * Common issue: CLI tools installed via Homebrew or other non-standard locations
    * are not in subprocess PATH when app launches from Finder/Dock.
    *
+   * For 'claude' tool specifically, uses getClaudeCliPathForSdk() which returns null
+   * for Windows .cmd files, allowing the SDK to use its bundled claude.exe instead.
+   *
    * @param toolName - Name of the CLI tool (e.g., 'claude', 'gh')
    * @returns Record with env var set if tool was detected
    */
@@ -142,10 +145,23 @@ export class AgentProcessManager {
     const envVarName = CLI_TOOL_ENV_MAP[toolName];
     if (!process.env[envVarName]) {
       try {
-        const toolInfo = getToolInfo(toolName);
-        if (toolInfo.found && toolInfo.path) {
-          env[envVarName] = toolInfo.path;
-          console.log(`[AgentProcess] Setting ${envVarName}:`, toolInfo.path, `(source: ${toolInfo.source})`);
+        // For 'claude' tool, use getClaudeCliPathForSdk() which returns null for Windows .cmd files
+        // This allows the Claude Agent SDK to use its bundled claude.exe instead
+        if (toolName === 'claude') {
+          const cliPath = getClaudeCliPathForSdk();
+          if (cliPath) {
+            env[envVarName] = cliPath;
+            console.log(`[AgentProcess] Setting ${envVarName}:`, cliPath, '(source: cli-tool-manager)');
+          } else {
+            console.log(`[AgentProcess] Claude CLI is .cmd file on Windows, not setting ${envVarName} - SDK will use bundled CLI`);
+          }
+        } else {
+          // For other tools, use standard detection
+          const toolInfo = getToolInfo(toolName);
+          if (toolInfo.found && toolInfo.path) {
+            env[envVarName] = toolInfo.path;
+            console.log(`[AgentProcess] Setting ${envVarName}:`, toolInfo.path, `(source: ${toolInfo.source})`);
+          }
         }
       } catch (error) {
         console.warn(`[AgentProcess] Failed to detect ${toolName} CLI path:`, error instanceof Error ? error.message : String(error));
diff --git a/apps/frontend/src/main/changelog/formatter.ts b/apps/frontend/src/main/changelog/formatter.ts
index a43be3af..3272fa52 100644
--- a/apps/frontend/src/main/changelog/formatter.ts
+++ b/apps/frontend/src/main/changelog/formatter.ts
@@ -318,6 +318,9 @@ CRITICAL: Output ONLY the raw changelog content. Do NOT include ANY introductory
 
 /**
  * Create Python script for Claude generation
+ *
+ * On Windows, .cmd/.bat files require shell=True in subprocess.run() because
+ * they are batch scripts that need cmd.exe to execute, not direct executables.
  */
 export function createGenerationScript(prompt: string, claudePath: string): string {
   // Convert prompt to base64 to avoid any string escaping issues in Python
@@ -326,6 +329,10 @@ export function createGenerationScript(prompt: string, claudePath: string): stri
   // Escape the claude path for Python string
   const escapedClaudePath = claudePath.replace(/\\/g, '\\\\').replace(/'/g, "\\'");
 
+  // Detect if this is a Windows batch file (.cmd or .bat)
+  // These require shell=True in subprocess.run() because they need cmd.exe to execute
+  const isCmdFile = /\.(cmd|bat)$/i.test(claudePath);
+
   return `
 import subprocess
 import sys
@@ -337,12 +344,14 @@ try:
 
     # Use Claude Code CLI to generate
     # stdin=DEVNULL prevents hanging when claude checks for interactive input
+    # shell=${isCmdFile ? 'True' : 'False'} - Windows .cmd files require shell execution
     result = subprocess.run(
         ['${escapedClaudePath}', '-p', prompt, '--output-format', 'text', '--model', 'haiku'],
         capture_output=True,
         text=True,
         stdin=subprocess.DEVNULL,
-        timeout=300
+        timeout=300,
+        shell=${isCmdFile ? 'True' : 'False'}
     )
 
     if result.returncode == 0:
diff --git a/apps/frontend/src/main/changelog/version-suggester.ts b/apps/frontend/src/main/changelog/version-suggester.ts
index 6d4a9b91..e195f9c7 100644
--- a/apps/frontend/src/main/changelog/version-suggester.ts
+++ b/apps/frontend/src/main/changelog/version-suggester.ts
@@ -126,6 +126,9 @@ Respond with ONLY a JSON object in this exact format (no markdown, no extra text
 
   /**
    * Create Python script to run Claude analysis
+   *
+   * On Windows, .cmd/.bat files require shell=True in subprocess.run() because
+   * they are batch scripts that need cmd.exe to execute, not direct executables.
    */
   private createAnalysisScript(prompt: string): string {
     // Escape the prompt for Python string literal
@@ -134,6 +137,15 @@ Respond with ONLY a JSON object in this exact format (no markdown, no extra text
       .replace(/"/g, '\\"')
       .replace(/\n/g, '\\n');
 
+    // Escape the claude path for Python string (handle Windows backslashes)
+    const escapedClaudePath = this.claudePath
+      .replace(/\\/g, '\\\\')
+      .replace(/"/g, '\\"');
+
+    // Detect if this is a Windows batch file (.cmd or .bat)
+    // These require shell=True in subprocess.run() because they need cmd.exe to execute
+    const isCmdFile = /\.(cmd|bat)$/i.test(this.claudePath);
+
     return `
 import subprocess
 import sys
@@ -142,11 +154,13 @@ import sys
 prompt = "${escapedPrompt}"
 
 try:
+    # shell=${isCmdFile ? 'True' : 'False'} - Windows .cmd files require shell execution
     result = subprocess.run(
-        ["${this.claudePath}", "chat", "--model", "haiku", "--prompt", prompt],
+        ["${escapedClaudePath}", "chat", "--model", "haiku", "--prompt", prompt],
         capture_output=True,
         text=True,
-        check=True
+        check=True,
+        shell=${isCmdFile ? 'True' : 'False'}
     )
     print(result.stdout)
 except subprocess.CalledProcessError as e:
diff --git a/apps/frontend/src/main/cli-tool-manager.ts b/apps/frontend/src/main/cli-tool-manager.ts
index fb5c1d0c..d1bb0f85 100644
--- a/apps/frontend/src/main/cli-tool-manager.ts
+++ b/apps/frontend/src/main/cli-tool-manager.ts
@@ -330,6 +330,30 @@ class CLIToolManager {
     return tool;
   }
 
+  /**
+   * Get Claude CLI path for SDK usage
+   *
+   * Returns null when a .cmd file is detected on Windows, so the SDK
+   * can use its bundled claude.exe instead. The SDK's bundled CLI is
+   * a proper Windows executable that can be spawned by anyio.open_process().
+   *
+   * @returns Claude CLI path, or null if SDK should use bundled CLI
+   */
+  getClaudeCliPathForSdk(): string | null {
+    const claudePath = this.getToolPath('claude');
+
+    // On Windows, .cmd files cannot be executed by anyio.open_process() / asyncio.create_subprocess_exec().
+    // Return null so the Claude Agent SDK uses its bundled claude.exe instead.
+    if (isWindows() && claudePath.toLowerCase().endsWith('.cmd')) {
+      console.warn(
+        `[CLI Tools] Claude CLI is .cmd file, returning null so SDK uses bundled CLI: ${claudePath}`
+      );
+      return null;
+    }
+
+    return claudePath;
+  }
+
   /**
    * Detect the path for a specific CLI tool
    *
@@ -1032,6 +1056,29 @@ class CLIToolManager {
     return tool;
   }
 
+  /**
+   * Get Claude CLI path for SDK usage asynchronously (non-blocking)
+   *
+   * Returns null when a .cmd file is detected on Windows, so the SDK
+   * can use its bundled claude.exe instead.
+   *
+   * @returns Promise resolving to Claude CLI path, or null if SDK should use bundled CLI
+   */
+  async getClaudeCliPathForSdkAsync(): Promise<string | null> {
+    const claudePath = await this.getToolPathAsync('claude');
+
+    // On Windows, .cmd files cannot be executed by anyio.open_process() / asyncio.create_subprocess_exec().
+    // Return null so the Claude Agent SDK uses its bundled claude.exe instead.
+    if (isWindows() && claudePath.toLowerCase().endsWith('.cmd')) {
+      console.warn(
+        `[CLI Tools] Claude CLI is .cmd file, returning null so SDK uses bundled CLI: ${claudePath}`
+      );
+      return null;
+    }
+
+    return claudePath;
+  }
+
   /**
    * Detect tool path asynchronously
    *
@@ -1763,6 +1810,31 @@ export function getToolPath(tool: CLITool): string {
   return cliToolManager.getToolPath(tool);
 }
 
+/**
+ * Get Claude CLI path for SDK usage
+ *
+ * Returns null when a .cmd file is detected on Windows, so the SDK
+ * can use its bundled claude.exe instead. The SDK's bundled CLI is
+ * a proper Windows executable that can be spawned by anyio.open_process().
+ *
+ * Use this function when passing a CLI path to the Claude Agent SDK.
+ * For other uses (like spawning claude directly), use getToolPath('claude').
+ *
+ * @returns Claude CLI path, or null if SDK should use bundled CLI
+ *
+ * @example
+ * ```typescript
+ * import { getClaudeCliPathForSdk } from './cli-tool-manager';
+ *
+ * const cliPath = getClaudeCliPathForSdk();
+ * // Pass to Python backend which uses Claude Agent SDK
+ * // If null, SDK will use its bundled claude.exe
+ * ```
+ */
+export function getClaudeCliPathForSdk(): string | null {
+  return cliToolManager.getClaudeCliPathForSdk();
+}
+
 /**
  * Configure CLI tools with user settings
  *
@@ -1873,6 +1945,26 @@ export async function getToolPathAsync(tool: CLITool): Promise<string> {
   return cliToolManager.getToolPathAsync(tool);
 }
 
+/**
+ * Get Claude CLI path for SDK usage asynchronously (non-blocking)
+ *
+ * Returns null when a .cmd file is detected on Windows, so the SDK
+ * can use its bundled claude.exe instead.
+ *
+ * @returns Promise resolving to Claude CLI path, or null if SDK should use bundled CLI
+ *
+ * @example
+ * ```typescript
+ * import { getClaudeCliPathForSdkAsync } from './cli-tool-manager';
+ *
+ * const cliPath = await getClaudeCliPathForSdkAsync();
+ * // Pass to Python backend which uses Claude Agent SDK
+ * ```
+ */
+export async function getClaudeCliPathForSdkAsync(): Promise<string | null> {
+  return cliToolManager.getClaudeCliPathForSdkAsync();
+}
+
 /**
  * Pre-warm the CLI tool cache asynchronously
  *
diff --git a/apps/frontend/src/main/python-detector.ts b/apps/frontend/src/main/python-detector.ts
index 1d993a65..eb74e5d4 100644
--- a/apps/frontend/src/main/python-detector.ts
+++ b/apps/frontend/src/main/python-detector.ts
@@ -291,6 +291,12 @@ const ALLOWED_PATH_PATTERNS: RegExp[] = [
   /^.*\/miniconda\d*\/bin\/python\d*(\.\d+)?$/,
   /^.*\/anaconda\d*\/envs\/[^/]+\/bin\/python\d*(\.\d+)?$/,
   /^.*\/miniconda\d*\/envs\/[^/]+\/bin\/python\d*(\.\d+)?$/,
+  // Bundled Python in packaged Electron apps (macOS/Linux)
+  // Matches paths like: /path/to/app/resources/python/bin/python3
+  /^.*\/resources\/python\/bin\/python\d*(\.\d+)?$/,
+  // Bundled Python in packaged Electron apps (Windows)
+  // Matches paths like: C:\path\to\app\resources\python\python.exe
+  /^.*\\resources\\python\\python\.exe$/i,
 ];
 
 /**