diff --git a/apps/frontend/src/main/__tests__/cli-tool-manager.test.ts b/apps/frontend/src/main/__tests__/cli-tool-manager.test.ts
index 5222690779..9eef26079a 100644
--- a/apps/frontend/src/main/__tests__/cli-tool-manager.test.ts
+++ b/apps/frontend/src/main/__tests__/cli-tool-manager.test.ts
@@ -105,6 +105,23 @@ vi.mock('../env-utils', () => ({
     }
     return /\.(cmd|bat)$/i.test(command);
   }),
+  getSpawnCommand: vi.fn((command: string) => {
+    // Mock getSpawnCommand to match actual behavior
+    const trimmed = command.trim();
+    // On Windows, quote .cmd/.bat files
+    if (process.platform === 'win32' && /\.(cmd|bat)$/i.test(trimmed)) {
+      // Idempotent - if already quoted, return as-is
+      if (trimmed.startsWith('"') && trimmed.endsWith('"')) {
+        return trimmed;
+      }
+      return `"${trimmed}"`;
+    }
+    // For non-.cmd/.bat files, return trimmed (strip quotes if present)
+    if (trimmed.startsWith('"') && trimmed.endsWith('"')) {
+      return trimmed.slice(1, -1);
+    }
+    return trimmed;
+  }),
   getSpawnOptions: vi.fn((command: string, baseOptions?: any) => ({
     ...baseOptions,
     shell: /\.(cmd|bat)$/i.test(command) && process.platform === 'win32'
diff --git a/apps/frontend/src/main/__tests__/env-utils.test.ts b/apps/frontend/src/main/__tests__/env-utils.test.ts
index cc0ee17c72..994a334d20 100644
--- a/apps/frontend/src/main/__tests__/env-utils.test.ts
+++ b/apps/frontend/src/main/__tests__/env-utils.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it, beforeEach, afterEach } from 'vitest';
-import { shouldUseShell, getSpawnOptions } from '../env-utils';
+import { shouldUseShell, getSpawnOptions, getSpawnCommand } from '../env-utils';
 
 describe('shouldUseShell', () => {
   const originalPlatform = process.platform;
@@ -198,3 +198,181 @@ describe('getSpawnOptions', () => {
     });
   });
 });
+
+describe('getSpawnCommand', () => {
+  const originalPlatform = process.platform;
+
+  afterEach(() => {
+    // Restore original platform after each test
+    Object.defineProperty(process, 'platform', {
+      value: originalPlatform,
+      writable: true,
+      configurable: true,
+    });
+  });
+
+  describe('Windows platform', () => {
+    beforeEach(() => {
+      Object.defineProperty(process, 'platform', {
+        value: 'win32',
+        writable: true,
+        configurable: true,
+      });
+    });
+
+    it('should quote .cmd files with spaces', () => {
+      const cmd = getSpawnCommand('C:\\Users\\First Last\\AppData\\Roaming\\npm\\claude.cmd');
+      expect(cmd).toBe('"C:\\Users\\First Last\\AppData\\Roaming\\npm\\claude.cmd"');
+    });
+
+    it('should quote .cmd files without spaces too (idempotent)', () => {
+      const cmd = getSpawnCommand('C:\\Users\\admin\\AppData\\Roaming\\npm\\claude.cmd');
+      expect(cmd).toBe('"C:\\Users\\admin\\AppData\\Roaming\\npm\\claude.cmd"');
+    });
+
+    it('should quote .bat files with spaces', () => {
+      const cmd = getSpawnCommand('D:\\Program Files (x86)\\scripts\\setup.bat');
+      expect(cmd).toBe('"D:\\Program Files (x86)\\scripts\\setup.bat"');
+    });
+
+    it('should NOT quote .exe files', () => {
+      const cmd = getSpawnCommand('C:\\Program Files\\Git\\cmd\\git.exe');
+      expect(cmd).toBe('C:\\Program Files\\Git\\cmd\\git.exe');
+    });
+
+    it('should NOT quote extensionless files', () => {
+      const cmd = getSpawnCommand('D:\\Git\\bin\\bash');
+      expect(cmd).toBe('D:\\Git\\bin\\bash');
+    });
+
+    it('should handle uppercase .CMD and .BAT extensions', () => {
+      expect(getSpawnCommand('D:\\Tools\\CLAUDE.CMD')).toBe('"D:\\Tools\\CLAUDE.CMD"');
+      expect(getSpawnCommand('C:\\Scripts\\SETUP.BAT')).toBe('"C:\\Scripts\\SETUP.BAT"');
+    });
+
+    it('should be idempotent - already quoted .cmd files stay quoted', () => {
+      const cmd = getSpawnCommand('"C:\\Users\\admin\\AppData\\Roaming\\npm\\claude.cmd"');
+      expect(cmd).toBe('"C:\\Users\\admin\\AppData\\Roaming\\npm\\claude.cmd"');
+    });
+
+    it('should be idempotent - already quoted .bat files stay quoted', () => {
+      const cmd = getSpawnCommand('"D:\\Program Files\\scripts\\setup.bat"');
+      expect(cmd).toBe('"D:\\Program Files\\scripts\\setup.bat"');
+    });
+
+    it('should be idempotent - double-quoting does not occur', () => {
+      const once = getSpawnCommand('C:\\Users\\admin\\npm\\claude.cmd');
+      const twice = getSpawnCommand(once);
+      expect(once).toBe(twice);
+      expect(once).toBe('"C:\\Users\\admin\\npm\\claude.cmd"');
+    });
+
+    it('should trim whitespace before processing', () => {
+      const cmd = getSpawnCommand('  C:\\Users\\admin\\npm\\claude.cmd  ');
+      expect(cmd).toBe('"C:\\Users\\admin\\npm\\claude.cmd"');
+    });
+
+    it('should handle already-quoted .cmd with spaces', () => {
+      const cmd = getSpawnCommand('"C:\\Users\\First Last\\npm\\claude.cmd"');
+      expect(cmd).toBe('"C:\\Users\\First Last\\npm\\claude.cmd"');
+    });
+
+    it('should strip quotes from .exe files (defensive: no quotes with shell:false)', () => {
+      const cmd = getSpawnCommand('"C:\\Program Files\\Git\\cmd\\git.exe"');
+      expect(cmd).toBe('C:\\Program Files\\Git\\cmd\\git.exe');
+    });
+
+    it('should strip quotes from extensionless files (defensive: no quotes with shell:false)', () => {
+      const cmd = getSpawnCommand('"D:\\Git\\bin\\bash"');
+      expect(cmd).toBe('D:\\Git\\bin\\bash');
+    });
+
+    it('should strip quotes and trim whitespace from .exe files', () => {
+      const cmd = getSpawnCommand('  "C:\\Program Files\\Git\\cmd\\git.exe"  ');
+      expect(cmd).toBe('C:\\Program Files\\Git\\cmd\\git.exe');
+    });
+  });
+
+  describe('Non-Windows platforms', () => {
+    it('should NOT quote commands on macOS', () => {
+      Object.defineProperty(process, 'platform', {
+        value: 'darwin',
+        writable: true,
+        configurable: true,
+      });
+      expect(getSpawnCommand('/usr/local/bin/claude')).toBe('/usr/local/bin/claude');
+      expect(getSpawnCommand('/opt/homebrew/bin/claude.cmd')).toBe('/opt/homebrew/bin/claude.cmd');
+    });
+
+    it('should NOT quote commands on Linux', () => {
+      Object.defineProperty(process, 'platform', {
+        value: 'linux',
+        writable: true,
+        configurable: true,
+      });
+      expect(getSpawnCommand('/usr/bin/claude')).toBe('/usr/bin/claude');
+      expect(getSpawnCommand('/home/user/.local/bin/claude.bat')).toBe('/home/user/.local/bin/claude.bat');
+    });
+
+    it('should trim whitespace on macOS', () => {
+      Object.defineProperty(process, 'platform', {
+        value: 'darwin',
+        writable: true,
+        configurable: true,
+      });
+      expect(getSpawnCommand('  /usr/local/bin/claude  ')).toBe('/usr/local/bin/claude');
+      expect(getSpawnCommand('\t/opt/homebrew/bin/claude\t')).toBe('/opt/homebrew/bin/claude');
+    });
+
+    it('should trim whitespace on Linux', () => {
+      Object.defineProperty(process, 'platform', {
+        value: 'linux',
+        writable: true,
+        configurable: true,
+      });
+      expect(getSpawnCommand('  /usr/bin/claude  ')).toBe('/usr/bin/claude');
+      expect(getSpawnCommand('\t/home/user/.local/bin/claude\t')).toBe('/home/user/.local/bin/claude');
+    });
+  });
+});
+
+describe('shouldUseShell with quoted paths', () => {
+  const originalPlatform = process.platform;
+
+  afterEach(() => {
+    // Restore original platform after each test
+    Object.defineProperty(process, 'platform', {
+      value: originalPlatform,
+      writable: true,
+      configurable: true,
+    });
+  });
+
+  describe('Windows platform', () => {
+    beforeEach(() => {
+      Object.defineProperty(process, 'platform', {
+        value: 'win32',
+        writable: true,
+        configurable: true,
+      });
+    });
+
+    it('should detect .cmd files in quoted paths', () => {
+      expect(shouldUseShell('"C:\\Users\\admin\\npm\\claude.cmd"')).toBe(true);
+      expect(shouldUseShell('"D:\\Tools\\CLAUDE.CMD"')).toBe(true);
+    });
+
+    it('should detect .bat files in quoted paths', () => {
+      expect(shouldUseShell('"C:\\Scripts\\setup.bat"')).toBe(true);
+      expect(shouldUseShell('"D:\\Program Files\\script.BAT"')).toBe(true);
+    });
+
+    it('should NOT detect .exe files in quoted paths', () => {
+      expect(shouldUseShell('"C:\\Program Files\\git.exe"')).toBe(false);
+    });
+
+    it('should handle whitespace around quoted paths', () => {
+      expect(shouldUseShell('  "C:\\Users\\admin\\npm\\claude.cmd"  ')).toBe(true);
+    });
+  });
+});
diff --git a/apps/frontend/src/main/cli-tool-manager.ts b/apps/frontend/src/main/cli-tool-manager.ts
index 3aa514d1e6..cf7013f98e 100644
--- a/apps/frontend/src/main/cli-tool-manager.ts
+++ b/apps/frontend/src/main/cli-tool-manager.ts
@@ -26,7 +26,7 @@ import path from 'path';
 import os from 'os';
 import { promisify } from 'util';
 import { app } from 'electron';
-import { findExecutable, findExecutableAsync, getAugmentedEnv, getAugmentedEnvAsync, shouldUseShell, existsAsync } from './env-utils';
+import { findExecutable, findExecutableAsync, getAugmentedEnv, getAugmentedEnvAsync, shouldUseShell, existsAsync, getSpawnCommand } from './env-utils';
 import type { ToolDetectionResult } from '../shared/types';
 
 const execFileAsync = promisify(execFile);
@@ -923,7 +923,7 @@ class CLIToolManager {
       if (needsShell) {
         // For .cmd/.bat files on Windows, use execSync with quoted path
         // execFileSync doesn't handle spaces in .cmd paths correctly even with shell:true
-        const quotedCmd = `"${claudeCmd}"`;
+        const quotedCmd = getSpawnCommand(claudeCmd);
         version = execSync(`${quotedCmd} --version`, {
           encoding: 'utf-8',
           timeout: 5000,
@@ -1039,7 +1039,7 @@ class CLIToolManager {
 
       if (needsShell) {
         // For .cmd/.bat files on Windows, use exec with quoted path
-        const quotedCmd = `"${claudeCmd}"`;
+        const quotedCmd = getSpawnCommand(claudeCmd);
         const result = await execAsync(`${quotedCmd} --version`, {
           encoding: 'utf-8',
           timeout: 5000,
diff --git a/apps/frontend/src/main/env-utils.ts b/apps/frontend/src/main/env-utils.ts
index 8463a2ace4..8d4b88478c 100644
--- a/apps/frontend/src/main/env-utils.ts
+++ b/apps/frontend/src/main/env-utils.ts
@@ -463,8 +463,12 @@ export function shouldUseShell(command: string): boolean {
     return false;
   }
 
+  const trimmed = command.trim();
+  const unquoted =
+    trimmed.startsWith('"') && trimmed.endsWith('"') ? trimmed.slice(1, -1) : trimmed;
+
   // Check if command ends with .cmd or .bat (case-insensitive)
-  return /\.(cmd|bat)$/i.test(command);
+  return /\.(cmd|bat)$/i.test(unquoted);
 }
 
 /**
@@ -473,6 +477,9 @@ export function shouldUseShell(command: string): boolean {
  * Provides a consistent way to create spawn options that work across platforms.
  * Handles the shell requirement for Windows .cmd/.bat files automatically.
  *
+ * For .cmd/.bat files on Windows, returns options that tell the caller to use
+ * proper quoting for paths with spaces.
+ *
  * @param command - The command path to execute
  * @param baseOptions - Base spawn options to merge with (optional)
  * @returns Spawn options with correct shell setting
@@ -480,7 +487,7 @@ export function shouldUseShell(command: string): boolean {
  * @example
  * ```typescript
  * const opts = getSpawnOptions(claudeCmd, { cwd: '/project', env: {...} });
- * spawn(claudeCmd, ['--version'], opts);
+ * spawn(getSpawnCommand(claudeCmd), ['--version'], opts);
  * ```
  */
 export function getSpawnOptions(
@@ -505,3 +512,37 @@ export function getSpawnOptions(
     shell: shouldUseShell(command),
   };
 }
+
+/**
+ * Get the properly quoted command for use with spawn()
+ *
+ * For .cmd/.bat files on Windows with shell:true, the command path must be
+ * quoted to handle paths containing spaces correctly (e.g., C:\Users\OXFAM MONS\...).
+ *
+ * @param command - The command path to execute
+ * @returns The command (quoted if needed for .cmd/.bat files on Windows)
+ *
+ * @example
+ * ```typescript
+ * const cmd = getSpawnCommand(claudeCmd); // "C:\Users\OXFAM MONS\...\claude.cmd"
+ * const opts = getSpawnOptions(claudeCmd, { cwd: '/project', env: {...} });
+ * spawn(cmd, ['--version'], opts);
+ * ```
+ */
+export function getSpawnCommand(command: string): string {
+  // For .cmd/.bat files on Windows, quote the command to handle spaces
+  // The shell will parse the quoted path correctly
+  const trimmed = command.trim();
+  if (shouldUseShell(trimmed)) {
+    // Idempotent if already quoted
+    if (trimmed.startsWith('"') && trimmed.endsWith('"')) {
+      return trimmed;
+    }
+    return `"${trimmed}"`;
+  }
+  // For non-.cmd/.bat files, strip quotes if present (defensive: no double quotes with shell:false)
+  if (trimmed.startsWith('"') && trimmed.endsWith('"')) {
+    return trimmed.slice(1, -1);
+  }
+  return trimmed;
+}
diff --git a/apps/frontend/src/main/ipc-handlers/env-handlers.ts b/apps/frontend/src/main/ipc-handlers/env-handlers.ts
index 3a9cbe417f..c0d7e2278e 100644
--- a/apps/frontend/src/main/ipc-handlers/env-handlers.ts
+++ b/apps/frontend/src/main/ipc-handlers/env-handlers.ts
@@ -10,7 +10,7 @@ import { projectStore } from '../project-store';
 import { parseEnvFile } from './utils';
 import { getClaudeCliInvocation, getClaudeCliInvocationAsync } from '../claude-cli-utils';
 import { debugError } from '../../shared/utils/debug-logger';
-import { getSpawnOptions } from '../env-utils';
+import { getSpawnOptions, getSpawnCommand } from '../env-utils';
 
 // GitLab environment variable keys
 const GITLAB_ENV_KEYS = {
@@ -603,7 +603,7 @@ ${existingVars['GRAPHITI_DB_PATH'] ? `GRAPHITI_DB_PATH=${existingVars['GRAPHITI_
       try {
         // Check if Claude CLI is available and authenticated
         const result = await new Promise<ClaudeAuthResult>((resolve) => {
-          const proc = spawn(claudeCmd, ['--version'], getSpawnOptions(claudeCmd, {
+          const proc = spawn(getSpawnCommand(claudeCmd), ['--version'], getSpawnOptions(claudeCmd, {
             cwd: project.path,
             env: claudeEnv,
           }));
@@ -623,7 +623,7 @@ ${existingVars['GRAPHITI_DB_PATH'] ? `GRAPHITI_DB_PATH=${existingVars['GRAPHITI_
             if (code === 0) {
               // Claude CLI is available, check if authenticated
               // Run a simple command that requires auth
-              const authCheck = spawn(claudeCmd, ['api', '--help'], getSpawnOptions(claudeCmd, {
+              const authCheck = spawn(getSpawnCommand(claudeCmd), ['api', '--help'], getSpawnOptions(claudeCmd, {
                 cwd: project.path,
                 env: claudeEnv,
               }));
@@ -692,7 +692,7 @@ ${existingVars['GRAPHITI_DB_PATH'] ? `GRAPHITI_DB_PATH=${existingVars['GRAPHITI_
       try {
         // Run claude setup-token which will open browser for OAuth
         const result = await new Promise<ClaudeAuthResult>((resolve) => {
-          const proc = spawn(claudeCmd, ['setup-token'], getSpawnOptions(claudeCmd, {
+          const proc = spawn(getSpawnCommand(claudeCmd), ['setup-token'], getSpawnOptions(claudeCmd, {
             cwd: project.path,
             env: claudeEnv,
             stdio: 'inherit' // This allows the terminal to handle the interactive auth