diff --git a/packages/vscode/src/opencode.ts b/packages/vscode/src/opencode.ts
index 540a9aba..c7e5cd85 100644
--- a/packages/vscode/src/opencode.ts
+++ b/packages/vscode/src/opencode.ts
@@ -196,10 +196,30 @@ function isMacOpenCodeAppBundlePath(candidate: string): boolean {
   return process.platform === 'darwin' && /\/OpenCode\.app\/Contents\/MacOS\/(?:OpenCode|opencode-cli)$/i.test(candidate);
 }
 
+function isWindowsOpenCodeDesktopAppPath(candidate: string): boolean {
+  if (process.platform !== 'win32' || typeof candidate !== 'string') {
+    return false;
+  }
+  const localAppData = typeof process.env.LOCALAPPDATA === 'string' && process.env.LOCALAPPDATA.trim()
+    ? path.resolve(process.env.LOCALAPPDATA).toLowerCase()
+    : '';
+  if (!localAppData) {
+    return false;
+  }
+  const normalized = path.resolve(candidate).toLowerCase();
+  return normalized.startsWith(`${localAppData}${path.sep}`)
+    && normalized.endsWith(`${path.sep}programs${path.sep}opencode${path.sep}opencode.exe`);
+}
+
+function isKnownOpenCodeDesktopAppPath(candidate: string): boolean {
+  return isMacOpenCodeAppBundlePath(candidate) || isWindowsOpenCodeDesktopAppPath(candidate);
+}
+
 function createConfiguredOpencodeBinaryError(raw: string, normalized: string): Error {
   const messageSuffix = 'OpenChamber needs the standalone opencode CLI. Install it and set openchamber.opencodeBinary to the CLI path, for example ~/.opencode/bin/opencode, or leave the setting empty to use PATH lookup.';
-  if (isMacOpenCodeAppBundlePath(raw) || isMacOpenCodeAppBundlePath(normalized)) {
-    return new Error(`Configured OpenCode binary points at the macOS desktop app bundle, not the CLI: ${normalized}. ${messageSuffix}`);
+  if (isKnownOpenCodeDesktopAppPath(raw) || isKnownOpenCodeDesktopAppPath(normalized)) {
+    const platformName = process.platform === 'win32' ? 'Windows desktop app install' : 'macOS desktop app bundle';
+    return new Error(`Configured OpenCode binary points at the ${platformName}, not the CLI: ${normalized}. ${messageSuffix}`);
   }
 
   try {
@@ -254,7 +274,7 @@ function validateConfiguredOpencodeBinaryForManagedStart(): string | null {
     return null;
   }
 
-  if (isExecutable(normalized) && !isMacOpenCodeAppBundlePath(normalized)) {
+  if (isExecutable(normalized) && !isKnownOpenCodeDesktopAppPath(normalized)) {
     return normalized;
   }
 
@@ -271,7 +291,7 @@ function resolveOpencodeCliPath(): string | null {
     }
   })();
 
-  if (configured && isExecutable(configured) && !isMacOpenCodeAppBundlePath(configured)) {
+  if (configured && isExecutable(configured) && !isKnownOpenCodeDesktopAppPath(configured)) {
     return configured;
   }
 
@@ -288,7 +308,7 @@ function resolveOpencodeCliPath(): string | null {
     }
   })();
 
-  if (sharedFromOpenChamber && isExecutable(sharedFromOpenChamber) && !isMacOpenCodeAppBundlePath(sharedFromOpenChamber)) {
+  if (sharedFromOpenChamber && isExecutable(sharedFromOpenChamber) && !isKnownOpenCodeDesktopAppPath(sharedFromOpenChamber)) {
     return sharedFromOpenChamber;
   }
 
@@ -302,13 +322,13 @@ function resolveOpencodeCliPath(): string | null {
     .filter(Boolean);
 
   for (const candidate of explicit) {
-    if (isExecutable(candidate)) {
+    if (isExecutable(candidate) && !isKnownOpenCodeDesktopAppPath(candidate)) {
       return candidate;
     }
   }
 
   if (cachedDetectedOpencodeCliPath) {
-    if (isExecutable(cachedDetectedOpencodeCliPath)) {
+    if (isExecutable(cachedDetectedOpencodeCliPath) && !isKnownOpenCodeDesktopAppPath(cachedDetectedOpencodeCliPath)) {
       return cachedDetectedOpencodeCliPath;
     }
     cachedDetectedOpencodeCliPath = undefined;
@@ -327,7 +347,6 @@ function resolveOpencodeCliPath(): string | null {
   const winFallbacks = (() => {
     const userProfile = process.env.USERPROFILE || home;
     const appData = process.env.APPDATA || path.join(userProfile, 'AppData', 'Roaming');
-    const localAppData = process.env.LOCALAPPDATA || '';
     const programData = process.env.ProgramData || 'C:\\ProgramData';
     const npmDir = path.join(appData, 'npm');
 
@@ -344,14 +363,12 @@ function resolveOpencodeCliPath(): string | null {
       // Bun global install
       path.join(userProfile, '.bun', 'bin', 'opencode.exe'),
       path.join(userProfile, '.bun', 'bin', 'opencode.cmd'),
-      // Some installers use LocalAppData
-      localAppData ? path.join(localAppData, 'Programs', 'opencode', 'opencode.exe') : '',
     ].filter(Boolean);
   })();
 
   if (process.platform !== 'win32') {
     const fromPath = findExecutableInPath('opencode');
-    if (fromPath) {
+    if (fromPath && !isKnownOpenCodeDesktopAppPath(fromPath)) {
       cachedDetectedOpencodeCliPath = fromPath;
       return fromPath;
     }
@@ -359,7 +376,7 @@ function resolveOpencodeCliPath(): string | null {
 
   const fallbacks = process.platform === 'win32' ? winFallbacks : unixFallbacks;
   for (const candidate of fallbacks) {
-    if (isExecutable(candidate)) {
+    if (isExecutable(candidate) && !isKnownOpenCodeDesktopAppPath(candidate)) {
       cachedDetectedOpencodeCliPath = candidate;
       return candidate;
     }
@@ -367,7 +384,7 @@ function resolveOpencodeCliPath(): string | null {
 
   if (process.platform === 'win32') {
     const fromPath = findExecutableInPath('opencode');
-    if (fromPath) {
+    if (fromPath && !isKnownOpenCodeDesktopAppPath(fromPath)) {
       cachedDetectedOpencodeCliPath = fromPath;
       return fromPath;
     }
@@ -382,7 +399,7 @@ function resolveOpencodeCliPath(): string | null {
           .split(/\r?\n/)
           .map((line) => line.trim())
           .filter(Boolean);
-        const found = lines.find((line) => isExecutable(line));
+        const found = lines.find((line) => isExecutable(line) && !isKnownOpenCodeDesktopAppPath(line));
         if (found) {
           cachedDetectedOpencodeCliPath = found;
           return found;
diff --git a/packages/web/server/lib/opencode/env-runtime.js b/packages/web/server/lib/opencode/env-runtime.js
index 998128d3..bee62da1 100644
--- a/packages/web/server/lib/opencode/env-runtime.js
+++ b/packages/web/server/lib/opencode/env-runtime.js
@@ -260,6 +260,20 @@ export const createOpenCodeEnvRuntime = (deps) => {
     return /(^|[\\/])wsl(\.exe)?$/i.test(trimmed);
   };
 
+  const isWindowsOpenCodeDesktopAppPath = (candidate) => {
+    if (process.platform !== 'win32' || typeof candidate !== 'string') {
+      return false;
+    }
+    const normalized = path.resolve(candidate).toLowerCase();
+    const localAppData = typeof process.env.LOCALAPPDATA === 'string' && process.env.LOCALAPPDATA.trim()
+      ? path.resolve(process.env.LOCALAPPDATA).toLowerCase()
+      : '';
+    if (!localAppData || !normalized.startsWith(`${localAppData}${path.sep}`)) {
+      return false;
+    }
+    return normalized.endsWith(`${path.sep}programs${path.sep}opencode${path.sep}opencode.exe`);
+  };
+
   const clearWslOpencodeResolution = () => {
     state.useWslForOpencode = false;
     state.resolvedWslBinary = null;
@@ -278,7 +292,7 @@ export const createOpenCodeEnvRuntime = (deps) => {
       .filter(Boolean);
 
     for (const candidate of explicit) {
-      if (isExecutable(candidate)) {
+      if (isExecutable(candidate) && !isWindowsOpenCodeDesktopAppPath(candidate)) {
         clearWslOpencodeResolution();
         state.resolvedOpencodeBinarySource = 'env';
         return candidate;
@@ -319,7 +333,6 @@ export const createOpenCodeEnvRuntime = (deps) => {
         path.join(programData, 'chocolatey', 'bin', 'opencode.cmd'),
         path.join(userProfile, '.bun', 'bin', 'opencode.exe'),
         path.join(userProfile, '.bun', 'bin', 'opencode.cmd'),
-        localAppData ? path.join(localAppData, 'Programs', 'opencode', 'opencode.exe') : '',
       ].filter(Boolean);
     })();
 
@@ -344,7 +357,7 @@ export const createOpenCodeEnvRuntime = (deps) => {
             .split(/\r?\n/)
             .map((line) => line.trim())
             .filter(Boolean);
-          const found = lines.find((line) => isExecutable(line));
+          const found = lines.find((line) => isExecutable(line) && !isWindowsOpenCodeDesktopAppPath(line));
           if (found) {
             clearWslOpencodeResolution();
             state.resolvedOpencodeBinarySource = 'where';
@@ -824,13 +837,17 @@ export const createOpenCodeEnvRuntime = (deps) => {
     return /\/OpenCode\.app\/Contents\/MacOS\/(?:OpenCode|opencode-cli)$/i.test(candidate);
   };
 
+  const isKnownOpenCodeDesktopAppPath = (candidate) => isMacOpenCodeAppBundlePath(candidate)
+    || isWindowsOpenCodeDesktopAppPath(candidate);
+
   const createConfiguredOpencodeBinaryError = (raw, normalized) => {
     const configured = typeof raw === 'string' ? raw.trim() : '';
     const candidate = typeof normalized === 'string' && normalized.trim().length > 0 ? normalized.trim() : configured;
     const messageSuffix = 'OpenChamber needs the standalone opencode CLI. Install it and set settings.opencodeBinary to the CLI path, for example ~/.opencode/bin/opencode, or leave the setting empty to use PATH lookup.';
     const error = (() => {
-      if (isMacOpenCodeAppBundlePath(candidate) || isMacOpenCodeAppBundlePath(configured)) {
-        return new Error(`Configured OpenCode binary points at the macOS desktop app bundle, not the CLI: ${candidate}. ${messageSuffix}`);
+      if (isKnownOpenCodeDesktopAppPath(candidate) || isKnownOpenCodeDesktopAppPath(configured)) {
+        const platformName = process.platform === 'win32' ? 'Windows desktop app install' : 'macOS desktop app bundle';
+        return new Error(`Configured OpenCode binary points at the ${platformName}, not the CLI: ${candidate}. ${messageSuffix}`);
       }
 
       try {
@@ -927,7 +944,7 @@ export const createOpenCodeEnvRuntime = (deps) => {
         return null;
       }
 
-      if (normalized && isExecutable(normalized) && !isMacOpenCodeAppBundlePath(normalized)) {
+      if (normalized && isExecutable(normalized) && !isKnownOpenCodeDesktopAppPath(normalized)) {
         clearWslOpencodeResolution();
         process.env.OPENCODE_BINARY = normalized;
         prependToPath(path.dirname(normalized));
diff --git a/packages/web/server/lib/opencode/env-runtime.test.js b/packages/web/server/lib/opencode/env-runtime.test.js
index c0ad1e7f..0e432a11 100644
--- a/packages/web/server/lib/opencode/env-runtime.test.js
+++ b/packages/web/server/lib/opencode/env-runtime.test.js
@@ -7,6 +7,7 @@ import { createOpenCodeEnvRuntime } from './env-runtime.js';
 const originalOpencodeBinary = process.env.OPENCODE_BINARY;
 const originalComSpec = process.env.ComSpec;
 const originalPath = process.env.PATH;
+const originalLocalAppData = process.env.LOCALAPPDATA;
 const originalSystemRoot = process.env.SystemRoot;
 const originalWslBinary = process.env.WSL_BINARY;
 const originalOpenChamberWslBinary = process.env.OPENCHAMBER_WSL_BINARY;
@@ -59,6 +60,12 @@ afterEach(() => {
     delete process.env.SystemRoot;
   }
 
+  if (typeof originalLocalAppData === 'string') {
+    process.env.LOCALAPPDATA = originalLocalAppData;
+  } else {
+    delete process.env.LOCALAPPDATA;
+  }
+
   if (typeof originalWslBinary === 'string') {
     process.env.WSL_BINARY = originalWslBinary;
   } else {
@@ -138,6 +145,58 @@ describe('OpenCode env runtime', () => {
     });
   });
 
+  it('rejects known Windows OpenCode desktop app install paths', async () => {
+    setPlatform('win32');
+    const localAppData = createTempDir('openchamber-localappdata-');
+    const desktopBinary = path.join(localAppData, 'Programs', 'OpenCode', 'OpenCode.exe');
+    fs.mkdirSync(path.dirname(desktopBinary), { recursive: true });
+    fs.writeFileSync(desktopBinary, '');
+    process.env.LOCALAPPDATA = localAppData;
+    const { runtime } = createRuntime({ opencodeBinary: desktopBinary });
+
+    await expect(runtime.applyOpencodeBinaryFromSettings({ strict: true })).rejects.toMatchObject({
+      code: 'OPENCODE_BINARY_INVALID',
+      message: expect.stringContaining('Windows desktop app install'),
+    });
+  });
+
+  it('does not auto-detect the Windows OpenCode desktop app as a CLI', () => {
+    setPlatform('win32');
+    const localAppData = createTempDir('openchamber-localappdata-');
+    const desktopBinary = path.join(localAppData, 'Programs', 'OpenCode', 'OpenCode.exe');
+    fs.mkdirSync(path.dirname(desktopBinary), { recursive: true });
+    fs.writeFileSync(desktopBinary, '');
+    process.env.LOCALAPPDATA = localAppData;
+    process.env.PATH = createTempDir('openchamber-empty-path-');
+    process.env.SystemRoot = createTempDir('openchamber-empty-systemroot-');
+    delete process.env.OPENCODE_BINARY;
+    const { runtime } = createRuntime({}, {
+      spawnSync: () => ({ status: 1, stdout: '', stderr: '' }),
+    });
+
+    expect(runtime.resolveOpencodeCliPath()).toBeNull();
+  });
+
+  it('skips Windows OpenCode desktop app entries returned by where.exe', () => {
+    setPlatform('win32');
+    const localAppData = createTempDir('openchamber-localappdata-');
+    const desktopBinary = path.join(localAppData, 'Programs', 'OpenCode', 'OpenCode.exe');
+    const cliBinary = path.join(createTempDir('openchamber-cli-'), 'opencode.exe');
+    fs.mkdirSync(path.dirname(desktopBinary), { recursive: true });
+    fs.writeFileSync(desktopBinary, '');
+    fs.writeFileSync(cliBinary, '');
+    process.env.LOCALAPPDATA = localAppData;
+    process.env.PATH = createTempDir('openchamber-empty-path-');
+    process.env.SystemRoot = createTempDir('openchamber-empty-systemroot-');
+    delete process.env.OPENCODE_BINARY;
+    const { runtime, state } = createRuntime({}, {
+      spawnSync: () => ({ status: 0, stdout: `${desktopBinary}\r\n${cliBinary}\r\n`, stderr: '' }),
+    });
+
+    expect(runtime.resolveOpencodeCliPath()).toBe(cliBinary);
+    expect(state.resolvedOpencodeBinarySource).toBe('where');
+  });
+
   it('rejects WSL settings in strict mode', async () => {
     setPlatform('win32');
     const dir = createTempDir('openchamber-no-wsl-');