fix(mcp): don't capture external Claude/Codex config errors as wizard exceptions

src/steps/add-mcp-server-to-clients/__tests__/plugin-client.test.ts

@@ -0,0 +1,27 @@
+import { isExternalClientConfigError } from '../plugin-client';
+
+describe('isExternalClientConfigError', () => {
+  it('matches Claude Code malformed plugin schema errors', () => {
+    expect(
+      isExternalClientConfigError(
+        'Invalid schema: plugins.5.source: Invalid input',
+      ),
+    ).toBe(true);
+    expect(
+      isExternalClientConfigError(
+        'Command failed: claude plugin install posthog\n' +
+          'Invalid schema: plugins.0.source: Invalid input',
+      ),
+    ).toBe(true);
+  });
+
+  it('does not match unrelated CLI errors', () => {
+    expect(isExternalClientConfigError('network timeout')).toBe(false);
+    expect(isExternalClientConfigError('command not found')).toBe(false);
+    expect(isExternalClientConfigError('ENOENT')).toBe(false);
+  });
+
+  it('handles empty input safely', () => {
+    expect(isExternalClientConfigError('')).toBe(false);
+  });
+});

src/steps/add-mcp-server-to-clients/clients/__tests__/claude-code.test.ts

@@ -129,6 +129,21 @@ describe('ClaudeCodeMCPClient — plugin methods', () => {
       );
     });
 
+    it('returns failure without capturing exception when ~/.claude config is malformed', async () => {
+      execSyncMock.mockImplementation((cmd: string) => {
+        if (String(cmd).includes('plugin install')) {
+          throw new Error(
+            'Command failed: claude plugin install posthog\n' +
+              'Invalid schema: plugins.5.source: Invalid input',
+          );
+        }
+        return Buffer.from('');
+      });
+      const client = new ClaudeCodeMCPClient();
+      await expect(client.installPlugin()).resolves.toEqual({ success: false });
+      expect(analytics.captureException).not.toHaveBeenCalled();
+    });
+
     it('returns failure when no binary is found', async () => {
       execSyncMock.mockImplementation(() => {
         throw new Error('not found');
@@ -137,4 +152,39 @@ describe('ClaudeCodeMCPClient — plugin methods', () => {
       await expect(client.installPlugin()).resolves.toEqual({ success: false });
     });
   });
+
+  describe('removeServer', () => {
+    it('returns success when claude mcp remove exits 0', async () => {
+      execSyncMock.mockImplementation(() => Buffer.from(''));
+      const client = new ClaudeCodeMCPClient();
+      await expect(client.removeServer()).resolves.toEqual({ success: true });
+    });
+
+    it('returns failure and captures exception on unexpected error', async () => {
+      execSyncMock.mockImplementation((cmd: string) => {
+        if (cmd === 'command -v claude') return Buffer.from('');
+        throw new Error('network timeout');
+      });
+      const client = new ClaudeCodeMCPClient();
+      await expect(client.removeServer()).resolves.toEqual({ success: false });
+      expect(analytics.captureException).toHaveBeenCalledWith(
+        expect.objectContaining({
+          message: expect.stringContaining('network timeout'),
+        }),
+      );
+    });
+
+    it('returns failure without capturing exception when ~/.claude config is malformed', async () => {
+      execSyncMock.mockImplementation((cmd: string) => {
+        if (cmd === 'command -v claude') return Buffer.from('');
+        throw new Error(
+          'Command failed: claude mcp remove --scope user posthog\n' +
+            'Invalid schema: plugins.0.source: Invalid input',
+        );
+      });
+      const client = new ClaudeCodeMCPClient();
+      await expect(client.removeServer()).resolves.toEqual({ success: false });
+      expect(analytics.captureException).not.toHaveBeenCalled();
+    });
+  });
 });

src/steps/add-mcp-server-to-clients/clients/__tests__/codex.test.ts

@@ -102,22 +102,32 @@ describe('CodexMCPClient', () => {
 
   describe('removeServer', () => {
     it('invokes the resolved binary with mcp remove and returns success', async () => {
-      spawnSyncMock.mockReturnValue({ status: 0 });
+      spawnSyncMock.mockReturnValue({ status: 0, stderr: '' });
       const client = new CodexMCPClient();
       await expect(client.removeServer()).resolves.toEqual({ success: true });
       expect(spawnSyncMock).toHaveBeenCalledWith(
         CODEX_PATH,
         ['mcp', 'remove', 'posthog'],
-        { stdio: 'ignore' },
+        { encoding: 'utf-8' },
       );
     });
 
     it('returns false and captures exception on failure', async () => {
-      spawnSyncMock.mockReturnValue({ status: 1 });
+      spawnSyncMock.mockReturnValue({ status: 1, stderr: 'network timeout' });
       const client = new CodexMCPClient();
       await expect(client.removeServer()).resolves.toEqual({ success: false });
       expect(analytics.captureException).toHaveBeenCalled();
     });
+
+    it('returns failure without capturing exception when Codex config is malformed', async () => {
+      spawnSyncMock.mockReturnValue({
+        status: 1,
+        stderr: 'Invalid schema: plugins.2.source: Invalid input',
+      });
+      const client = new CodexMCPClient();
+      await expect(client.removeServer()).resolves.toEqual({ success: false });
+      expect(analytics.captureException).not.toHaveBeenCalled();
+    });
   });
 
   describe('supportsPlugin', () => {
@@ -175,5 +185,15 @@ describe('CodexMCPClient', () => {
         }),
       );
     });
+
+    it('returns failure without capturing exception when Codex config is malformed', async () => {
+      spawnSyncMock.mockReturnValue({
+        status: 1,
+        stderr: 'Invalid schema: plugins.5.source: Invalid input',
+      });
+      const client = new CodexMCPClient();
+      await expect(client.installPlugin()).resolves.toEqual({ success: false });
+      expect(analytics.captureException).not.toHaveBeenCalled();
+    });
   });
 });

src/steps/add-mcp-server-to-clients/clients/claude-code.ts

@@ -1,6 +1,10 @@
 import { DefaultMCPClient } from '../MCPClient';
 import { DefaultMCPClientConfig } from '../defaults';
-import { PluginCapable, PluginInstallResult } from '../plugin-client';
+import {
+  PluginCapable,
+  PluginInstallResult,
+  isExternalClientConfigError,
+} from '../plugin-client';
 import { z } from 'zod';
 import { execSync } from 'child_process';
 import { analytics } from '../../../utils/analytics';
@@ -110,12 +114,16 @@ export class ClaudeCodeMCPClient
     try {
       execSync(command);
     } catch (error) {
+      const msg = error instanceof Error ? error.message : String(error);
+      if (isExternalClientConfigError(msg)) {
+        debug(
+          `  Claude Code mcp remove skipped: existing ~/.claude config has invalid plugin entries. ` +
+            `Fix them with 'claude plugin list' and retry.`,
+        );
+        return Promise.resolve({ success: false });
+      }
       analytics.captureException(
-        new Error(
-          `Failed to remove server from Claude Code: ${
-            error instanceof Error ? error.message : String(error)
-          }`,
-        ),
+        new Error(`Failed to remove server from Claude Code: ${msg}`),
       );
       return Promise.resolve({ success: false });
     }
@@ -151,6 +159,13 @@ export class ClaudeCodeMCPClient
       if (msg.includes('already installed') || msg.includes('already exists')) {
         return Promise.resolve({ success: true, alreadyInstalled: true });
       }
+      if (isExternalClientConfigError(msg)) {
+        debug(
+          `  Claude Code plugin install skipped: existing ~/.claude config has invalid plugin entries. ` +
+            `Fix them with 'claude plugin list' and retry.`,
+        );
+        return Promise.resolve({ success: false });
+      }
       analytics.captureException(
         new Error(`Claude Code plugin install failed: ${msg}`),
       );

src/steps/add-mcp-server-to-clients/clients/codex.ts

@@ -6,9 +6,14 @@ import * as path from 'node:path';
 
 import { DefaultMCPClient } from '../MCPClient';
 import { DefaultMCPClientConfig } from '../defaults';
-import { PluginCapable, PluginInstallResult } from '../plugin-client';
+import {
+  PluginCapable,
+  PluginInstallResult,
+  isExternalClientConfigError,
+} from '../plugin-client';
 
 import { analytics } from '../../../utils/analytics';
+import { debug } from '../../../utils/debug';
 
 export const CodexMCPConfig = DefaultMCPClientConfig;
 
@@ -60,12 +65,19 @@ export class CodexMCPClient extends DefaultMCPClient implements PluginCapable {
     if (!binary) return Promise.resolve({ success: false });
 
     const result = spawnSync(binary, ['mcp', 'remove', 'posthog'], {
-      stdio: 'ignore',
+      encoding: 'utf-8',
     });
 
     if (result.error || result.status !== 0) {
+      const stderr = result.stderr ?? '';
+      if (isExternalClientConfigError(stderr)) {
+        debug(
+          `Codex mcp remove skipped: existing Codex config is malformed. ${stderr.trim()}`,
+        );
+        return Promise.resolve({ success: false });
+      }
       analytics.captureException(
-        new Error('Failed to remove server from Codex CLI.'),
+        new Error(`Failed to remove server from Codex CLI: ${stderr}`),
       );
       return Promise.resolve({ success: false });
     }
@@ -122,8 +134,15 @@ export class CodexMCPClient extends DefaultMCPClient implements PluginCapable {
     }
 
     if (result.status !== 0) {
+      const stderr = result.stderr ?? '';
+      if (isExternalClientConfigError(stderr)) {
+        debug(
+          `Codex plugin install skipped: existing Codex config is malformed. ${stderr.trim()}`,
+        );
+        return Promise.resolve({ success: false });
+      }
       analytics.captureException(
-        new Error(`Codex plugin install failed: ${result.stderr ?? ''}`),
+        new Error(`Codex plugin install failed: ${stderr}`),
       );
       return Promise.resolve({ success: false });
     }

src/steps/add-mcp-server-to-clients/plugin-client.ts

@@ -17,3 +17,18 @@ export function isPluginCapable<T>(client: T): client is T & PluginCapable {
     'installPlugin' in client
   );
 }
+
+// Errors emitted by an MCP host CLI (Claude Code, Codex, …) when its own
+// pre-existing user config is malformed — i.e. the wizard's command was
+// rejected before it could run, because of state outside the wizard's scope.
+// We must not capture these as wizard exceptions.
+const EXTERNAL_CLIENT_CONFIG_ERROR_PATTERNS: RegExp[] = [
+  // Claude Code: malformed plugin entries in ~/.claude config, e.g.
+  // "Invalid schema: plugins.5.source: Invalid input"
+  /Invalid schema:[^\n]*plugins\.\d+\./i,
+];
+
+export function isExternalClientConfigError(message: string): boolean {
+  if (!message) return false;
+  return EXTERNAL_CLIENT_CONFIG_ERROR_PATTERNS.some((p) => p.test(message));
+}