From a2fe3d2ad055fadc6e3dcc032286a3e3ba2a0a8c Mon Sep 17 00:00:00 2001
From: Tommaso Sciortino <sciortino@gmail.com>
Date: Fri, 13 Jun 2025 14:51:29 -0700
Subject: [PATCH] Stop extension MCPs from hopping into settings. (#1026)

---
 packages/cli/src/config/config.test.ts    | 29 +++++++++++++++++++++++
 packages/cli/src/config/config.ts         |  2 +-
 packages/cli/src/config/extension.test.ts |  4 ++--
 packages/cli/src/config/extension.ts      |  2 +-
 4 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/packages/cli/src/config/config.test.ts b/packages/cli/src/config/config.test.ts
index 60c693bb..313deedf 100644
--- a/packages/cli/src/config/config.test.ts
+++ b/packages/cli/src/config/config.test.ts
@@ -269,3 +269,32 @@ describe('Hierarchical Memory Loading (config.ts) - Placeholder Suite', () => {
   });
   */
 });
+
+describe('mergeMcpServers', () => {
+  it('should not modify the original settings object', async () => {
+    const settings: Settings = {
+      mcpServers: {
+        'test-server': {
+          url: 'http://localhost:8080',
+        },
+      },
+    };
+    const extensions: Extension[] = [
+      {
+        config: {
+          name: 'ext1',
+          version: '1.0.0',
+          mcpServers: {
+            'ext1-server': {
+              url: 'http://localhost:8081',
+            },
+          },
+        },
+        contextFiles: [],
+      },
+    ];
+    const originalSettings = JSON.parse(JSON.stringify(settings));
+    await loadCliConfig(settings, extensions, [], 'test-session');
+    expect(settings).toEqual(originalSettings);
+  });
+});
diff --git a/packages/cli/src/config/config.ts b/packages/cli/src/config/config.ts
index b9a995ed..9534f403 100644
--- a/packages/cli/src/config/config.ts
+++ b/packages/cli/src/config/config.ts
@@ -205,7 +205,7 @@ export async function loadCliConfig(
 }
 
 function mergeMcpServers(settings: Settings, extensions: Extension[]) {
-  const mcpServers = settings.mcpServers || {};
+  const mcpServers = { ...(settings.mcpServers || {}) };
   for (const extension of extensions) {
     Object.entries(extension.config.mcpServers || {}).forEach(
       ([key, server]) => {
diff --git a/packages/cli/src/config/extension.test.ts b/packages/cli/src/config/extension.test.ts
index 754e9dd0..7d299c78 100644
--- a/packages/cli/src/config/extension.test.ts
+++ b/packages/cli/src/config/extension.test.ts
@@ -72,7 +72,7 @@ describe('loadExtensions', () => {
       'ext1',
       '1.0.0',
       false,
-      'my-context.md',
+      'my-context-file.md',
     );
 
     const extensions = loadExtensions(tempWorkspaceDir);
@@ -80,7 +80,7 @@ describe('loadExtensions', () => {
     expect(extensions).toHaveLength(1);
     const ext1 = extensions.find((e) => e.config.name === 'ext1');
     expect(ext1?.contextFiles).toEqual([
-      path.join(workspaceExtensionsDir, 'ext1', 'my-context.md'),
+      path.join(workspaceExtensionsDir, 'ext1', 'my-context-file.md'),
     ]);
   });
 });
diff --git a/packages/cli/src/config/extension.ts b/packages/cli/src/config/extension.ts
index 84863e32..418e5fb9 100644
--- a/packages/cli/src/config/extension.ts
+++ b/packages/cli/src/config/extension.ts
@@ -107,7 +107,7 @@ function loadExtension(extensionDir: string): Extension | null {
 
 function getContextFileNames(config: ExtensionConfig): string[] {
   if (!config.contextFileName) {
-    return ['GEMINI.md', 'gemini.md', 'Gemini.md'];
+    return ['GEMINI.md'];
   } else if (!Array.isArray(config.contextFileName)) {
     return [config.contextFileName];
   }