diff --git a/packages/cli/src/commands/mcp/add.ts b/packages/cli/src/commands/mcp/add.ts
index 73894294f4..205608407f 100644
--- a/packages/cli/src/commands/mcp/add.ts
+++ b/packages/cli/src/commands/mcp/add.ts
@@ -192,7 +192,7 @@ async function addMcpServer(
         );
       }
       await client.close();
-    } catch (e) {
+    } catch {
       debugLogger.warn(
         'Warning: With sandboxing enabled, any read-only tools provided by this server will AUTO-EXECUTE without confirmation.',
       );
diff --git a/packages/core/src/tools/mcp-client.ts b/packages/core/src/tools/mcp-client.ts
index b0a33a2c4e..b9a4ce8b8b 100644
--- a/packages/core/src/tools/mcp-client.ts
+++ b/packages/core/src/tools/mcp-client.ts
@@ -2303,7 +2303,13 @@ export async function createTransport(
       preparedProgram = prepared.program;
       preparedArgs = prepared.args;
       preparedCwd = prepared.cwd || preparedCwd;
-      preparedEnv = prepared.env as Record<string, string>;
+      const env: Record<string, string> = {};
+      for (const [key, value] of Object.entries(prepared.env)) {
+        if (value !== undefined) {
+          env[key] = value;
+        }
+      }
+      preparedEnv = env;
     }
 
     let transport: Transport = new StdioClientTransport({