diff --git a/src/utils/terminalShellEnvironment.test.ts b/src/utils/terminalShellEnvironment.test.ts
index c7b52b61..fdf39e27 100644
--- a/src/utils/terminalShellEnvironment.test.ts
+++ b/src/utils/terminalShellEnvironment.test.ts
@@ -101,4 +101,42 @@ describe('terminal shell environment', () => {
 
     expect(env).toBeNull()
   })
+
+  it('does not capture shell env when the current process owns an interactive TTY', async () => {
+    const stdinDescriptor = Object.getOwnPropertyDescriptor(process.stdin, 'isTTY')
+    const stdoutDescriptor = Object.getOwnPropertyDescriptor(process.stdout, 'isTTY')
+
+    Object.defineProperty(process.stdin, 'isTTY', {
+      configurable: true,
+      value: true,
+    })
+    Object.defineProperty(process.stdout, 'isTTY', {
+      configurable: true,
+      value: true,
+    })
+
+    try {
+      const shellPath = path.join(tmpDir, 'zsh')
+      await writeFakeZsh(shellPath)
+
+      const env = await getTerminalShellEnvironment({
+        HOME: tmpDir,
+        SHELL: shellPath,
+        PATH: '/usr/bin:/bin',
+      })
+
+      expect(env).toBeNull()
+    } finally {
+      if (stdinDescriptor) {
+        Object.defineProperty(process.stdin, 'isTTY', stdinDescriptor)
+      } else {
+        delete (process.stdin as { isTTY?: boolean }).isTTY
+      }
+      if (stdoutDescriptor) {
+        Object.defineProperty(process.stdout, 'isTTY', stdoutDescriptor)
+      } else {
+        delete (process.stdout as { isTTY?: boolean }).isTTY
+      }
+    }
+  })
 })
diff --git a/src/utils/terminalShellEnvironment.ts b/src/utils/terminalShellEnvironment.ts
index f13367a8..8ee4b629 100644
--- a/src/utils/terminalShellEnvironment.ts
+++ b/src/utils/terminalShellEnvironment.ts
@@ -104,7 +104,10 @@ async function captureTerminalShellEnvironment(
 ): Promise<Record<string, string> | null> {
   if (
     process.platform === 'win32' ||
-    isEnvTruthy(baseEnv.CC_HAHA_DISABLE_TERMINAL_SHELL_ENV)
+    isEnvTruthy(baseEnv.CC_HAHA_DISABLE_TERMINAL_SHELL_ENV) ||
+    // Direct terminal launches already inherit shell env; spawning an
+    // interactive login shell here can interfere with the active TTY.
+    (process.stdin.isTTY && process.stdout.isTTY)
   ) {
     return null
   }