fix: skip init prompts when stdin is not a TTY

nitrostack/cli/main.py

@@ -1084,9 +1084,21 @@ def print_banner():
 ╚══════════════════════════════════════════════════════════╝\033[0m"""
     print(banner)
 
+def _stdin_is_interactive() -> bool:
+    """False for Studio/CI, which inherit an stdin that may never write."""
+    try:
+        return sys.stdin is not None and sys.stdin.isatty()
+    except Exception:
+        return False
+
+
 def _prompt(message: str, default: str = "") -> str:
     default_hint = f" [{default}]" if default else ""
     sys.stdout.write(f"\033[32m? \033[1;37m{message}:\033[0m{default_hint} ")
+    if not _stdin_is_interactive():
+        sys.stdout.write(f"{default}\n")
+        sys.stdout.flush()
+        return default
     sys.stdout.flush()
     try:
         value = sys.stdin.readline().strip()
@@ -1202,6 +1214,10 @@ def _upsert_env_var(lines, key, value):
 def _prompt_yes_no(message: str, default_yes: bool = True) -> bool:
     hint = "Y/n" if default_yes else "y/N"
     sys.stdout.write(f"\033[32m? \033[1;37m{message}:\033[0m ({hint}) ")
+    if not _stdin_is_interactive():
+        sys.stdout.write(("yes" if default_yes else "no") + "\n")
+        sys.stdout.flush()
+        return default_yes
     sys.stdout.flush()
     try:
         ans = sys.stdin.readline().strip().lower()
@@ -1262,6 +1278,9 @@ def init_project(name: str = None, template: str = None, skip_install: bool = Fa
 
     # 2. Overwrite check
     if os.path.exists(name):
+        if not _stdin_is_interactive():
+            print(f"Error: Directory '{name}' already exists.")
+            sys.exit(1)
         sys.stdout.write(f"\033[32m? \033[1;37mDirectory '{name}' already exists. Overwrite?\033[0m (Yes/No) [No]: ")
         sys.stdout.flush()
         ans = sys.stdin.readline().strip().lower()
@@ -1276,7 +1295,7 @@ def init_project(name: str = None, template: str = None, skip_install: bool = Fa
     else:
         template = _resolve_template(template)
 
-    # 4. Description and Author
+    # 4. Description and Author (defaults when stdin is not a TTY)
     description = _prompt("Description", "My awesome MCP server")
     author = _prompt("Author", "developer")
 

tests/test_cli.py

@@ -18,6 +18,14 @@
 
 sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
 
+
+class _TtyInput(io.StringIO):
+    """Scripted answers for prompts, which only read stdin when it is a TTY."""
+
+    def isatty(self):
+        return True
+
+
 from nitrostack.cli.main import (
     DEFAULT_MCP_PORT,
     DEFAULT_PROJECT_NAME,
@@ -124,7 +132,7 @@ def test_init_with_name_and_explicit_template():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("A test server\nTester\n")
+        sys.stdin = _TtyInput("A test server\nTester\n")
         init_project("cli-demo", template="python-starter", skip_install=True)
         project = os.path.join(tmp, "cli-demo")
         assert os.path.isfile(os.path.join(project, "main.py"))
@@ -151,7 +159,7 @@ def test_init_prompts_for_name_when_omitted():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("prompted-server\n\n\n")
+        sys.stdin = _TtyInput("prompted-server\n\n\n")
         init_project(None, template="python-starter", skip_install=True)
         assert os.path.isdir(os.path.join(tmp, "prompted-server"))
         print("Success! Missing name is asked on the next readline.")
@@ -167,7 +175,7 @@ def test_init_default_name_when_blank_readline():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("\n\n\n")
+        sys.stdin = _TtyInput("\n\n\n")
         init_project(None, template="python-pizzaz", skip_install=True)
         assert os.path.isdir(os.path.join(tmp, DEFAULT_PROJECT_NAME))
         env_text = open(os.path.join(tmp, DEFAULT_PROJECT_NAME, ".env"), encoding="utf-8").read()
@@ -191,7 +199,7 @@ def test_init_python_oauth_template():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("\n\n")
+        sys.stdin = _TtyInput("\n\n")
         init_project("oauth-demo", template="python-oauth", skip_install=True)
         project = os.path.join(tmp, "oauth-demo")
         assert os.path.isfile(os.path.join(project, "OAUTH_SETUP.md"))
@@ -280,7 +288,7 @@ def test_init_port_and_widget_flags_override_defaults():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("\n\n")
+        sys.stdin = _TtyInput("\n\n")
         init_project(
             "ports-demo",
             template="python-starter",
@@ -308,7 +316,7 @@ def test_init_install_dependencies_prompt_no():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("desc\nauthor\nn\n")
+        sys.stdin = _TtyInput("desc\nauthor\nn\n")
         with patch("nitrostack.cli.main.install_dependencies") as pip_install:
             init_project("no-npm", template="python-starter")
             pip_install.assert_not_called()
@@ -365,12 +373,25 @@ def test_run_npm_does_not_use_shell():
     print("Success! npm is invoked as an argv list without shell=True.")
 
 
+def test_prompts_return_defaults_without_tty():
+    """Studio and CI inherit a non-TTY stdin: prompts must not read from it."""
+    original = sys.stdin
+    try:
+        sys.stdin = io.StringIO("typed\n")
+        assert _prompt("Name", "fallback") == "fallback"
+        assert _prompt_template() == "python-starter"
+        assert _prompt_yes_no("Install", default_yes=False) is False
+        assert sys.stdin.read() == "typed\n"
+        print("Success! prompts use defaults and leave a non-TTY stdin unread.")
+    finally:
+        sys.stdin = original
+
 def test_prompt_uses_value_or_default():
     original = sys.stdin
     try:
-        sys.stdin = io.StringIO("custom\n")
+        sys.stdin = _TtyInput("custom\n")
         assert _prompt("Name", "fallback") == "custom"
-        sys.stdin = io.StringIO("\n")
+        sys.stdin = _TtyInput("\n")
         assert _prompt("Name", "fallback") == "fallback"
 
         class Boom:
@@ -394,13 +415,13 @@ def test_resolve_template_accepts_official_names():
 def test_prompt_template_choice_and_explicit_name():
     original = sys.stdin
     try:
-        sys.stdin = io.StringIO("2\n")
+        sys.stdin = _TtyInput("2\n")
         assert _prompt_template() == "python-pizzaz"
-        sys.stdin = io.StringIO("python-oauth\n")
+        sys.stdin = _TtyInput("python-oauth\n")
         assert _prompt_template() == "python-oauth"
-        sys.stdin = io.StringIO("nope\n3\n")
+        sys.stdin = _TtyInput("nope\n3\n")
         assert _prompt_template() == "python-oauth"
-        sys.stdin = io.StringIO("\n")
+        sys.stdin = _TtyInput("\n")
         assert _prompt_template() == "python-starter"
         print("Success! _prompt_template handles numbers, names, retries, and default.")
     finally:
@@ -458,19 +479,19 @@ def test_upsert_env_var_replaces_and_appends():
 def test_prompt_yes_no_answers():
     original = sys.stdin
     try:
-        sys.stdin = io.StringIO("\n")
+        sys.stdin = _TtyInput("\n")
         assert _prompt_yes_no("Install", default_yes=True) is True
-        sys.stdin = io.StringIO("\n")
+        sys.stdin = _TtyInput("\n")
         assert _prompt_yes_no("Install", default_yes=False) is False
-        sys.stdin = io.StringIO("y\n")
+        sys.stdin = _TtyInput("y\n")
         assert _prompt_yes_no("Install", default_yes=False) is True
-        sys.stdin = io.StringIO("yes\n")
+        sys.stdin = _TtyInput("yes\n")
         assert _prompt_yes_no("Install") is True
-        sys.stdin = io.StringIO("n\n")
+        sys.stdin = _TtyInput("n\n")
         assert _prompt_yes_no("Install") is False
-        sys.stdin = io.StringIO("no\n")
+        sys.stdin = _TtyInput("no\n")
         assert _prompt_yes_no("Install") is False
-        sys.stdin = io.StringIO("maybe\n")
+        sys.stdin = _TtyInput("maybe\n")
         assert _prompt_yes_no("Install", default_yes=True) is True
         print("Success! _prompt_yes_no handles Y/n, empty default, and unknown input.")
     finally:
@@ -543,7 +564,7 @@ def test_init_project_rejects_blank_name_and_overwrite_cancel():
         except SystemExit:
             pass
         os.mkdir("taken")
-        sys.stdin = io.StringIO("n\n")
+        sys.stdin = _TtyInput("n\n")
         try:
             init_project("taken", template="python-starter", skip_install=True)
             raise AssertionError("overwrite cancel should exit")
@@ -567,14 +588,14 @@ def test_init_project_overwrite_and_install_yes_calls_npm():
         os.chdir(tmp)
         os.mkdir("taken")
         open(os.path.join("taken", "old.txt"), "w", encoding="utf-8").write("x")
-        sys.stdin = io.StringIO("y\ndesc\nauthor\n")
+        sys.stdin = _TtyInput("y\ndesc\nauthor\n")
         with patch("nitrostack.cli.main._run_npm") as npm:
             init_project("taken", template="python-starter", skip_install=True)
             npm.assert_not_called()
         assert os.path.isfile(os.path.join("taken", "main.py"))
         assert not os.path.exists(os.path.join("taken", "old.txt"))
 
-        sys.stdin = io.StringIO("d\na\nY\n")
+        sys.stdin = _TtyInput("d\na\nY\n")
         with patch("nitrostack.cli.main.install_dependencies") as pip_install:
             with patch("nitrostack.cli.main._run_npm") as npm:
                 init_project("installed", template="python-starter")
@@ -583,7 +604,7 @@ def test_init_project_overwrite_and_install_yes_calls_npm():
                 npm.assert_not_called()
         assert os.path.isfile(os.path.join("installed", "widgets", "out", "calculator-result.html"))
 
-        sys.stdin = io.StringIO("d\na\n\n")
+        sys.stdin = _TtyInput("d\na\n\n")
         with patch("nitrostack.cli.main.install_dependencies") as pip_install:
             init_project("installed-enter", template="python-starter")
             pip_install.assert_called_once()
@@ -931,7 +952,7 @@ def test_init_rewrites_pyproject_identity_and_copies_uv_files(template):
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("Rewritten description\nTester\n")
+        sys.stdin = _TtyInput("Rewritten description\nTester\n")
         init_project("My_App", template=template, skip_install=True)
         project = os.path.join(tmp, "My_App")
         pyproject = open(os.path.join(project, "pyproject.toml"), encoding="utf-8").read()
@@ -960,7 +981,7 @@ def test_init_runs_uv_lock_in_project_dir():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("\n\n")
+        sys.stdin = _TtyInput("\n\n")
         with patch.dict(os.environ, {}, clear=False):
             os.environ.pop("NITROSTACK_SKIP_UV_LOCK", None)
             with patch("nitrostack.cli.install._uv_bin", return_value="/usr/bin/uv"):
@@ -982,7 +1003,7 @@ def test_init_succeeds_when_uv_is_missing():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("\n\n")
+        sys.stdin = _TtyInput("\n\n")
         with patch.dict(os.environ, {}, clear=False):
             os.environ.pop("NITROSTACK_SKIP_UV_LOCK", None)
             with patch("nitrostack.cli.install._uv_bin", return_value=None):
@@ -1001,7 +1022,7 @@ def test_init_succeeds_when_uv_lock_fails():
     original_stdin = sys.stdin
     try:
         os.chdir(tmp)
-        sys.stdin = io.StringIO("\n\n")
+        sys.stdin = _TtyInput("\n\n")
         with patch.dict(os.environ, {}, clear=False):
             os.environ.pop("NITROSTACK_SKIP_UV_LOCK", None)
             with patch("nitrostack.cli.install._uv_bin", return_value="/usr/bin/uv"):

tests/test_cli_studio_noninteractive.py

@@ -0,0 +1,120 @@
+"""Studio generate-wizard contract: init must not block on inherited stdin.
+
+NitroStudio step 4 of 5 used to hang because `nitrostack-py init --skip-install`
+still prompted Description/Author via readline() on an inherited stdin that
+never wrote. --skip-install only skips dependency install.
+
+These tests spawn the real CLI with stdin left open (PIPE, never written, never
+closed) so they fail if prompts return.
+"""
+from __future__ import annotations
+
+import os
+import subprocess
+import sys
+import tempfile
+import threading
+import time
+from pathlib import Path
+
+ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
+
+
+def _cli_env():
+    env = os.environ.copy()
+    env["PYTHONPATH"] = ROOT
+    env["PYTHONUNBUFFERED"] = "1"
+    return env
+
+
+def _run_init_open_stdin(cwd: str, extra_args: list[str], timeout: float = 20.0):
+    """Spawn init with stdin PIPE left open. Do not write or close it."""
+    proc = subprocess.Popen(
+        [sys.executable, "-m", "nitrostack.cli.main", *extra_args],
+        cwd=cwd,
+        stdin=subprocess.PIPE,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        env=_cli_env(),
+    )
+    chunks_out: list[bytes] = []
+    chunks_err: list[bytes] = []
+
+    def _drain(stream, bucket):
+        try:
+            while True:
+                data = stream.read(4096)
+                if not data:
+                    break
+                bucket.append(data)
+        except Exception:
+            pass
+
+    threading.Thread(target=_drain, args=(proc.stdout, chunks_out), daemon=True).start()
+    threading.Thread(target=_drain, args=(proc.stderr, chunks_err), daemon=True).start()
+
+    deadline = time.time() + timeout
+    while proc.poll() is None:
+        if time.time() > deadline:
+            proc.kill()
+            proc.wait(timeout=5)
+            stdout = b"".join(chunks_out).decode("utf-8", "replace")
+            stderr = b"".join(chunks_err).decode("utf-8", "replace")
+            raise TimeoutError(
+                f"CLI hung for {timeout}s on open unused stdin\n"
+                f"stdout:\n{stdout}\nstderr:\n{stderr}"
+            )
+        time.sleep(0.05)
+
+    stdout = b"".join(chunks_out).decode("utf-8", "replace")
+    stderr = b"".join(chunks_err).decode("utf-8", "replace")
+    return proc.returncode, stdout, stderr
+
+
+def test_init_skip_install_does_not_hang_on_open_unused_stdin():
+    tmp = tempfile.mkdtemp(prefix="nitro-cli-studio-")
+    try:
+        code, stdout, stderr = _run_init_open_stdin(
+            tmp,
+            ["init", "studio_demo", "--template", "python-starter", "--skip-install"],
+        )
+        assert code == 0, f"exit {code}\n{stdout}\n{stderr}"
+        project = Path(tmp) / "studio_demo"
+        assert (project / "main.py").is_file()
+        assert (project / "app_module.py").is_file()
+        req = (project / "requirements.txt").read_text(encoding="utf-8")
+        assert "nitrostack" in req.lower()
+    finally:
+        import shutil
+
+        shutil.rmtree(tmp, ignore_errors=True)
+
+
+def test_init_without_args_uses_defaults_on_open_unused_stdin():
+    tmp = tempfile.mkdtemp(prefix="nitro-cli-noargs-")
+    try:
+        code, stdout, stderr = _run_init_open_stdin(tmp, ["init", "--skip-install"])
+        assert code == 0, f"exit {code}\n{stdout}\n{stderr}"
+        project = Path(tmp) / "my-mcp-server"
+        assert (project / "main.py").is_file()
+    finally:
+        import shutil
+
+        shutil.rmtree(tmp, ignore_errors=True)
+
+def test_init_existing_dir_exits_without_overwrite_prompt():
+    tmp = tempfile.mkdtemp(prefix="nitro-cli-exists-")
+    try:
+        os.mkdir(os.path.join(tmp, "already"))
+        code, stdout, stderr = _run_init_open_stdin(
+            tmp,
+            ["init", "already", "--template", "python-starter", "--skip-install"],
+            timeout=15.0,
+        )
+        assert code != 0
+        combined = (stdout + stderr).lower()
+        assert "already exists" in combined
+    finally:
+        import shutil
+
+        shutil.rmtree(tmp, ignore_errors=True)

tests/test_project_templates.py

@@ -36,7 +36,9 @@ def run(args, cwd, *, python=None, installed=False):
 
 @pytest.mark.parametrize("choice,expected", [("4", "python-enterprise-search"), ("5", "python-code-mode"), ("python-enterprise-search", "python-enterprise-search"), ("python-code-mode", "python-code-mode")])
 def test_new_template_prompt_choices(choice, expected, monkeypatch):
-    monkeypatch.setattr(sys, "stdin", io.StringIO(choice + "\n"))
+    stdin = io.StringIO(choice + "\n")
+    stdin.isatty = lambda: True  # prompts read only from a TTY
+    monkeypatch.setattr(sys, "stdin", stdin)
     assert _prompt_template() == expected
     assert OFFICIAL_TEMPLATES[expected] in {"enterprise-search", "code-mode"}