Need multi-pane, full-screen UI?
├─ YES → Use Textual
│        (widgets, containers, CSS styling, message passing)
│
Need advanced line editing, history, completions?
├─ YES → Use Prompt Toolkit
│        (PromptSession, FileHistory, Completers, key bindings)
│
Need both?
└─ Use Textual with Suggester API for input completion
   Or embed prompt_toolkit patterns in custom widgets

from textual.app import App, ComposeResult
from textual.widgets import Static, Header, Footer

class MyApp(App):
    CSS = """
    Screen { align: center middle; }
    #content { border: solid $primary; padding: 1 2; }
    """
    BINDINGS = [("q", "quit", "Quit"), ("d", "toggle_dark", "Dark Mode")]

    def compose(self) -> ComposeResult:
        yield Header()
        yield Static("Hello, Textual!", id="content")
        yield Footer()

    def action_toggle_dark(self) -> None:
        self.dark = not self.dark

if __name__ == "__main__":
    MyApp().run()

from prompt_toolkit import PromptSession
from prompt_toolkit.history import FileHistory
from prompt_toolkit.completion import WordCompleter

session = PromptSession(
    history=FileHistory(".history"),
    completer=WordCompleter(["help", "quit", "status", "run"]),
)

while True:
    text = session.prompt(">>> ")
    if text == "quit":
        break
    print(f"You entered: {text}")

Screen { background: $surface; }
#sidebar { dock: left; width: 25; }
.highlight { background: $accent; }
Widget:focus { border: thick $success; }

class MyWidget(Static):
    class Changed(Message):
        def __init__(self, value: str) -> None:
            self.value = value
            super().__init__()

    def update_value(self, value: str) -> None:
        self.post_message(self.Changed(value))

# In App:
def on_my_widget_changed(self, message: MyWidget.Changed) -> None:
    self.log(f"Changed to: {message.value}")

BINDINGS = [
    ("q", "quit", "Quit"),
    ("ctrl+s", "save", "Save"),
    ("ctrl+p", "command_palette", "Commands"),
]

def action_save(self) -> None:
    # Handle save
    pass

class MyApp(App):
    theme = "textual-dark"  # or "nord", "gruvbox", "tokyo-night"

from prompt_toolkit.history import FileHistory, InMemoryHistory

# Persistent across sessions
history = FileHistory("~/.myapp_history")

# In-memory only
history = InMemoryHistory()

from prompt_toolkit.completion import WordCompleter, NestedCompleter

# Simple word list
completer = WordCompleter(["red", "green", "blue"])

# Nested commands
completer = NestedCompleter.from_nested_dict({
    "show": {"status": None, "config": None},
    "set": {"verbose": {"on": None, "off": None}},
})

from prompt_toolkit.key_binding import KeyBindings

bindings = KeyBindings()

@bindings.add("c-x")
def exit_handler(event):
    event.app.exit()

session = PromptSession(key_bindings=bindings)

from prompt_toolkit.validation import Validator

validator = Validator.from_callable(
    lambda text: text.isdigit(),
    error_message="Must be a number",
)
text = prompt("Number: ", validator=validator)

import pytest
from my_app import MyApp

@pytest.mark.asyncio
async def test_button_click():
    app = MyApp()
    async with app.run_test() as pilot:
        await pilot.click("#my-button")
        assert app.query_one("#result").renderable == "Clicked!"

def test_app_snapshot(snap_compare):
    assert snap_compare("path/to/app.py", press=["tab", "enter"])

class MyApp(App):
    def __init__(self, mcp_client: Any) -> None:
        super().__init__()
        self.mcp_client = mcp_client

    async def load_data(self) -> None:
        result = await self.mcp_client.call_tool(
            "database_query",
            {"query": "SELECT * FROM items"}
        )
        # Update widgets with result

async def on_input_submitted(self, event: Input.Submitted) -> None:
    async for chunk in self.agent_client.run_task(event.value):
        self.query_one("#output", RichLog).write(chunk.content)