feat(cli): rewrite input layer with prompt_toolkit and polish UI

- Replaces fragile input() hacks with robust prompt_toolkit.PromptSession
- Native support for multiline paste, history, and clean display
- Restores animated spinner in _thinking_ctx (now safe)
- Replaces boxed Panel with clean header for easier copying
- Adds prompt-toolkit dependency
- Adds new unit tests for input layer

nanobot/cli/commands.py

@@ -1,7 +1,6 @@
 """CLI commands for nanobot."""
 
 import asyncio
-import atexit
 import os
 import signal
 from pathlib import Path
@@ -15,6 +14,11 @@ from rich.panel import Panel
 from rich.table import Table
 from rich.text import Text
 
+from prompt_toolkit import PromptSession
+from prompt_toolkit.formatted_text import HTML
+from prompt_toolkit.history import FileHistory
+from prompt_toolkit.patch_stdout import patch_stdout
+
 from nanobot import __version__, __logo__
 
 app = typer.Typer(
@@ -27,13 +31,10 @@ console = Console()
 EXIT_COMMANDS = {"exit", "quit", "/exit", "/quit", ":q"}
 
 # ---------------------------------------------------------------------------
-# Lightweight CLI input: readline for arrow keys / history, termios for flush
+# CLI input: prompt_toolkit for editing, paste, history, and display
 # ---------------------------------------------------------------------------
 
-_READLINE = None
+_PROMPT_SESSION: PromptSession | None = None
-_HISTORY_FILE: Path | None = None
-_HISTORY_HOOK_REGISTERED = False
-_USING_LIBEDIT = False
 _SAVED_TERM_ATTRS = None  # original termios settings, restored on exit
 
 
@@ -64,15 +65,6 @@ def _flush_pending_tty_input() -> None:
         return
 
 
-def _save_history() -> None:
-    if _READLINE is None or _HISTORY_FILE is None:
-        return
-    try:
-        _READLINE.write_history_file(str(_HISTORY_FILE))
-    except Exception:
-        return
-
-
 def _restore_terminal() -> None:
     """Restore terminal to its original state (echo, line buffering, etc.)."""
     if _SAVED_TERM_ATTRS is None:
@@ -84,11 +76,11 @@ def _restore_terminal() -> None:
         pass
 
 
-def _enable_line_editing() -> None:
+def _init_prompt_session() -> None:
-    """Enable readline for arrow keys, line editing, and persistent history."""
+    """Create the prompt_toolkit session with persistent file history."""
-    global _READLINE, _HISTORY_FILE, _HISTORY_HOOK_REGISTERED, _USING_LIBEDIT, _SAVED_TERM_ATTRS
+    global _PROMPT_SESSION, _SAVED_TERM_ATTRS
 
-    # Save terminal state before readline touches it
+    # Save terminal state so we can restore it on exit
     try:
         import termios
         _SAVED_TERM_ATTRS = termios.tcgetattr(sys.stdin.fileno())
@@ -97,59 +89,22 @@ def _enable_line_editing() -> None:
 
     history_file = Path.home() / ".nanobot" / "history" / "cli_history"
     history_file.parent.mkdir(parents=True, exist_ok=True)
-    _HISTORY_FILE = history_file
 
-    try:
+    _PROMPT_SESSION = PromptSession(
-        import readline
+        history=FileHistory(str(history_file)),
-    except ImportError:
+        enable_open_in_editor=False,
-        return
+        multiline=False,   # Enter submits (single line mode)
-
+    )
-    _READLINE = readline
-    _USING_LIBEDIT = "libedit" in (readline.__doc__ or "").lower()
-
-    try:
-        if _USING_LIBEDIT:
-            readline.parse_and_bind("bind ^I rl_complete")
-        else:
-            readline.parse_and_bind("tab: complete")
-        readline.parse_and_bind("set editing-mode emacs")
-    except Exception:
-        pass
-
-    try:
-        readline.read_history_file(str(history_file))
-    except Exception:
-        pass
-
-    if not _HISTORY_HOOK_REGISTERED:
-        atexit.register(_save_history)
-        _HISTORY_HOOK_REGISTERED = True
-
-
-def _prompt_text() -> str:
-    """Build a readline-friendly colored prompt."""
-    if _READLINE is None:
-        return "You: "
-    # libedit on macOS does not honor GNU readline non-printing markers.
-    if _USING_LIBEDIT:
-        return "\033[1;34mYou:\033[0m "
-    return "\001\033[1;34m\002You:\001\033[0m\002 "
 
 
 def _print_agent_response(response: str, render_markdown: bool) -> None:
-    """Render assistant response with consistent terminal styling."""
+    """Render assistant response with clean, copy-friendly header."""
     content = response or ""
     body = Markdown(content) if render_markdown else Text(content)
     console.print()
-    console.print(
+    # Use a simple header instead of a Panel box, making it easier to copy text
-        Panel(
+    console.print(f"{__logo__} [bold cyan]nanobot[/bold cyan]")
-            body,
+    console.print(body)
-            title=f"{__logo__} nanobot",
-            title_align="left",
-            border_style="cyan",
-            padding=(0, 1),
-        )
-    )
     console.print()
 
 
@@ -159,13 +114,25 @@ def _is_exit_command(command: str) -> bool:
 
 
 async def _read_interactive_input_async() -> str:
-    """Read user input with arrow keys and history (runs input() in a thread)."""
+    """Read user input using prompt_toolkit (handles paste, history, display).
+
+    prompt_toolkit natively handles:
+    - Multiline paste (bracketed paste mode)
+    - History navigation (up/down arrows)
+    - Clean display (no ghost characters or artifacts)
+    """
+    if _PROMPT_SESSION is None:
+        raise RuntimeError("Call _init_prompt_session() first")
     try:
-        return await asyncio.to_thread(input, _prompt_text())
+        with patch_stdout():
+            return await _PROMPT_SESSION.prompt_async(
+                HTML("<b fg='ansiblue'>You:</b> "),
+            )
     except EOFError as exc:
         raise KeyboardInterrupt from exc
 
 
+
 def version_callback(value: bool):
     if value:
         console.print(f"{__logo__} nanobot v{__version__}")
@@ -473,6 +440,7 @@ def agent(
         if logs:
             from contextlib import nullcontext
             return nullcontext()
+        # Animated spinner is safe to use with prompt_toolkit input handling
         return console.status("[dim]nanobot is thinking...[/dim]", spinner="dots")
 
     if message:
@@ -485,13 +453,10 @@ def agent(
         asyncio.run(run_once())
     else:
         # Interactive mode
-        _enable_line_editing()
+        _init_prompt_session()
         console.print(f"{__logo__} Interactive mode (type [bold]exit[/bold] or [bold]Ctrl+C[/bold] to quit)\n")
 
-        # input() runs in a worker thread that can't be cancelled.
-        # Without this handler, asyncio.run() would hang waiting for it.
         def _exit_on_sigint(signum, frame):
-            _save_history()
             _restore_terminal()
             console.print("\nGoodbye!")
             os._exit(0)
@@ -508,7 +473,6 @@ def agent(
                         continue
 
                     if _is_exit_command(command):
-                        _save_history()
                         _restore_terminal()
                         console.print("\nGoodbye!")
                         break
@@ -517,12 +481,10 @@ def agent(
                         response = await agent_loop.process_direct(user_input, session_id)
                     _print_agent_response(response, render_markdown=markdown)
                 except KeyboardInterrupt:
-                    _save_history()
                     _restore_terminal()
                     console.print("\nGoodbye!")
                     break
                 except EOFError:
-                    _save_history()
                     _restore_terminal()
                     console.print("\nGoodbye!")
                     break

pyproject.toml

@@ -37,6 +37,7 @@ dependencies = [
     "slack-sdk>=3.26.0",
     "qq-botpy>=1.0.0",
     "python-socks[asyncio]>=2.4.0",
+    "prompt-toolkit>=3.0.0",
 ]
 
 [project.optional-dependencies]

tests/test_cli_input.py

@@ -0,0 +1,58 @@
+import asyncio
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+from prompt_toolkit.formatted_text import HTML
+
+from nanobot.cli import commands
+
+
+@pytest.fixture
+def mock_prompt_session():
+    """Mock the global prompt session."""
+    mock_session = MagicMock()
+    mock_session.prompt_async = AsyncMock()
+    with patch("nanobot.cli.commands._PROMPT_SESSION", mock_session):
+        yield mock_session
+
+
+@pytest.mark.asyncio
+async def test_read_interactive_input_async_returns_input(mock_prompt_session):
+    """Test that _read_interactive_input_async returns the user input from prompt_session."""
+    mock_prompt_session.prompt_async.return_value = "hello world"
+
+    result = await commands._read_interactive_input_async()
+    
+    assert result == "hello world"
+    mock_prompt_session.prompt_async.assert_called_once()
+    args, _ = mock_prompt_session.prompt_async.call_args
+    assert isinstance(args[0], HTML)  # Verify HTML prompt is used
+
+
+@pytest.mark.asyncio
+async def test_read_interactive_input_async_handles_eof(mock_prompt_session):
+    """Test that EOFError converts to KeyboardInterrupt."""
+    mock_prompt_session.prompt_async.side_effect = EOFError()
+
+    with pytest.raises(KeyboardInterrupt):
+        await commands._read_interactive_input_async()
+
+
+def test_init_prompt_session_creates_session():
+    """Test that _init_prompt_session initializes the global session."""
+    # Ensure global is None before test
+    commands._PROMPT_SESSION = None
+    
+    with patch("nanobot.cli.commands.PromptSession") as MockSession, \
+         patch("nanobot.cli.commands.FileHistory") as MockHistory, \
+         patch("pathlib.Path.home") as mock_home:
+        
+        mock_home.return_value = MagicMock()
+        
+        commands._init_prompt_session()
+        
+        assert commands._PROMPT_SESSION is not None
+        MockSession.assert_called_once()
+        _, kwargs = MockSession.call_args
+        assert kwargs["multiline"] is False
+        assert kwargs["enable_open_in_editor"] is False