Rich + prompt_toolkit Compatibility

The Problem 🚫

Rich and prompt_toolkit don’t work well together out of the box:

  • Rich uses ANSI escape codes and special markup for beautiful terminal output
  • prompt_toolkit has its own text rendering system with buffers and layout management
  • Conflict: Rich’s formatting codes appear as messy, unrendered text in prompt_toolkit buffers

Before (Messy Output): 

[20:43:22] 🤖 devops_agent: [bold green]Hello![/bold green] How can I assist you today?
╭───────────────────────────────────────── 🧠 Model Usage (with Thinking) ─────────────────────────────────────────╮
│ Token Usage: Prompt: 2475, [cyan]Thinking: 33[/cyan], Output: 9, Total: 2517                                   │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

After (Clean Output): 

[20:43:22] 🤖 devops_agent: Hello! How can I assist you today?
Token Usage: Prompt: 2475, Thinking: 33, Output: 9, Total: 2517

The Solution ✅

1. Text Sanitization in TextualCLI

Added a _add_to_output() method that converts Rich content to plain text:

def _add_to_output(self, text: str, style: str = ""):
    """Add text to the output buffer, stripping Rich formatting."""
    from rich.console import Console
    from io import StringIO
    
    # Create a temporary console to render Rich content to plain text
    string_io = StringIO()
    temp_console = Console(file=string_io, force_terminal=False, width=80)
    
    # Try to render as Rich content, fall back to plain text
    try:
        temp_console.print(text)
        clean_text = string_io.getvalue().rstrip('\n')
    except:
        # If Rich rendering fails, use plain text
        clean_text = text
    
    timestamp = datetime.now().strftime("%H:%M:%S")
    formatted_text = f"[{timestamp}] {clean_text}\n"
    
    current_text = self.output_buffer.text
    self.output_buffer.text = current_text + formatted_text
    
    # Auto-scroll to bottom
    self.output_buffer.cursor_position = len(self.output_buffer.text)

2. ANSI Code Stripping Function

Added _strip_rich_markup() to remove any remaining formatting:

def _strip_rich_markup(text: str) -> str:
    """Strip Rich markup and ANSI codes from text for clean prompt_toolkit display."""
    import re
    from rich.console import Console
    from io import StringIO
    
    try:
        # Create a console that outputs plain text
        string_io = StringIO()
        temp_console = Console(file=string_io, force_terminal=False, width=120, legacy_windows=False)
        
        # Print the text and capture plain output
        temp_console.print(text, markup=False, highlight=False)
        clean_text = string_io.getvalue().rstrip('\n')
        
        # Additional cleanup of any remaining ANSI codes
        ansi_escape = re.compile(r'\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])')
        clean_text = ansi_escape.sub('', clean_text)
        
        return clean_text
        
    except Exception:
        # Fallback: basic ANSI code removal
        ansi_escape = re.compile(r'\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])')
        return ansi_escape.sub('', text)

3. Agent Response Processing

Modified the agent response handler to clean text before display:

async def _process_agent_responses(agent_gen, cli):
    """Process agent responses and add them to the CLI output."""
    async for event in agent_gen:
        if event.content and event.content.parts:
            if text := ''.join(part.text or '' for part in event.content.parts):
                # Filter out thought content to prevent duplication
                filtered_text = _filter_thought_content(text)
                if filtered_text.strip():
                    # Strip any Rich markup/ANSI codes for clean prompt_toolkit display
                    clean_text = _strip_rich_markup(filtered_text)
                    cli.add_agent_output(clean_text, event.author)

Technical Approach 🔧

Two-Stage Cleaning Process

  1. Rich Console Rendering: Use Rich’s own console to render markup to plain text
  2. ANSI Code Removal: Strip any remaining escape sequences with regex

Fallback Strategy

  • Primary: Rich console rendering with force_terminal=False
  • Fallback: Regex-based ANSI code removal
  • Final: Raw text if all else fails

Compatibility Layer

The solution acts as a compatibility layer:

Rich Formatted Text → Rich Console (plain) → ANSI Stripper → prompt_toolkit Buffer
     ↓                      ↓                    ↓                    ↓
[bold]Hello[/bold]   →   Hello   →   Hello   →   Clean Display

Benefits 🎉

For Users

  • ✅ Clean, readable output in the Textual CLI
  • ✅ No formatting artifacts or escape codes
  • ✅ Consistent appearance across different terminals
  • ✅ Preserved functionality of both Rich and prompt_toolkit

For Developers

  • ✅ Use Rich freely in agent code without compatibility concerns
  • ✅ Automatic conversion - no manual text processing needed
  • ✅ Backwards compatible - existing code continues to work
  • ✅ Error resilient - graceful fallbacks if conversion fails

Configuration Options 🛠️

Console Width 

temp_console = Console(file=string_io, force_terminal=False, width=80)
  • Controls text wrapping in the output
  • Adjustable based on terminal size

Rich Features Disabled 

temp_console.print(text, markup=False, highlight=False)
  • Disables Rich markup processing
  • Disables syntax highlighting
  • Ensures plain text output

ANSI Escape Pattern 

ansi_escape = re.compile(r'\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])')
  • Comprehensive ANSI escape sequence matching
  • Removes colors, cursor movements, formatting codes

Usage Examples 📝

Before (Messy) 

Agent Output: [bold red]Error:[/bold red] Connection failed
[33mWarning:[0m Retrying connection...
╭─ Status ─╮
│ [32m✓[0m │
╰──────────╯

After (Clean) 

Agent Output: Error: Connection failed  
Warning: Retrying connection...
Status: ✓

Testing 🧪 

# Test the clean output
uv run agent run agents.devops --tui

# Should now display:
# - Clean, readable text
# - No ANSI escape codes
# - No Rich markup artifacts
# - Proper text wrapping

Future Enhancements 🚀

  1. Configurable width: Auto-detect terminal width
  2. Selective formatting: Preserve some basic formatting (bold, colors)
  3. Rich integration: Use prompt_toolkit’s FormattedText for Rich-like styling
  4. Performance optimization: Cache rendered text for repeated content

This solution enables seamless integration between Rich’s powerful formatting capabilities and prompt_toolkit’s advanced UI features, giving you the best of both worlds! 🎯