Chapter 9: A Better TUI

The chat.rs CLI works, but it dumps plain text and shows every tool call. A real coding agent deserves markdown rendering, a thinking spinner, and collapsed tool calls when the agent gets busy.

See mini-claw-code/examples/tui.rs for a reference implementation. It uses:

• termimad for inline markdown rendering in the terminal.
• crossterm for raw terminal mode (used by the arrow-key selection UI in Chapter 11).
• An animated spinner (⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏) that ticks while the agent thinks.
• Collapsed tool calls: after 3 tool calls, subsequent ones are collapsed into a ... and N more counter to keep the output clean.

The TUI builds on the AgentEvent stream from StreamingAgent (Chapter 10). The event loop uses tokio::select! to multiplex three sources:

1. Agent events (AgentEvent::TextDelta, ToolCall, Done, Error) – render streaming text, tool summaries, or final output.
2. User input requests from AskTool (Chapter 11) – pause the spinner and show a text prompt or arrow-key selection list.
3. Timer ticks – advance the spinner animation.

This chapter is exposition only – no code to write. Read through examples/tui.rs to see how the pieces fit together, or ask your mini-claw-code agent to build a TUI for you.