plit tui — terminal chat interface for Pipelit

[theuseless-ai]

Moved from plit-gw#69.

Overview

Implement plit tui — a terminal UI for chatting with Pipelit agents. Talks to Pipelit API directly (not through gateway).

Commands

plit tui                          # Interactive agent/workflow selection
plit tui --agent <slug>           # Direct agent selection
plit tui --agent <slug> --chat-id <id>  # Resume existing chat session

Architecture

TUI connects directly to Pipelit API (same as web frontend did). Gateway is not involved — it handles external adapter traffic only.

plit auth login --url http://localhost:8000  →  authenticates against Pipelit
plit tui  →  connects to Pipelit at stored URL
  REST:  POST /api/v1/workflows/{slug}/chat/
  WS:    /ws/?token=...  (real-time events)

Features

• Interactive agent/workflow selection (list available triggers)
• Real-time streaming via Pipelit WebSocket (/ws/?token= and /ws/executions/{execution_id}/)
• Chat history (load from LangGraph checkpoints)
• Activity indicator (node execution progress, tool calls)
• Markdown rendering for assistant messages
• Session management (list, resume, delete sessions)

Pipelit endpoints used

Chat (restored in #154):

• POST /api/v1/workflows/{slug}/chat/ — send message, start execution
• GET /api/v1/workflows/{slug}/chat/history — load history from checkpoints
• DELETE /api/v1/workflows/{slug}/chat/history — clear history

Already exist:

• GET /api/v1/workflows/ — list workflows/agents
• GET /api/v1/workflows/{slug}/ — get workflow detail + nodes
• POST /api/v1/auth/token/ — login
• WebSocket /ws/?token= — real-time events (chat_message, node_status, execution_completed)
• WebSocket /ws/executions/{execution_id}/ — per-execution streaming

Pipelit infrastructure still in place

• trigger_chat component (registered, functional)
• Conversation model (DB table)
• ChatMessageIn / ChatMessageOut schemas
• LangGraph checkpoint storage for conversation memory
• Thread ID format: {user_id}:{workflow_id}

TUI Library

ratatui + crossterm

Dependencies

• plit-gw#63 (plit auth login) — must be logged in
• Pipelit chat endpoints (restored in #154, verify in v0.3.9)