BTerminal/docs/phases.md

BTerminal v2 — Implementation Phases

See task_plan.md for architecture decisions, error handling, and testing strategy.

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Phase 1: Project Scaffolding [status: complete] — MVP

• Create feature branch v2-mission-control
• Initialize Tauri 2.x project with Svelte 5 frontend
• Project structure (see below)
• Basic Tauri window with Catppuccin Mocha CSS variables
• Verify Tauri builds and launches on target system
• Set up dev scripts (dev, build, lint)

File Structure

bterminal-v2/
  src-tauri/
    src/
      main.rs              # Tauri app entry
      pty.rs               # PTY management (portable-pty, not plugin)
      sidecar.rs           # Node.js sidecar lifecycle (spawn, restart, health)
      watcher.rs           # File watcher for markdown viewer
      session.rs           # Session persistence (SQLite via rusqlite)
    Cargo.toml
  src/
    App.svelte             # Root layout
    lib/
      components/
        Layout/
          TilingGrid.svelte    # Dynamic tiling manager
          PaneContainer.svelte # Individual pane wrapper
          PaneHeader.svelte    # Pane title bar with controls
        Terminal/
          TerminalPane.svelte  # xterm.js terminal pane
        Agent/
          AgentPane.svelte     # SDK agent structured output
          AgentTree.svelte     # Subagent tree visualization
          ToolCallCard.svelte  # Individual tool call display
        Markdown/
          MarkdownPane.svelte  # Live markdown file viewer
        Sidebar/
          SessionList.svelte   # Session browser
      stores/
        sessions.svelte.ts   # Session state ($state runes)
        agents.svelte.ts     # Active agent tracking
        layout.svelte.ts     # Pane layout state
      adapters/
        sdk-messages.ts      # SDK message abstraction layer
        pty-bridge.ts        # PTY IPC wrapper
      styles/
        catppuccin.css       # Theme CSS variables
    app.css
  sidecar/
    agent-runner.ts          # Node.js sidecar entry point
    package.json             # Agent SDK dependency
    esbuild.config.ts        # Bundle to single file
  package.json
  svelte.config.js
  vite.config.ts
  tauri.conf.json

Key change from v1: Using portable-pty directly from Rust instead of tauri-plugin-pty (38-star community plugin). portable-pty is well-maintained (used by WezTerm). More work upfront, more reliable long-term.

---

Phase 2: Terminal Pane + Layout [status: complete] — MVP

Layout (responsive)

32:9 (5120px) — full density:

+--------+------------------------------------+--------+
|Sidebar |  2-4 panes, CSS Grid, resizable    | Right  |
| 260px  |                                     | 380px  |
+--------+------------------------------------+--------+

16:9 (1920px) — degraded but functional:

+--------+-------------------------+
|Sidebar |  1-2 panes              |  (right panel collapses to overlay)
| 240px  |                         |
+--------+-------------------------+

• CSS Grid layout with sidebar + main area + optional right panel
• Responsive breakpoints (ultrawide / standard / narrow)
• Pane resize via drag handles (deferred — current presets sufficient for MVP)
• Layout presets: 1-col, 2-col, 3-col, 2x2, master+stack
• Save/restore layout to SQLite (Phase 4)
• Keyboard: Ctrl+1-4 focus pane, Ctrl+N new terminal

Terminal

• xterm.js with Canvas addon (explicit — no WebGL dependency)
• Catppuccin Mocha theme for xterm.js
• PTY spawn from Rust (portable-pty), stream to frontend via Tauri events
• Terminal resize -> PTY resize (100ms debounce)
• Copy/paste (Ctrl+Shift+C/V) — deferred
• SSH session: spawn ssh command in PTY (via shell args)
• Local shell: spawn user's $SHELL
• Claude Code CLI: spawn claude in PTY (via shell args)

Milestone: After Phase 2, we have a working multi-pane terminal. Usable as a daily driver even without agent features.

---

Phase 3: Agent SDK Integration [status: in_progress] — MVP

Backend

• Node.js sidecar: spawns claude CLI with --output-format stream-json (not Agent SDK query() — avoids npm dep + version churn)
• Sidecar communication: Rust spawns Node.js, stdio NDJSON
• Sidecar lifecycle: auto-start on app launch, shutdown on exit
• Sidecar lifecycle: detect crash, offer restart in UI
• Tauri commands: agent_query, agent_stop, agent_ready

Frontend

• SDK message adapter: parses stream-json into 9 typed AgentMessage types (abstraction layer)
• Agent bridge: Tauri IPC adapter (invoke + event listeners)
• Agent dispatcher: singleton routing sidecar events to store
• Agent store: session state, message history, cost tracking (Svelte 5 $state)
• Agent pane: renders structured messages
  • Text -> plain text (markdown rendering deferred)
  • Tool calls -> collapsible cards (tool name + input)
  • Tool results -> collapsible cards
  • Thinking -> collapsible details
  • Init -> model badge
  • Cost -> USD/tokens/turns/duration summary
  • Errors -> highlighted error card
  • Subagent spawn -> tree node + optional new pane (Phase 5)
• Agent status indicator (starting/running/done/error)
• Start/stop agent from UI (prompt form + stop button)
• Auto-scroll with scroll-lock on user scroll-up
• Session resume (SDK resume: sessionId)
• Keyboard: Ctrl+Shift+N new agent
• Sidebar: agent session button

Milestone: After Phase 3, we have the core differentiator. SDK agents run in structured panes alongside raw terminals.

---

Phase 4: Session Management + Markdown Viewer [status: not_started] — MVP

Sessions

• SQLite persistence for sessions (rusqlite)
• Session types: SSH, Claude CLI, Agent SDK, Local Shell
• Session CRUD in sidebar
• Session groups/folders
• Remember last layout on restart

Markdown Viewer

• File watcher (notify crate) -> Tauri events -> frontend
• Markdown rendering (marked.js or remark)
• Syntax highlighting (Shiki)
• Open from sidebar or from agent output file references
• Debounce file watcher (200ms)

Milestone: After Phase 4 = MVP ship. Full session management, structured agent panes, terminal panes, markdown viewer.

---

Phase 5: Agent Tree + Polish [status: not_started] — Post-MVP

• Agent tree visualization (SVG, compact horizontal layout)
• Click tree node -> focus agent pane
• Aggregate cost per subtree
• Global status bar (total cost, active agents, uptime)
• Notification system (agent done, error)
• Global keyboard shortcuts
• Settings dialog
• ctx integration (port from v1)

---

Phase 6: Packaging + Distribution [status: not_started] — Post-MVP

• install.sh v2 (check Node.js, install Tauri runtime deps)
• AppImage build (single file, works everywhere)
• .deb package (Debian/Ubuntu)
• GitHub Actions CI for building releases
• Auto-update mechanism (Tauri updater)
• Migrate bterminal.svg icon
• README update

System Requirements

• Node.js 20+ (for Agent SDK sidecar)
• WebKit2GTK 4.1+ (Tauri runtime)
• Linux x86_64 (primary target)