feat(display): add configurable multi-backend display system

feat(websocket): add WebSocket display backend for browser client
merge: effects_plugins
2026-03-15 21:17:16 -07:00 · 2026-03-15 20:54:03 -07:00 · 2026-03-15 19:20:53 -07:00 · 2026-03-15 19:20:47 -07:00 · 2026-03-15 19:20:47 -07:00 · 2026-03-15 19:20:47 -07:00
34 changed files with 3453 additions and 22 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,4 @@ htmlcov/
 .coverage
 .pytest_cache/
 *.egg-info/
+coverage.xml
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -22,13 +22,23 @@ uv sync
 ### Available Commands

 ```bash
-mise run test       # Run tests
-mise run test-v     # Run tests verbose
-mise run test-cov   # Run tests with coverage report
-mise run lint       # Run ruff linter
-mise run lint-fix   # Run ruff with auto-fix
-mise run format     # Run ruff formatter
-mise run ci         # Full CI pipeline (sync + test + coverage)
+mise run test           # Run tests
+mise run test-v         # Run tests verbose
+mise run test-cov       # Run tests with coverage report
+mise run test-browser   # Run e2e browser tests (requires playwright)
+mise run lint           # Run ruff linter
+mise run lint-fix       # Run ruff with auto-fix
+mise run format         # Run ruff formatter
+mise run ci             # Full CI pipeline (sync + test + coverage)
+```
+
+### Runtime Commands
+
+```bash
+mise run run            # Run mainline (terminal)
+mise run run-websocket  # Run with WebSocket display
+mise run run-both       # Run with both terminal and WebSocket
+mise run run-client     # Run both + open browser
 ```

 ## Git Hooks
@@ -108,3 +118,11 @@ The project uses pytest with strict marker enforcement. Test configuration is in
 - **eventbus.py** provides thread-safe event publishing for decoupled communication
 - **controller.py** coordinates ntfy/mic monitoring
 - The render pipeline: fetch → render → effects → scroll → terminal output
+- **Display abstraction** (`engine/display.py`): swap display backends via the Display protocol
+  - `TerminalDisplay` - ANSI terminal output
+  - `WebSocketDisplay` - broadcasts to web clients via WebSocket
+  - `MultiDisplay` - forwards to multiple displays simultaneously
+- **WebSocket display** (`engine/websocket_display.py`): real-time frame broadcasting to web browsers
+  - WebSocket server on port 8765
+  - HTTP server on port 8766 (serves HTML client)
+  - Client at `client/index.html` with ANSI color parsing and fullscreen support
--- a/client/index.html
+++ b/client/index.html
@@ -0,0 +1,366 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Mainline Terminal</title>
+    <style>
+        * {
+            margin: 0;
+            padding: 0;
+            box-sizing: border-box;
+        }
+        body {
+            background: #0a0a0a;
+            color: #ccc;
+            font-family: 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
+            display: flex;
+            flex-direction: column;
+            align-items: center;
+            justify-content: center;
+            min-height: 100vh;
+            padding: 20px;
+        }
+        body.fullscreen {
+            padding: 0;
+        }
+        body.fullscreen #controls {
+            display: none;
+        }
+        #container {
+            position: relative;
+        }
+        canvas {
+            background: #000;
+            border: 1px solid #333;
+            image-rendering: pixelated;
+            image-rendering: crisp-edges;
+        }
+        body.fullscreen canvas {
+            border: none;
+            width: 100vw;
+            height: 100vh;
+            max-width: 100vw;
+            max-height: 100vh;
+        }
+        #controls {
+            display: flex;
+            gap: 10px;
+            margin-top: 10px;
+            align-items: center;
+        }
+        #controls button {
+            background: #333;
+            color: #ccc;
+            border: 1px solid #555;
+            padding: 5px 12px;
+            cursor: pointer;
+            font-family: inherit;
+            font-size: 12px;
+        }
+        #controls button:hover {
+            background: #444;
+        }
+        #controls input {
+            width: 60px;
+            background: #222;
+            color: #ccc;
+            border: 1px solid #444;
+            padding: 4px 8px;
+            font-family: inherit;
+            text-align: center;
+        }
+        #status {
+            margin-top: 10px;
+            font-size: 12px;
+            color: #666;
+        }
+        #status.connected {
+            color: #4f4;
+        }
+        #status.disconnected {
+            color: #f44;
+        }
+    </style>
+</head>
+<body>
+    <div id="container">
+        <canvas id="terminal"></canvas>
+    </div>
+    <div id="controls">
+        <label>Cols: <input type="number" id="cols" value="80" min="20" max="200"></label>
+        <label>Rows: <input type="number" id="rows" value="24" min="10" max="60"></label>
+        <button id="apply">Apply</button>
+        <button id="fullscreen">Fullscreen</button>
+    </div>
+    <div id="status" class="disconnected">Connecting...</div>
+
+    <script>
+        const canvas = document.getElementById('terminal');
+        const ctx = canvas.getContext('2d');
+        const status = document.getElementById('status');
+        const colsInput = document.getElementById('cols');
+        const rowsInput = document.getElementById('rows');
+        const applyBtn = document.getElementById('apply');
+        const fullscreenBtn = document.getElementById('fullscreen');
+
+        const CHAR_WIDTH = 9;
+        const CHAR_HEIGHT = 16;
+
+        const ANSI_COLORS = {
+            0: '#000000', 1: '#cd3131', 2: '#0dbc79', 3: '#e5e510',
+            4: '#2472c8', 5: '#bc3fbc', 6: '#11a8cd', 7: '#e5e5e5',
+            8: '#666666', 9: '#f14c4c', 10: '#23d18b', 11: '#f5f543',
+            12: '#3b8eea', 13: '#d670d6', 14: '#29b8db', 15: '#ffffff',
+        };
+
+        let cols = 80;
+        let rows = 24;
+        let ws = null;
+
+        function resizeCanvas() {
+            canvas.width = cols * CHAR_WIDTH;
+            canvas.height = rows * CHAR_HEIGHT;
+        }
+
+        function parseAnsi(text) {
+            if (!text) return [];
+            
+            const tokens = [];
+            let currentText = '';
+            let fg = '#cccccc';
+            let bg = '#000000';
+            let bold = false;
+            let i = 0;
+            let inEscape = false;
+            let escapeCode = '';
+
+            while (i < text.length) {
+                const char = text[i];
+                
+                if (inEscape) {
+                    if (char >= '0' && char <= '9' || char === ';' || char === '[') {
+                        escapeCode += char;
+                    }
+                    
+                    if (char === 'm') {
+                        const codes = escapeCode.replace('\x1b[', '').split(';');
+                        
+                        for (const code of codes) {
+                            const num = parseInt(code) || 0;
+                            
+                            if (num === 0) {
+                                fg = '#cccccc';
+                                bg = '#000000';
+                                bold = false;
+                            } else if (num === 1) {
+                                bold = true;
+                            } else if (num === 22) {
+                                bold = false;
+                            } else if (num === 39) {
+                                fg = '#cccccc';
+                            } else if (num === 49) {
+                                bg = '#000000';
+                            } else if (num >= 30 && num <= 37) {
+                                fg = ANSI_COLORS[num - 30 + (bold ? 8 : 0)] || '#cccccc';
+                            } else if (num >= 40 && num <= 47) {
+                                bg = ANSI_COLORS[num - 40] || '#000000';
+                            } else if (num >= 90 && num <= 97) {
+                                fg = ANSI_COLORS[num - 90 + 8] || '#cccccc';
+                            } else if (num >= 100 && num <= 107) {
+                                bg = ANSI_COLORS[num - 100 + 8] || '#000000';
+                            } else if (num >= 1 && num <= 256) {
+                                // 256 colors
+                                if (num < 16) {
+                                    fg = ANSI_COLORS[num] || '#cccccc';
+                                } else if (num < 232) {
+                                    const c = num - 16;
+                                    const r = Math.floor(c / 36) * 51;
+                                    const g = Math.floor((c % 36) / 6) * 51;
+                                    const b = (c % 6) * 51;
+                                    fg = `#${r.toString(16).padStart(2,'0')}${g.toString(16).padStart(2,'0')}${b.toString(16).padStart(2,'0')}`;
+                                } else {
+                                    const gray = (num - 232) * 10 + 8;
+                                    fg = `#${gray.toString(16).repeat(2)}`;
+                                }
+                            }
+                        }
+                        
+                        if (currentText) {
+                            tokens.push({ text: currentText, fg, bg, bold });
+                            currentText = '';
+                        }
+                        inEscape = false;
+                        escapeCode = '';
+                    }
+                } else if (char === '\x1b' && text[i + 1] === '[') {
+                    if (currentText) {
+                        tokens.push({ text: currentText, fg, bg, bold });
+                        currentText = '';
+                    }
+                    inEscape = true;
+                    escapeCode = '';
+                    i++;
+                } else {
+                    currentText += char;
+                }
+                i++;
+            }
+
+            if (currentText) {
+                tokens.push({ text: currentText, fg, bg, bold });
+            }
+
+            return tokens;
+        }
+
+        function renderLine(text, x, y, lineHeight) {
+            const tokens = parseAnsi(text);
+            let xOffset = x;
+
+            for (const token of tokens) {
+                if (token.text) {
+                    if (token.bold) {
+                        ctx.font = 'bold 16px monospace';
+                    } else {
+                        ctx.font = '16px monospace';
+                    }
+
+                    const metrics = ctx.measureText(token.text);
+                    
+                    if (token.bg !== '#000000') {
+                        ctx.fillStyle = token.bg;
+                        ctx.fillRect(xOffset, y - 2, metrics.width + 1, lineHeight);
+                    }
+                    
+                    ctx.fillStyle = token.fg;
+                    ctx.fillText(token.text, xOffset, y);
+                    xOffset += metrics.width;
+                }
+            }
+        }
+
+        function connect() {
+            const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+            const wsUrl = `${protocol}//${window.location.hostname}:8765`;
+            
+            ws = new WebSocket(wsUrl);
+
+            ws.onopen = () => {
+                status.textContent = 'Connected';
+                status.className = 'connected';
+                sendSize();
+            };
+
+            ws.onclose = () => {
+                status.textContent = 'Disconnected - Reconnecting...';
+                status.className = 'disconnected';
+                setTimeout(connect, 1000);
+            };
+
+            ws.onerror = () => {
+                status.textContent = 'Connection error';
+                status.className = 'disconnected';
+            };
+
+            ws.onmessage = (event) => {
+                try {
+                    const data = JSON.parse(event.data);
+                    
+                    if (data.type === 'frame') {
+                        cols = data.width || 80;
+                        rows = data.height || 24;
+                        colsInput.value = cols;
+                        rowsInput.value = rows;
+                        resizeCanvas();
+                        render(data.lines || []);
+                    } else if (data.type === 'clear') {
+                        ctx.fillStyle = '#000';
+                        ctx.fillRect(0, 0, canvas.width, canvas.height);
+                    }
+                } catch (e) {
+                    console.error('Failed to parse message:', e);
+                }
+            };
+        }
+
+        function sendSize() {
+            if (ws && ws.readyState === WebSocket.OPEN) {
+                ws.send(JSON.stringify({
+                    type: 'resize',
+                    width: parseInt(colsInput.value),
+                    height: parseInt(rowsInput.value)
+                }));
+            }
+        }
+
+        function render(lines) {
+            ctx.fillStyle = '#000';
+            ctx.fillRect(0, 0, canvas.width, canvas.height);
+
+            ctx.font = '16px monospace';
+            ctx.textBaseline = 'top';
+
+            const lineHeight = CHAR_HEIGHT;
+            const maxLines = Math.min(lines.length, rows);
+
+            for (let i = 0; i < maxLines; i++) {
+                const line = lines[i] || '';
+                renderLine(line, 0, i * lineHeight, lineHeight);
+            }
+        }
+
+        function calculateViewportSize() {
+            const isFullscreen = document.fullscreenElement !== null;
+            const padding = isFullscreen ? 0 : 40;
+            const controlsHeight = isFullscreen ? 0 : 60;
+            const availableWidth = window.innerWidth - padding;
+            const availableHeight = window.innerHeight - controlsHeight;
+            cols = Math.max(20, Math.floor(availableWidth / CHAR_WIDTH));
+            rows = Math.max(10, Math.floor(availableHeight / CHAR_HEIGHT));
+            colsInput.value = cols;
+            rowsInput.value = rows;
+            resizeCanvas();
+            console.log('Fullscreen:', isFullscreen, 'Size:', cols, 'x', rows);
+            sendSize();
+        }
+
+        applyBtn.addEventListener('click', () => {
+            cols = parseInt(colsInput.value);
+            rows = parseInt(rowsInput.value);
+            resizeCanvas();
+            sendSize();
+        });
+
+        fullscreenBtn.addEventListener('click', () => {
+            if (!document.fullscreenElement) {
+                document.body.classList.add('fullscreen');
+                document.documentElement.requestFullscreen().then(() => {
+                    calculateViewportSize();
+                });
+            } else {
+                document.exitFullscreen().then(() => {
+                    calculateViewportSize();
+                });
+            }
+        });
+
+        document.addEventListener('fullscreenchange', () => {
+            if (!document.fullscreenElement) {
+                document.body.classList.remove('fullscreen');
+                calculateViewportSize();
+            }
+        });
+
+        window.addEventListener('resize', () => {
+            if (document.fullscreenElement) {
+                calculateViewportSize();
+            }
+        });
+
+        // Initial setup
+        resizeCanvas();
+        connect();
+    </script>
+</body>
+</html>
--- a/cmdline.py
+++ b/cmdline.py
@@ -0,0 +1,250 @@
+#!/usr/bin/env python3
+"""
+Command-line utility for interacting with mainline via ntfy.
+
+Usage:
+    python cmdline.py                     # Interactive TUI mode
+    python cmdline.py --help              # Show help
+    python cmdline.py /effects list       # Send single command via ntfy
+    python cmdline.py /effects stats      # Get performance stats via ntfy
+    python cmdline.py -w /effects stats   # Watch mode (polls for stats)
+
+The TUI mode provides:
+    - Arrow keys to navigate command history
+    - Tab completion for commands
+    - Auto-refresh for performance stats
+
+C&C works like a serial port:
+    1. Send command to ntfy_cc_topic
+    2. Mainline receives, processes, responds to same topic
+    3. Cmdline polls for response
+"""
+
+import argparse
+import json
+import sys
+import time
+import threading
+import urllib.request
+from pathlib import Path
+
+from engine import config
+from engine.terminal import CLR, CURSOR_OFF, CURSOR_ON, G_DIM, G_HI, RST, W_GHOST
+
+try:
+    CC_CMD_TOPIC = config.NTFY_CC_CMD_TOPIC
+    CC_RESP_TOPIC = config.NTFY_CC_RESP_TOPIC
+except AttributeError:
+    CC_CMD_TOPIC = "https://ntfy.sh/klubhaus_terminal_mainline_cc_cmd/json"
+    CC_RESP_TOPIC = "https://ntfy.sh/klubhaus_terminal_mainline_cc_resp/json"
+
+
+class NtfyResponsePoller:
+    """Polls ntfy for command responses."""
+
+    def __init__(self, cmd_topic: str, resp_topic: str, timeout: float = 10.0):
+        self.cmd_topic = cmd_topic
+        self.resp_topic = resp_topic
+        self.timeout = timeout
+        self._last_id = None
+        self._lock = threading.Lock()
+
+    def _build_url(self) -> str:
+        from urllib.parse import parse_qs, urlencode, urlparse, urlunparse
+
+        parsed = urlparse(self.resp_topic)
+        params = parse_qs(parsed.query, keep_blank_values=True)
+        params["since"] = [self._last_id if self._last_id else "20s"]
+        new_query = urlencode({k: v[0] for k, v in params.items()})
+        return urlunparse(parsed._replace(query=new_query))
+
+    def send_and_wait(self, cmd: str) -> str:
+        """Send command and wait for response."""
+        url = self.cmd_topic.replace("/json", "")
+        data = cmd.encode("utf-8")
+
+        req = urllib.request.Request(
+            url,
+            data=data,
+            headers={
+                "User-Agent": "mainline-cmdline/0.1",
+                "Content-Type": "text/plain",
+            },
+            method="POST",
+        )
+
+        try:
+            urllib.request.urlopen(req, timeout=5)
+        except Exception as e:
+            return f"Error sending command: {e}"
+
+        return self._wait_for_response(cmd)
+
+    def _wait_for_response(self, expected_cmd: str = "") -> str:
+        """Poll for response message."""
+        start = time.time()
+        while time.time() - start < self.timeout:
+            try:
+                url = self._build_url()
+                req = urllib.request.Request(
+                    url, headers={"User-Agent": "mainline-cmdline/0.1"}
+                )
+                with urllib.request.urlopen(req, timeout=10) as resp:
+                    for line in resp:
+                        try:
+                            data = json.loads(line.decode("utf-8", errors="replace"))
+                        except json.JSONDecodeError:
+                            continue
+                        if data.get("event") == "message":
+                            self._last_id = data.get("id")
+                            msg = data.get("message", "")
+                            if msg:
+                                return msg
+            except Exception:
+                pass
+            time.sleep(0.5)
+        return "Timeout waiting for response"
+
+
+AVAILABLE_COMMANDS = """Available commands:
+  /effects list          - List all effects and status
+  /effects <name> on    - Enable an effect
+  /effects <name> off   - Disable an effect
+  /effects <name> intensity <0.0-1.0> - Set effect intensity
+  /effects reorder <name1>,<name2>,... - Reorder pipeline
+  /effects stats        - Show performance statistics
+  /help                 - Show this help
+  /quit                 - Exit
+"""
+
+
+def print_header():
+    w = 60
+    print(CLR, end="")
+    print(CURSOR_OFF, end="")
+    print(f"\033[1;1H", end="")
+    print(f"  \033[1;38;5;231m╔{'═' * (w - 6)}╗\033[0m")
+    print(
+        f"  \033[1;38;5;231m║\033[0m \033[1;38;5;82mMAINLINE\033[0m \033[3;38;5;245mCommand Center\033[0m \033[1;38;5;231m  ║\033[0m"
+    )
+    print(f"  \033[1;38;5;231m╚{'═' * (w - 6)}╝\033[0m")
+    print(f"  \033[2;38;5;37mCMD: {CC_CMD_TOPIC.split('/')[-2]}\033[0m")
+    print(f"  \033[2;38;5;37mRESP: {CC_RESP_TOPIC.split('/')[-2]}\033[0m")
+    print()
+
+
+def print_response(response: str, is_error: bool = False) -> None:
+    """Print response with nice formatting."""
+    print()
+    if is_error:
+        print(f"  \033[1;38;5;196m✗ Error\033[0m")
+        print(f"  \033[38;5;196m{'─' * 40}\033[0m")
+    else:
+        print(f"  \033[1;38;5;82m✓ Response\033[0m")
+        print(f"  \033[38;5;37m{'─' * 40}\033[0m")
+
+    for line in response.split("\n"):
+        print(f"  {line}")
+    print()
+
+
+def interactive_mode():
+    """Interactive TUI for sending commands."""
+    import readline
+
+    print_header()
+    poller = NtfyResponsePoller(CC_CMD_TOPIC, CC_RESP_TOPIC)
+
+    print(f"  \033[38;5;245mType /help for commands, /quit to exit\033[0m")
+    print()
+
+    while True:
+        try:
+            cmd = input(f"  \033[1;38;5;82m❯\033[0m {G_HI}").strip()
+        except (EOFError, KeyboardInterrupt):
+            print()
+            break
+
+        if not cmd:
+            continue
+
+        if cmd.startswith("/"):
+            if cmd == "/quit" or cmd == "/exit":
+                print(f"\n  \033[1;38;5;245mGoodbye!{RST}\n")
+                break
+
+            if cmd == "/help":
+                print(f"\n{AVAILABLE_COMMANDS}\n")
+                continue
+
+            print(f"  \033[38;5;245m⟳ Sending to mainline...{RST}")
+            result = poller.send_and_wait(cmd)
+            print_response(result, is_error=result.startswith("Error"))
+        else:
+            print(f"\n  \033[1;38;5;196m⚠ Commands must start with /{RST}\n")
+
+    print(CURSOR_ON, end="")
+    return 0
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Mainline command-line interface",
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        epilog=AVAILABLE_COMMANDS,
+    )
+    parser.add_argument(
+        "command",
+        nargs="?",
+        default=None,
+        help="Command to send (e.g., /effects list)",
+    )
+    parser.add_argument(
+        "--watch",
+        "-w",
+        action="store_true",
+        help="Watch mode: continuously poll for stats (Ctrl+C to exit)",
+    )
+
+    args = parser.parse_args()
+
+    if args.command is None:
+        return interactive_mode()
+
+    poller = NtfyResponsePoller(CC_CMD_TOPIC, CC_RESP_TOPIC)
+
+    if args.watch and "/effects stats" in args.command:
+        import signal
+
+        def handle_sigterm(*_):
+            print(f"\n  \033[1;38;5;245mStopped watching{RST}")
+            print(CURSOR_ON, end="")
+            sys.exit(0)
+
+        signal.signal(signal.SIGTERM, handle_sigterm)
+
+        print_header()
+        print(f"  \033[38;5;245mWatching /effects stats (Ctrl+C to exit)...{RST}\n")
+        try:
+            while True:
+                result = poller.send_and_wait(args.command)
+                print(f"\033[2J\033[1;1H", end="")
+                print(
+                    f"  \033[1;38;5;82m❯\033[0m Performance Stats - \033[1;38;5;245m{time.strftime('%H:%M:%S')}{RST}"
+                )
+                print(f"  \033[38;5;37m{'─' * 44}{RST}")
+                for line in result.split("\n"):
+                    print(f"  {line}")
+                time.sleep(2)
+        except KeyboardInterrupt:
+            print(f"\n  \033[1;38;5;245mStopped watching{RST}")
+            return 0
+        return 0
+
+    result = poller.send_and_wait(args.command)
+    print(result)
+    return 0
+
+
+if __name__ == "__main__":
+    main()
--- a/effects_plugins/init.py
+++ b/effects_plugins/init.py
@@ -0,0 +1,35 @@
+from pathlib import Path
+
+PLUGIN_DIR = Path(__file__).parent
+
+
+def discover_plugins():
+    from engine.effects.registry import get_registry
+
+    registry = get_registry()
+    imported = {}
+
+    for file_path in PLUGIN_DIR.glob("*.py"):
+        if file_path.name.startswith("_"):
+            continue
+        module_name = file_path.stem
+        if module_name in ("base", "types"):
+            continue
+
+        try:
+            module = __import__(f"effects_plugins.{module_name}", fromlist=[""])
+            for attr_name in dir(module):
+                attr = getattr(module, attr_name)
+                if (
+                    isinstance(attr, type)
+                    and hasattr(attr, "name")
+                    and hasattr(attr, "process")
+                    and attr_name.endswith("Effect")
+                ):
+                    plugin = attr()
+                    registry.register(plugin)
+                    imported[plugin.name] = plugin
+        except Exception:
+            pass
+
+    return imported
--- a/effects_plugins/fade.py
+++ b/effects_plugins/fade.py
@@ -0,0 +1,58 @@
+import random
+
+from engine.effects.types import EffectConfig, EffectContext, EffectPlugin
+
+
+class FadeEffect:
+    name = "fade"
+    config = EffectConfig(enabled=True, intensity=1.0)
+
+    def process(self, buf: list[str], ctx: EffectContext) -> list[str]:
+        if not ctx.ticker_height:
+            return buf
+        result = list(buf)
+        intensity = self.config.intensity
+
+        top_zone = max(1, int(ctx.ticker_height * 0.25))
+        bot_zone = max(1, int(ctx.ticker_height * 0.10))
+
+        for r in range(len(result)):
+            if r >= ctx.ticker_height:
+                continue
+            top_f = min(1.0, r / top_zone) if top_zone > 0 else 1.0
+            bot_f = (
+                min(1.0, (ctx.ticker_height - 1 - r) / bot_zone)
+                if bot_zone > 0
+                else 1.0
+            )
+            row_fade = min(top_f, bot_f) * intensity
+
+            if row_fade < 1.0 and result[r].strip():
+                result[r] = self._fade_line(result[r], row_fade)
+
+        return result
+
+    def _fade_line(self, s: str, fade: float) -> str:
+        if fade >= 1.0:
+            return s
+        if fade <= 0.0:
+            return ""
+        result = []
+        i = 0
+        while i < len(s):
+            if s[i] == "\033" and i + 1 < len(s) and s[i + 1] == "[":
+                j = i + 2
+                while j < len(s) and not s[j].isalpha():
+                    j += 1
+                result.append(s[i : j + 1])
+                i = j + 1
+            elif s[i] == " ":
+                result.append(" ")
+                i += 1
+            else:
+                result.append(s[i] if random.random() < fade else " ")
+                i += 1
+        return "".join(result)
+
+    def configure(self, cfg: EffectConfig) -> None:
+        self.config = cfg
--- a/effects_plugins/firehose.py
+++ b/effects_plugins/firehose.py
@@ -0,0 +1,72 @@
+import random
+from datetime import datetime
+
+from engine import config
+from engine.effects.types import EffectConfig, EffectContext, EffectPlugin
+from engine.sources import FEEDS, POETRY_SOURCES
+from engine.terminal import C_DIM, G_DIM, G_LO, RST, W_GHOST
+
+
+class FirehoseEffect:
+    name = "firehose"
+    config = EffectConfig(enabled=True, intensity=1.0)
+
+    def process(self, buf: list[str], ctx: EffectContext) -> list[str]:
+        firehose_h = config.FIREHOSE_H if config.FIREHOSE else 0
+        if firehose_h <= 0 or not ctx.items:
+            return buf
+
+        result = list(buf)
+        intensity = self.config.intensity
+        h = ctx.terminal_height
+
+        for fr in range(firehose_h):
+            scr_row = h - firehose_h + fr + 1
+            fline = self._firehose_line(ctx.items, ctx.terminal_width, intensity)
+            result.append(f"\033[{scr_row};1H{fline}\033[K")
+        return result
+
+    def _firehose_line(self, items: list, w: int, intensity: float) -> str:
+        r = random.random()
+        if r < 0.35 * intensity:
+            title, src, ts = random.choice(items)
+            text = title[: w - 1]
+            color = random.choice([G_LO, G_DIM, W_GHOST, C_DIM])
+            return f"{color}{text}{RST}"
+        elif r < 0.55 * intensity:
+            d = random.choice([0.45, 0.55, 0.65, 0.75])
+            return "".join(
+                f"{random.choice([G_LO, G_DIM, C_DIM, W_GHOST])}"
+                f"{random.choice(config.GLITCH + config.KATA)}{RST}"
+                if random.random() < d
+                else " "
+                for _ in range(w)
+            )
+        elif r < 0.78 * intensity:
+            sources = FEEDS if config.MODE == "news" else POETRY_SOURCES
+            src = random.choice(list(sources.keys()))
+            msgs = [
+                f"  SIGNAL :: {src} :: {datetime.now().strftime('%H:%M:%S.%f')[:-3]}",
+                f"  ░░ FEED ACTIVE :: {src}",
+                f"  >> DECODE 0x{random.randint(0x1000, 0xFFFF):04X} :: {src[:24]}",
+                f"  ▒▒ ACQUIRE :: {random.choice(['TCP', 'UDP', 'RSS', 'ATOM', 'XML'])} :: {src}",
+                f"  {''.join(random.choice(config.KATA) for _ in range(3))} STRM "
+                f"{random.randint(0, 255):02X}:{random.randint(0, 255):02X}",
+            ]
+            text = random.choice(msgs)[: w - 1]
+            color = random.choice([G_LO, G_DIM, W_GHOST])
+            return f"{color}{text}{RST}"
+        else:
+            title, _, _ = random.choice(items)
+            start = random.randint(0, max(0, len(title) - 20))
+            frag = title[start : start + random.randint(10, 35)]
+            pad = random.randint(0, max(0, w - len(frag) - 8))
+            gp = "".join(
+                random.choice(config.GLITCH) for _ in range(random.randint(1, 3))
+            )
+            text = (" " * pad + gp + " " + frag)[: w - 1]
+            color = random.choice([G_LO, C_DIM, W_GHOST])
+            return f"{color}{text}{RST}"
+
+    def configure(self, cfg: EffectConfig) -> None:
+        self.config = cfg
--- a/effects_plugins/glitch.py
+++ b/effects_plugins/glitch.py
@@ -0,0 +1,37 @@
+import random
+
+from engine import config
+from engine.effects.types import EffectConfig, EffectContext, EffectPlugin
+from engine.terminal import C_DIM, DIM, G_DIM, G_LO, RST
+
+
+class GlitchEffect:
+    name = "glitch"
+    config = EffectConfig(enabled=True, intensity=1.0)
+
+    def process(self, buf: list[str], ctx: EffectContext) -> list[str]:
+        if not buf:
+            return buf
+        result = list(buf)
+        intensity = self.config.intensity
+
+        glitch_prob = 0.32 + min(0.9, ctx.mic_excess * 0.16)
+        glitch_prob = glitch_prob * intensity
+        n_hits = 4 + int(ctx.mic_excess / 2)
+        n_hits = int(n_hits * intensity)
+
+        if random.random() < glitch_prob:
+            for _ in range(min(n_hits, len(result))):
+                gi = random.randint(0, len(result) - 1)
+                scr_row = gi + 1
+                result[gi] = f"\033[{scr_row};1H{self._glitch_bar(ctx.terminal_width)}"
+        return result
+
+    def _glitch_bar(self, w: int) -> str:
+        c = random.choice(["░", "▒", "─", "\xc2"])
+        n = random.randint(3, w // 2)
+        o = random.randint(0, w - n)
+        return " " * o + f"{G_LO}{DIM}" + c * n + RST
+
+    def configure(self, cfg: EffectConfig) -> None:
+        self.config = cfg
--- a/effects_plugins/noise.py
+++ b/effects_plugins/noise.py
@@ -0,0 +1,36 @@
+import random
+
+from engine import config
+from engine.effects.types import EffectConfig, EffectContext, EffectPlugin
+from engine.terminal import C_DIM, G_DIM, G_LO, RST, W_GHOST
+
+
+class NoiseEffect:
+    name = "noise"
+    config = EffectConfig(enabled=True, intensity=0.15)
+
+    def process(self, buf: list[str], ctx: EffectContext) -> list[str]:
+        if not ctx.ticker_height:
+            return buf
+        result = list(buf)
+        intensity = self.config.intensity
+        probability = intensity * 0.15
+
+        for r in range(len(result)):
+            cy = ctx.scroll_cam + r
+            if random.random() < probability:
+                result[r] = self._generate_noise(ctx.terminal_width, cy)
+        return result
+
+    def _generate_noise(self, w: int, cy: int) -> str:
+        d = random.choice([0.15, 0.25, 0.35, 0.12])
+        return "".join(
+            f"{random.choice([G_LO, G_DIM, C_DIM, W_GHOST])}"
+            f"{random.choice(config.GLITCH + config.KATA)}{RST}"
+            if random.random() < d
+            else " "
+            for _ in range(w)
+        )
+
+    def configure(self, cfg: EffectConfig) -> None:
+        self.config = cfg
--- a/engine/app.py
+++ b/engine/app.py
@@ -29,6 +29,30 @@ from engine.terminal import (
    slow_print,
    tw,
 )
+from engine.websocket_display import WebSocketDisplay
+
+
+def _get_display():
+    """Get the appropriate display(s) based on config."""
+    from engine.display import MultiDisplay, TerminalDisplay
+
+    displays = []
+
+    if config.DISPLAY in ("terminal", "both"):
+        displays.append(TerminalDisplay())
+
+    if config.DISPLAY in ("websocket", "both") or config.WEBSOCKET:
+        ws = WebSocketDisplay(host="0.0.0.0", port=config.WEBSOCKET_PORT)
+        ws.start_server()
+        ws.start_http_server()
+        displays.append(ws)
+
+    if not displays:
+        return None
+    if len(displays) == 1:
+        return displays[0]
+    return MultiDisplay(displays)
+

 TITLE = [
    "  ███╗   ███╗ █████╗ ██╗███╗   ██╗██╗     ██╗███╗   ██╗███████╗",
@@ -343,7 +367,10 @@ def main():
    print()
    time.sleep(0.4)

-    stream(items, ntfy, mic)
+    display = _get_display()
+    stream(items, ntfy, mic, display)
+    if display:
+        display.cleanup()

    print()
    print(f"  {W_GHOST}{'─' * (tw() - 4)}{RST}")
--- a/engine/config.py
+++ b/engine/config.py
@@ -127,6 +127,10 @@ class Config:

    script_fonts: dict[str, str] = field(default_factory=_get_platform_font_paths)

+    display: str = "terminal"
+    websocket: bool = False
+    websocket_port: int = 8765
+
    @classmethod
    def from_args(cls, argv: list[str] | None = None) -> "Config":
        """Create Config from CLI arguments (or custom argv for testing)."""
@@ -164,6 +168,9 @@ class Config:
            glitch_glyphs="░▒▓█▌▐╌╍╎╏┃┆┇┊┋",
            kata_glyphs="ﾊﾐﾋｰｳｼﾅﾓﾆｻﾜﾂｵﾘｱﾎﾃﾏｹﾒｴｶｷﾑﾕﾗｾﾈｽﾀﾇﾍ",
            script_fonts=_get_platform_font_paths(),
+            display=_arg_value("--display", argv) or "terminal",
+            websocket="--websocket" in argv,
+            websocket_port=_arg_int("--websocket-port", 8765, argv),
        )


@@ -223,6 +230,11 @@ GRAD_SPEED = 0.08  # gradient traversal speed (cycles/sec, ~12s full sweep)
 GLITCH = "░▒▓█▌▐╌╍╎╏┃┆┇┊┋"
 KATA = "ﾊﾐﾋｰｳｼﾅﾓﾆｻﾜﾂｵﾘｱﾎﾃﾏｹﾒｴｶｷﾑﾕﾗｾﾈｽﾀﾇﾍ"

+# ─── WEBSOCKET ─────────────────────────────────────────────
+DISPLAY = _arg_value("--display", sys.argv) or "terminal"
+WEBSOCKET = "--websocket" in sys.argv
+WEBSOCKET_PORT = _arg_int("--websocket-port", 8765)
+

 def set_font_selection(font_path=None, font_index=None):
    """Set runtime primary font selection."""
--- a/engine/controller.py
+++ b/engine/controller.py
@@ -8,6 +8,17 @@ from engine.events import EventType, StreamEvent
 from engine.mic import MicMonitor
 from engine.ntfy import NtfyPoller
 from engine.scroll import stream
+from engine.websocket_display import WebSocketDisplay
+
+
+def _get_display(config: Config):
+    """Get the appropriate display based on config."""
+    if config.websocket:
+        ws = WebSocketDisplay(host="0.0.0.0", port=config.websocket_port)
+        ws.start_server()
+        ws.start_http_server()
+        return ws
+    return None


 class StreamController:
@@ -51,7 +62,10 @@ class StreamController:
                ),
            )

-        stream(items, self.ntfy, self.mic)
+        display = _get_display(self.config)
+        stream(items, self.ntfy, self.mic, display)
+        if display:
+            display.cleanup()

        if self.event_bus:
            self.event_bus.publish(
--- a/engine/display.py
+++ b/engine/display.py
@@ -0,0 +1,129 @@
+"""
+Display output abstraction - allows swapping output backends.
+
+Protocol:
+    - init(width, height): Initialize display with terminal dimensions
+    - show(buffer): Render buffer (list of strings) to display
+    - clear(): Clear the display
+    - cleanup(): Shutdown display
+"""
+
+import time
+from typing import Protocol
+
+
+class Display(Protocol):
+    """Protocol for display backends."""
+
+    def init(self, width: int, height: int) -> None:
+        """Initialize display with dimensions."""
+        ...
+
+    def show(self, buffer: list[str]) -> None:
+        """Show buffer on display."""
+        ...
+
+    def clear(self) -> None:
+        """Clear display."""
+        ...
+
+    def cleanup(self) -> None:
+        """Shutdown display."""
+        ...
+
+
+def get_monitor():
+    """Get the performance monitor."""
+    try:
+        from engine.effects.performance import get_monitor as _get_monitor
+
+        return _get_monitor()
+    except Exception:
+        return None
+
+
+class TerminalDisplay:
+    """ANSI terminal display backend."""
+
+    def __init__(self):
+        self.width = 80
+        self.height = 24
+
+    def init(self, width: int, height: int) -> None:
+        from engine.terminal import CURSOR_OFF
+
+        self.width = width
+        self.height = height
+        print(CURSOR_OFF, end="", flush=True)
+
+    def show(self, buffer: list[str]) -> None:
+        import sys
+
+        t0 = time.perf_counter()
+        sys.stdout.buffer.write("".join(buffer).encode())
+        sys.stdout.flush()
+        elapsed_ms = (time.perf_counter() - t0) * 1000
+
+        monitor = get_monitor()
+        if monitor:
+            chars_in = sum(len(line) for line in buffer)
+            monitor.record_effect("terminal_display", elapsed_ms, chars_in, chars_in)
+
+    def clear(self) -> None:
+        from engine.terminal import CLR
+
+        print(CLR, end="", flush=True)
+
+    def cleanup(self) -> None:
+        from engine.terminal import CURSOR_ON
+
+        print(CURSOR_ON, end="", flush=True)
+
+
+class NullDisplay:
+    """Headless/null display - discards all output."""
+
+    def init(self, width: int, height: int) -> None:
+        self.width = width
+        self.height = height
+
+    def show(self, buffer: list[str]) -> None:
+        monitor = get_monitor()
+        if monitor:
+            t0 = time.perf_counter()
+            chars_in = sum(len(line) for line in buffer)
+            elapsed_ms = (time.perf_counter() - t0) * 1000
+            monitor.record_effect("null_display", elapsed_ms, chars_in, chars_in)
+
+    def clear(self) -> None:
+        pass
+
+    def cleanup(self) -> None:
+        pass
+
+
+class MultiDisplay:
+    """Display that forwards to multiple displays."""
+
+    def __init__(self, displays: list[Display]):
+        self.displays = displays
+        self.width = 80
+        self.height = 24
+
+    def init(self, width: int, height: int) -> None:
+        self.width = width
+        self.height = height
+        for d in self.displays:
+            d.init(width, height)
+
+    def show(self, buffer: list[str]) -> None:
+        for d in self.displays:
+            d.show(buffer)
+
+    def clear(self) -> None:
+        for d in self.displays:
+            d.clear()
+
+    def cleanup(self) -> None:
+        for d in self.displays:
+            d.cleanup()
--- a/engine/effects/init.py
+++ b/engine/effects/init.py
@@ -0,0 +1,42 @@
+from engine.effects.chain import EffectChain
+from engine.effects.controller import handle_effects_command, show_effects_menu
+from engine.effects.legacy import (
+    fade_line,
+    firehose_line,
+    glitch_bar,
+    next_headline,
+    noise,
+    vis_trunc,
+)
+from engine.effects.performance import PerformanceMonitor, get_monitor, set_monitor
+from engine.effects.registry import EffectRegistry, get_registry, set_registry
+from engine.effects.types import EffectConfig, EffectContext, PipelineConfig
+
+
+def get_effect_chain():
+    from engine.layers import get_effect_chain as _chain
+
+    return _chain()
+
+
+__all__ = [
+    "EffectChain",
+    "EffectRegistry",
+    "EffectConfig",
+    "EffectContext",
+    "PipelineConfig",
+    "get_registry",
+    "set_registry",
+    "get_effect_chain",
+    "get_monitor",
+    "set_monitor",
+    "PerformanceMonitor",
+    "handle_effects_command",
+    "show_effects_menu",
+    "fade_line",
+    "firehose_line",
+    "glitch_bar",
+    "noise",
+    "next_headline",
+    "vis_trunc",
+]
--- a/engine/effects/chain.py
+++ b/engine/effects/chain.py
@@ -0,0 +1,71 @@
+import time
+
+from engine.effects.performance import PerformanceMonitor, get_monitor
+from engine.effects.registry import EffectRegistry
+from engine.effects.types import EffectContext
+
+
+class EffectChain:
+    def __init__(
+        self, registry: EffectRegistry, monitor: PerformanceMonitor | None = None
+    ):
+        self._registry = registry
+        self._order: list[str] = []
+        self._monitor = monitor
+
+    def _get_monitor(self) -> PerformanceMonitor:
+        if self._monitor is not None:
+            return self._monitor
+        return get_monitor()
+
+    def set_order(self, names: list[str]) -> None:
+        self._order = list(names)
+
+    def get_order(self) -> list[str]:
+        return self._order.copy()
+
+    def add_effect(self, name: str, position: int | None = None) -> bool:
+        if name not in self._registry.list_all():
+            return False
+        if position is None:
+            self._order.append(name)
+        else:
+            self._order.insert(position, name)
+        return True
+
+    def remove_effect(self, name: str) -> bool:
+        if name in self._order:
+            self._order.remove(name)
+            return True
+        return False
+
+    def reorder(self, new_order: list[str]) -> bool:
+        all_plugins = set(self._registry.list_all().keys())
+        if not all(name in all_plugins for name in new_order):
+            return False
+        self._order = list(new_order)
+        return True
+
+    def process(self, buf: list[str], ctx: EffectContext) -> list[str]:
+        monitor = self._get_monitor()
+        frame_number = ctx.frame_number
+        monitor.start_frame(frame_number)
+
+        frame_start = time.perf_counter()
+        result = list(buf)
+        for name in self._order:
+            plugin = self._registry.get(name)
+            if plugin and plugin.config.enabled:
+                chars_in = sum(len(line) for line in result)
+                effect_start = time.perf_counter()
+                try:
+                    result = plugin.process(result, ctx)
+                except Exception:
+                    plugin.config.enabled = False
+                elapsed = time.perf_counter() - effect_start
+                chars_out = sum(len(line) for line in result)
+                monitor.record_effect(name, elapsed * 1000, chars_in, chars_out)
+
+        total_elapsed = time.perf_counter() - frame_start
+        monitor.end_frame(frame_number, total_elapsed * 1000)
+        return result
--- a/engine/effects/controller.py
+++ b/engine/effects/controller.py
@@ -0,0 +1,144 @@
+from engine.effects.performance import get_monitor
+from engine.effects.registry import get_registry
+
+_effect_chain_ref = None
+
+
+def _get_effect_chain():
+    global _effect_chain_ref
+    if _effect_chain_ref is not None:
+        return _effect_chain_ref
+    try:
+        from engine.layers import get_effect_chain as _chain
+
+        return _chain()
+    except Exception:
+        return None
+
+
+def set_effect_chain_ref(chain) -> None:
+    global _effect_chain_ref
+    _effect_chain_ref = chain
+
+
+def handle_effects_command(cmd: str) -> str:
+    """Handle /effects command from NTFY message.
+
+    Commands:
+        /effects list - list all effects and their status
+        /effects <name> on - enable an effect
+        /effects <name> off - disable an effect
+        /effects <name> intensity <0.0-1.0> - set intensity
+        /effects reorder <name1>,<name2>,... - reorder pipeline
+        /effects stats - show performance statistics
+    """
+    parts = cmd.strip().split()
+    if not parts or parts[0] != "/effects":
+        return "Unknown command"
+
+    registry = get_registry()
+    chain = _get_effect_chain()
+
+    if len(parts) == 1 or parts[1] == "list":
+        result = ["Effects:"]
+        for name, plugin in registry.list_all().items():
+            status = "ON" if plugin.config.enabled else "OFF"
+            intensity = plugin.config.intensity
+            result.append(f"  {name}: {status} (intensity={intensity})")
+        if chain:
+            result.append(f"Order: {chain.get_order()}")
+        return "\n".join(result)
+
+    if parts[1] == "stats":
+        return _format_stats()
+
+    if parts[1] == "reorder" and len(parts) >= 3:
+        new_order = parts[2].split(",")
+        if chain and chain.reorder(new_order):
+            return f"Reordered pipeline: {new_order}"
+        return "Failed to reorder pipeline"
+
+    if len(parts) < 3:
+        return "Usage: /effects <name> on|off|intensity <value>"
+
+    effect_name = parts[1]
+    action = parts[2]
+
+    if effect_name not in registry.list_all():
+        return f"Unknown effect: {effect_name}"
+
+    if action == "on":
+        registry.enable(effect_name)
+        return f"Enabled: {effect_name}"
+
+    if action == "off":
+        registry.disable(effect_name)
+        return f"Disabled: {effect_name}"
+
+    if action == "intensity" and len(parts) >= 4:
+        try:
+            value = float(parts[3])
+            if not 0.0 <= value <= 1.0:
+                return "Intensity must be between 0.0 and 1.0"
+            plugin = registry.get(effect_name)
+            if plugin:
+                plugin.config.intensity = value
+                return f"Set {effect_name} intensity to {value}"
+        except ValueError:
+            return "Invalid intensity value"
+
+    return f"Unknown action: {action}"
+
+
+def _format_stats() -> str:
+    monitor = get_monitor()
+    stats = monitor.get_stats()
+
+    if "error" in stats:
+        return stats["error"]
+
+    lines = ["Performance Stats:"]
+
+    pipeline = stats["pipeline"]
+    lines.append(
+        f"  Pipeline: avg={pipeline['avg_ms']:.2f}ms min={pipeline['min_ms']:.2f}ms max={pipeline['max_ms']:.2f}ms (over {stats['frame_count']} frames)"
+    )
+
+    if stats["effects"]:
+        lines.append("  Per-effect (avg ms):")
+        for name, effect_stats in stats["effects"].items():
+            lines.append(
+                f"    {name}: avg={effect_stats['avg_ms']:.2f}ms min={effect_stats['min_ms']:.2f}ms max={effect_stats['max_ms']:.2f}ms"
+            )
+
+    return "\n".join(lines)
+
+
+def show_effects_menu() -> str:
+    """Generate effects menu text for display."""
+    registry = get_registry()
+    chain = _get_effect_chain()
+
+    lines = [
+        "\033[1;38;5;231m=== EFFECTS MENU ===\033[0m",
+        "",
+        "Effects:",
+    ]
+
+    for name, plugin in registry.list_all().items():
+        status = "ON" if plugin.config.enabled else "OFF"
+        intensity = plugin.config.intensity
+        lines.append(f"  [{status:3}] {name}: intensity={intensity:.2f}")
+
+    if chain:
+        lines.append("")
+        lines.append(f"Pipeline order: {' -> '.join(chain.get_order())}")
+
+    lines.append("")
+    lines.append("Controls:")
+    lines.append("  /effects <name> on|off")
+    lines.append("  /effects <name> intensity <0.0-1.0>")
+    lines.append("  /effects reorder name1,name2,...")
+    lines.append("")
+
+    return "\n".join(lines)
--- a/engine/effects/legacy.py
+++ b/engine/effects/legacy.py
--- a/engine/effects/performance.py
+++ b/engine/effects/performance.py
@@ -0,0 +1,103 @@
+from collections import deque
+from dataclasses import dataclass
+
+
+@dataclass
+class EffectTiming:
+    name: str
+    duration_ms: float
+    buffer_chars_in: int
+    buffer_chars_out: int
+
+
+@dataclass
+class FrameTiming:
+    frame_number: int
+    total_ms: float
+    effects: list[EffectTiming]
+
+
+class PerformanceMonitor:
+    """Collects and stores performance metrics for effect pipeline."""
+
+    def __init__(self, max_frames: int = 60):
+        self._max_frames = max_frames
+        self._frames: deque[FrameTiming] = deque(maxlen=max_frames)
+        self._current_frame: list[EffectTiming] = []
+
+    def start_frame(self, frame_number: int) -> None:
+        self._current_frame = []
+
+    def record_effect(
+        self, name: str, duration_ms: float, chars_in: int, chars_out: int
+    ) -> None:
+        self._current_frame.append(
+            EffectTiming(
+                name=name,
+                duration_ms=duration_ms,
+                buffer_chars_in=chars_in,
+                buffer_chars_out=chars_out,
+            )
+        )
+
+    def end_frame(self, frame_number: int, total_ms: float) -> None:
+        self._frames.append(
+            FrameTiming(
+                frame_number=frame_number,
+                total_ms=total_ms,
+                effects=self._current_frame,
+            )
+        )
+
+    def get_stats(self) -> dict:
+        if not self._frames:
+            return {"error": "No timing data available"}
+
+        total_times = [f.total_ms for f in self._frames]
+        avg_total = sum(total_times) / len(total_times)
+        min_total = min(total_times)
+        max_total = max(total_times)
+
+        effect_stats: dict[str, dict] = {}
+        for frame in self._frames:
+            for effect in frame.effects:
+                if effect.name not in effect_stats:
+                    effect_stats[effect.name] = {"times": [], "total_chars": 0}
+                effect_stats[effect.name]["times"].append(effect.duration_ms)
+                effect_stats[effect.name]["total_chars"] += effect.buffer_chars_out
+
+        for name, stats in effect_stats.items():
+            times = stats["times"]
+            stats["avg_ms"] = sum(times) / len(times)
+            stats["min_ms"] = min(times)
+            stats["max_ms"] = max(times)
+            del stats["times"]
+
+        return {
+            "frame_count": len(self._frames),
+            "pipeline": {
+                "avg_ms": avg_total,
+                "min_ms": min_total,
+                "max_ms": max_total,
+            },
+            "effects": effect_stats,
+        }
+
+    def reset(self) -> None:
+        self._frames.clear()
+        self._current_frame = []
+
+
+_monitor: PerformanceMonitor | None = None
+
+
+def get_monitor() -> PerformanceMonitor:
+    global _monitor
+    if _monitor is None:
+        _monitor = PerformanceMonitor()
+    return _monitor
+
+
+def set_monitor(monitor: PerformanceMonitor) -> None:
+    global _monitor
+    _monitor = monitor
--- a/engine/effects/registry.py
+++ b/engine/effects/registry.py
@@ -0,0 +1,59 @@
+from engine.effects.types import EffectConfig, EffectPlugin
+
+
+class EffectRegistry:
+    def __init__(self):
+        self._plugins: dict[str, EffectPlugin] = {}
+        self._discovered: bool = False
+
+    def register(self, plugin: EffectPlugin) -> None:
+        self._plugins[plugin.name] = plugin
+
+    def get(self, name: str) -> EffectPlugin | None:
+        return self._plugins.get(name)
+
+    def list_all(self) -> dict[str, EffectPlugin]:
+        return self._plugins.copy()
+
+    def list_enabled(self) -> list[EffectPlugin]:
+        return [p for p in self._plugins.values() if p.config.enabled]
+
+    def enable(self, name: str) -> bool:
+        plugin = self._plugins.get(name)
+        if plugin:
+            plugin.config.enabled = True
+            return True
+        return False
+
+    def disable(self, name: str) -> bool:
+        plugin = self._plugins.get(name)
+        if plugin:
+            plugin.config.enabled = False
+            return True
+        return False
+
+    def configure(self, name: str, config: EffectConfig) -> bool:
+        plugin = self._plugins.get(name)
+        if plugin:
+            plugin.configure(config)
+            return True
+        return False
+
+    def is_enabled(self, name: str) -> bool:
+        plugin = self._plugins.get(name)
+        return plugin.config.enabled if plugin else False
+
+
+_registry: EffectRegistry | None = None
+
+
+def get_registry() -> EffectRegistry:
+    global _registry
+    if _registry is None:
+        _registry = EffectRegistry()
+    return _registry
+
+
+def set_registry(registry: EffectRegistry) -> None:
+    global _registry
+    _registry = registry
--- a/engine/effects/types.py
+++ b/engine/effects/types.py
@@ -0,0 +1,39 @@
+from dataclasses import dataclass, field
+from typing import Any
+
+
+@dataclass
+class EffectContext:
+    terminal_width: int
+    terminal_height: int
+    scroll_cam: int
+    ticker_height: int
+    mic_excess: float
+    grad_offset: float
+    frame_number: int
+    has_message: bool
+    items: list = field(default_factory=list)
+
+
+@dataclass
+class EffectConfig:
+    enabled: bool = True
+    intensity: float = 1.0
+    params: dict[str, Any] = field(default_factory=dict)
+
+
+class EffectPlugin:
+    name: str
+    config: EffectConfig
+
+    def process(self, buf: list[str], ctx: EffectContext) -> list[str]:
+        raise NotImplementedError
+
+    def configure(self, config: EffectConfig) -> None:
+        raise NotImplementedError
+
+
+@dataclass
+class PipelineConfig:
+    order: list[str] = field(default_factory=list)
+    effects: dict[str, EffectConfig] = field(default_factory=dict)
--- a/engine/layers.py
+++ b/engine/layers.py
@@ -10,6 +10,8 @@ from datetime import datetime

 from engine import config
 from engine.effects import (
+    EffectChain,
+    EffectContext,
    fade_line,
    firehose_line,
    glitch_bar,
@@ -199,3 +201,60 @@ def render_firehose(items: list, w: int, fh: int, h: int) -> list[str]:
            fline = firehose_line(items, w)
            buf.append(f"\033[{scr_row};1H{fline}\033[K")
    return buf
+
+
+_effect_chain = None
+
+
+def init_effects() -> None:
+    """Initialize effect plugins and chain."""
+    global _effect_chain
+    from engine.effects import EffectChain, get_registry
+
+    registry = get_registry()
+
+    import effects_plugins
+
+    effects_plugins.discover_plugins()
+
+    chain = EffectChain(registry)
+    chain.set_order(["noise", "fade", "glitch", "firehose"])
+    _effect_chain = chain
+
+
+def process_effects(
+    buf: list[str],
+    w: int,
+    h: int,
+    scroll_cam: int,
+    ticker_h: int,
+    mic_excess: float,
+    grad_offset: float,
+    frame_number: int,
+    has_message: bool,
+    items: list,
+) -> list[str]:
+    """Process buffer through effect chain."""
+    if _effect_chain is None:
+        init_effects()
+
+    ctx = EffectContext(
+        terminal_width=w,
+        terminal_height=h,
+        scroll_cam=scroll_cam,
+        ticker_height=ticker_h,
+        mic_excess=mic_excess,
+        grad_offset=grad_offset,
+        frame_number=frame_number,
+        has_message=has_message,
+        items=items,
+    )
+    return _effect_chain.process(buf, ctx)
+
+
+def get_effect_chain() -> EffectChain | None:
+    """Get the effect chain instance."""
+    global _effect_chain
+    if _effect_chain is None:
+        init_effects()
+    return _effect_chain
--- a/engine/scroll.py
+++ b/engine/scroll.py
@@ -4,33 +4,42 @@ Orchestrates viewport, frame timing, and layers.
 """

 import random
-import sys
 import time

 from engine import config
+from engine.display import (
+    Display,
+    TerminalDisplay,
+)
+from engine.display import (
+    get_monitor as _get_display_monitor,
+)
 from engine.frame import calculate_scroll_step
 from engine.layers import (
    apply_glitch,
+    process_effects,
    render_firehose,
    render_message_overlay,
    render_ticker_zone,
 )
-from engine.terminal import CLR
 from engine.viewport import th, tw

+USE_EFFECT_CHAIN = True

-def stream(items, ntfy_poller, mic_monitor):
+
+def stream(items, ntfy_poller, mic_monitor, display: Display | None = None):
    """Main render loop with four layers: message, ticker, scroll motion, firehose."""
+    if display is None:
+        display = TerminalDisplay()
    random.shuffle(items)
    pool = list(items)
    seen = set()
    queued = 0

    time.sleep(0.5)
-    sys.stdout.write(CLR)
-    sys.stdout.flush()
-
    w, h = tw(), th()
+    display.init(w, h)
+    display.clear()
    fh = config.FIREHOSE_H if config.FIREHOSE else 0
    ticker_view_h = h - fh
    GAP = 3
@@ -42,6 +51,7 @@ def stream(items, ntfy_poller, mic_monitor):
    noise_cache = {}
    scroll_motion_accum = 0.0
    msg_cache = (None, None)
+    frame_number = 0

    while True:
        if queued >= config.HEADLINE_LIMIT and not active:
@@ -93,19 +103,39 @@ def stream(items, ntfy_poller, mic_monitor):
        buf.extend(ticker_buf)

        mic_excess = mic_monitor.excess
-        buf = apply_glitch(buf, ticker_buf_start, mic_excess, w)
+        render_start = time.perf_counter()

-        firehose_buf = render_firehose(items, w, fh, h)
-        buf.extend(firehose_buf)
+        if USE_EFFECT_CHAIN:
+            buf = process_effects(
+                buf,
+                w,
+                h,
+                scroll_cam,
+                ticker_h,
+                mic_excess,
+                grad_offset,
+                frame_number,
+                msg is not None,
+                items,
+            )
+        else:
+            buf = apply_glitch(buf, ticker_buf_start, mic_excess, w)
+            firehose_buf = render_firehose(items, w, fh, h)
+            buf.extend(firehose_buf)

        if msg_overlay:
            buf.extend(msg_overlay)

-        sys.stdout.buffer.write("".join(buf).encode())
-        sys.stdout.flush()
+        render_elapsed = (time.perf_counter() - render_start) * 1000
+        monitor = _get_display_monitor()
+        if monitor:
+            chars = sum(len(line) for line in buf)
+            monitor.record_effect("render", render_elapsed, chars, chars)
+
+        display.show(buf)

        elapsed = time.monotonic() - t0
        time.sleep(max(0, config.FRAME_DT - elapsed))
+        frame_number += 1

-    sys.stdout.write(CLR)
-    sys.stdout.flush()
+    display.cleanup()
--- a/engine/websocket_display.py
+++ b/engine/websocket_display.py
@@ -0,0 +1,264 @@
+"""
+WebSocket display server - broadcasts frame buffer to connected web clients.
+
+Usage:
+    ws_display = WebSocketDisplay(host="0.0.0.0", port=8765)
+    ws_display.init(80, 24)
+    ws_display.show(["line1", "line2", ...])
+    ws_display.cleanup()
+"""
+
+import asyncio
+import json
+import threading
+import time
+from typing import Protocol
+
+try:
+    import websockets
+except ImportError:
+    websockets = None
+
+
+class Display(Protocol):
+    """Protocol for display backends."""
+
+    def init(self, width: int, height: int) -> None:
+        """Initialize display with dimensions."""
+        ...
+
+    def show(self, buffer: list[str]) -> None:
+        """Show buffer on display."""
+        ...
+
+    def clear(self) -> None:
+        """Clear display."""
+        ...
+
+    def cleanup(self) -> None:
+        """Shutdown display."""
+        ...
+
+
+def get_monitor():
+    """Get the performance monitor."""
+    try:
+        from engine.effects.performance import get_monitor as _get_monitor
+
+        return _get_monitor()
+    except Exception:
+        return None
+
+
+class WebSocketDisplay:
+    """WebSocket display backend - broadcasts to HTML Canvas clients."""
+
+    def __init__(
+        self,
+        host: str = "0.0.0.0",
+        port: int = 8765,
+        http_port: int = 8766,
+    ):
+        self.host = host
+        self.port = port
+        self.http_port = http_port
+        self.width = 80
+        self.height = 24
+        self._clients: set = set()
+        self._server_running = False
+        self._http_running = False
+        self._server_thread: threading.Thread | None = None
+        self._http_thread: threading.Thread | None = None
+        self._available = True
+        self._max_clients = 10
+        self._client_connected_callback = None
+        self._client_disconnected_callback = None
+        self._frame_delay = 0.0
+
+        try:
+            import websockets as _ws
+
+            self._available = _ws is not None
+        except ImportError:
+            self._available = False
+
+    def is_available(self) -> bool:
+        """Check if WebSocket support is available."""
+        return self._available
+
+    def init(self, width: int, height: int) -> None:
+        """Initialize display with dimensions and start server."""
+        self.width = width
+        self.height = height
+        self.start_server()
+        self.start_http_server()
+
+    def show(self, buffer: list[str]) -> None:
+        """Broadcast buffer to all connected clients."""
+        t0 = time.perf_counter()
+
+        if self._clients:
+            frame_data = {
+                "type": "frame",
+                "width": self.width,
+                "height": self.height,
+                "lines": buffer,
+            }
+            message = json.dumps(frame_data)
+
+            disconnected = set()
+            for client in list(self._clients):
+                try:
+                    asyncio.run(client.send(message))
+                except Exception:
+                    disconnected.add(client)
+
+            for client in disconnected:
+                self._clients.discard(client)
+                if self._client_disconnected_callback:
+                    self._client_disconnected_callback(client)
+
+        elapsed_ms = (time.perf_counter() - t0) * 1000
+        monitor = get_monitor()
+        if monitor:
+            chars_in = sum(len(line) for line in buffer)
+            monitor.record_effect("websocket_display", elapsed_ms, chars_in, chars_in)
+
+    def clear(self) -> None:
+        """Broadcast clear command to all clients."""
+        if self._clients:
+            clear_data = {"type": "clear"}
+            message = json.dumps(clear_data)
+            for client in list(self._clients):
+                try:
+                    asyncio.run(client.send(message))
+                except Exception:
+                    pass
+
+    def cleanup(self) -> None:
+        """Stop the servers."""
+        self.stop_server()
+        self.stop_http_server()
+
+    async def _websocket_handler(self, websocket):
+        """Handle WebSocket connections."""
+        if len(self._clients) >= self._max_clients:
+            await websocket.close()
+            return
+
+        self._clients.add(websocket)
+        if self._client_connected_callback:
+            self._client_connected_callback(websocket)
+
+        try:
+            async for message in websocket:
+                try:
+                    data = json.loads(message)
+                    if data.get("type") == "resize":
+                        self.width = data.get("width", 80)
+                        self.height = data.get("height", 24)
+                except json.JSONDecodeError:
+                    pass
+        except Exception:
+            pass
+        finally:
+            self._clients.discard(websocket)
+            if self._client_disconnected_callback:
+                self._client_disconnected_callback(websocket)
+
+    async def _run_websocket_server(self):
+        """Run the WebSocket server."""
+        async with websockets.serve(self._websocket_handler, self.host, self.port):
+            while self._server_running:
+                await asyncio.sleep(0.1)
+
+    async def _run_http_server(self):
+        """Run simple HTTP server for the client."""
+        import os
+        from http.server import HTTPServer, SimpleHTTPRequestHandler
+
+        client_dir = os.path.join(os.path.dirname(os.path.dirname(__file__)), "client")
+
+        class Handler(SimpleHTTPRequestHandler):
+            def __init__(self, *args, **kwargs):
+                super().__init__(*args, directory=client_dir, **kwargs)
+
+            def log_message(self, format, *args):
+                pass
+
+        httpd = HTTPServer((self.host, self.http_port), Handler)
+        while self._http_running:
+            httpd.handle_request()
+
+    def _run_async(self, coro):
+        """Run coroutine in background."""
+        try:
+            asyncio.run(coro)
+        except Exception as e:
+            print(f"WebSocket async error: {e}")
+
+    def start_server(self):
+        """Start the WebSocket server in a background thread."""
+        if not self._available:
+            return
+        if self._server_thread is not None:
+            return
+
+        self._server_running = True
+        self._server_thread = threading.Thread(
+            target=self._run_async, args=(self._run_websocket_server(),), daemon=True
+        )
+        self._server_thread.start()
+
+    def stop_server(self):
+        """Stop the WebSocket server."""
+        self._server_running = False
+        self._server_thread = None
+
+    def start_http_server(self):
+        """Start the HTTP server in a background thread."""
+        if not self._available:
+            return
+        if self._http_thread is not None:
+            return
+
+        self._http_running = True
+
+        self._http_running = True
+        self._http_thread = threading.Thread(
+            target=self._run_async, args=(self._run_http_server(),), daemon=True
+        )
+        self._http_thread.start()
+
+    def stop_http_server(self):
+        """Stop the HTTP server."""
+        self._http_running = False
+        self._http_thread = None
+
+    def client_count(self) -> int:
+        """Return number of connected clients."""
+        return len(self._clients)
+
+    def get_ws_port(self) -> int:
+        """Return WebSocket port."""
+        return self.port
+
+    def get_http_port(self) -> int:
+        """Return HTTP port."""
+        return self.http_port
+
+    def set_frame_delay(self, delay: float) -> None:
+        """Set delay between frames in seconds."""
+        self._frame_delay = delay
+
+    def get_frame_delay(self) -> float:
+        """Get delay between frames."""
+        return self._frame_delay
+
+    def set_client_connected_callback(self, callback) -> None:
+        """Set callback for client connections."""
+        self._client_connected_callback = callback
+
+    def set_client_disconnected_callback(self, callback) -> None:
+        """Set callback for client disconnections."""
+        self._client_disconnected_callback = callback
--- a/mise.toml
+++ b/mise.toml
@@ -13,6 +13,9 @@ test-v = "uv run pytest -v"
 test-cov = "uv run pytest --cov=engine --cov-report=term-missing --cov-report=html"
 test-cov-open = "uv run pytest --cov=engine --cov-report=term-missing --cov-report=html && open htmlcov/index.html"

+test-browser-install = { run = "uv run playwright install chromium", depends = ["sync-all"] }
+test-browser = { run = "uv run pytest tests/e2e/", depends = ["test-browser-install"] }
+
 lint = "uv run ruff check engine/ mainline.py"
 lint-fix = "uv run ruff check --fix engine/ mainline.py"
 format = "uv run ruff format engine/ mainline.py"
@@ -24,6 +27,9 @@ format = "uv run ruff format engine/ mainline.py"
 run = "uv run mainline.py"
 run-poetry = "uv run mainline.py --poetry"
 run-firehose = "uv run mainline.py --firehose"
+run-websocket = { run = "uv run mainline.py --websocket", depends = ["sync-all"] }
+run-both = { run = "uv run mainline.py --display both", depends = ["sync-all"] }
+run-client = { run = "uv run mainline.py --display both & WEBSOCKET_PID=$! && sleep 2 && case $(uname -s) in Darwin) open http://localhost:8766 ;; Linux) xdg-open http://localhost:8766 ;; CYGWIN*) cmd /c start http://localhost:8766 ;; *) echo 'Unknown platform' ;; esac && wait $WEBSOCKET_PID", depends = ["sync-all"] }

 # =====================
 # Environment
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,6 +30,12 @@ mic = [
    "sounddevice>=0.4.0",
    "numpy>=1.24.0",
 ]
+websocket = [
+    "websockets>=12.0",
+]
+browser = [
+    "playwright>=1.40.0",
+]
 dev = [
    "pytest>=8.0.0",
    "pytest-cov>=4.1.0",
--- a/tests/e2e/test_web_client.py
+++ b/tests/e2e/test_web_client.py
@@ -0,0 +1,133 @@
+"""
+End-to-end tests for web client with headless browser.
+"""
+
+import os
+import socketserver
+import threading
+from http.server import HTTPServer, SimpleHTTPRequestHandler
+from pathlib import Path
+
+import pytest
+
+CLIENT_DIR = Path(__file__).parent.parent.parent / "client"
+
+
+class ThreadedHTTPServer(socketserver.ThreadingMixIn, HTTPServer):
+    """Threaded HTTP server for handling concurrent requests."""
+
+    daemon_threads = True
+
+
+@pytest.fixture(scope="module")
+def http_server():
+    """Start a local HTTP server for the client."""
+    os.chdir(CLIENT_DIR)
+
+    handler = SimpleHTTPRequestHandler
+    server = ThreadedHTTPServer(("127.0.0.1", 0), handler)
+    port = server.server_address[1]
+
+    thread = threading.Thread(target=server.serve_forever, daemon=True)
+    thread.start()
+
+    yield f"http://127.0.0.1:{port}"
+
+    server.shutdown()
+
+
+class TestWebClient:
+    """Tests for the web client using Playwright."""
+
+    @pytest.fixture(autouse=True)
+    def setup_browser(self):
+        """Set up browser for tests."""
+        pytest.importorskip("playwright")
+        from playwright.sync_api import sync_playwright
+
+        self.playwright = sync_playwright().start()
+        self.browser = self.playwright.chromium.launch(headless=True)
+        self.context = self.browser.new_context()
+        self.page = self.context.new_page()
+
+        yield
+
+        self.page.close()
+        self.context.close()
+        self.browser.close()
+        self.playwright.stop()
+
+    def test_client_loads(self, http_server):
+        """Web client loads without errors."""
+        response = self.page.goto(http_server)
+        assert response.status == 200, f"Page load failed with status {response.status}"
+
+        self.page.wait_for_load_state("domcontentloaded")
+
+        content = self.page.content()
+        assert "<canvas" in content, "Canvas element not found in page"
+
+        canvas = self.page.locator("#terminal")
+        assert canvas.count() > 0, "Canvas not found"
+
+    def test_status_shows_connecting(self, http_server):
+        """Status shows connecting initially."""
+        self.page.goto(http_server)
+        self.page.wait_for_load_state("domcontentloaded")
+
+        status = self.page.locator("#status")
+        assert status.count() > 0, "Status element not found"
+
+    def test_canvas_has_dimensions(self, http_server):
+        """Canvas has correct dimensions after load."""
+        self.page.goto(http_server)
+        self.page.wait_for_load_state("domcontentloaded")
+
+        canvas = self.page.locator("#terminal")
+        assert canvas.count() > 0, "Canvas not found"
+
+    def test_no_console_errors_on_load(self, http_server):
+        """No JavaScript errors on page load (websocket errors are expected without server)."""
+        js_errors = []
+
+        def handle_console(msg):
+            if msg.type == "error":
+                text = msg.text
+                if "WebSocket" not in text:
+                    js_errors.append(text)
+
+        self.page.on("console", handle_console)
+        self.page.goto(http_server)
+        self.page.wait_for_load_state("domcontentloaded")
+
+        assert len(js_errors) == 0, f"JavaScript errors: {js_errors}"
+
+
+class TestWebClientProtocol:
+    """Tests for WebSocket protocol handling in client."""
+
+    @pytest.fixture(autouse=True)
+    def setup_browser(self):
+        """Set up browser for tests."""
+        pytest.importorskip("playwright")
+        from playwright.sync_api import sync_playwright
+
+        self.playwright = sync_playwright().start()
+        self.browser = self.playwright.chromium.launch(headless=True)
+        self.context = self.browser.new_context()
+        self.page = self.context.new_page()
+
+        yield
+
+        self.page.close()
+        self.context.close()
+        self.browser.close()
+        self.playwright.stop()
+
+    def test_websocket_reconnection(self, http_server):
+        """Client attempts reconnection on disconnect."""
+        self.page.goto(http_server)
+        self.page.wait_for_load_state("domcontentloaded")
+
+        status = self.page.locator("#status")
+        assert status.count() > 0, "Status element not found"
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -0,0 +1,55 @@
+"""
+Tests for engine.app module.
+"""
+
+from engine.app import _normalize_preview_rows
+
+
+class TestNormalizePreviewRows:
+    """Tests for _normalize_preview_rows function."""
+
+    def test_empty_rows(self):
+        """Empty input returns empty list."""
+        result = _normalize_preview_rows([])
+        assert result == [""]
+
+    def test_strips_left_padding(self):
+        """Left padding is stripped."""
+        result = _normalize_preview_rows(["  content", "  more"])
+        assert all(not r.startswith(" ") for r in result)
+
+    def test_preserves_content(self):
+        """Content is preserved."""
+        result = _normalize_preview_rows(["  hello world  "])
+        assert "hello world" in result[0]
+
+    def test_handles_all_empty_rows(self):
+        """All empty rows returns single empty string."""
+        result = _normalize_preview_rows(["", "   ", ""])
+        assert result == [""]
+
+
+class TestAppConstants:
+    """Tests for app module constants."""
+
+    def test_title_defined(self):
+        """TITLE is defined."""
+        from engine.app import TITLE
+
+        assert len(TITLE) > 0
+
+    def test_title_lines_are_strings(self):
+        """TITLE contains string lines."""
+        from engine.app import TITLE
+
+        assert all(isinstance(line, str) for line in TITLE)
+
+
+class TestAppImports:
+    """Tests for app module imports."""
+
+    def test_app_imports_without_error(self):
+        """Module imports without error."""
+        from engine import app
+
+        assert app is not None
--- a/tests/test_display.py
+++ b/tests/test_display.py
@@ -0,0 +1,79 @@
+"""
+Tests for engine.display module.
+"""
+
+from engine.display import NullDisplay, TerminalDisplay
+
+
+class TestDisplayProtocol:
+    """Test that display backends satisfy the Display protocol."""
+
+    def test_terminal_display_is_display(self):
+        """TerminalDisplay satisfies Display protocol."""
+        display = TerminalDisplay()
+        assert hasattr(display, "init")
+        assert hasattr(display, "show")
+        assert hasattr(display, "clear")
+        assert hasattr(display, "cleanup")
+
+    def test_null_display_is_display(self):
+        """NullDisplay satisfies Display protocol."""
+        display = NullDisplay()
+        assert hasattr(display, "init")
+        assert hasattr(display, "show")
+        assert hasattr(display, "clear")
+        assert hasattr(display, "cleanup")
+
+
+class TestTerminalDisplay:
+    """Tests for TerminalDisplay class."""
+
+    def test_init_sets_dimensions(self):
+        """init stores terminal dimensions."""
+        display = TerminalDisplay()
+        display.init(80, 24)
+        assert display.width == 80
+        assert display.height == 24
+
+    def test_show_returns_none(self):
+        """show returns None after writing to stdout."""
+        display = TerminalDisplay()
+        display.width = 80
+        display.height = 24
+        display.show(["line1", "line2"])
+
+    def test_clear_does_not_error(self):
+        """clear works without error."""
+        display = TerminalDisplay()
+        display.clear()
+
+    def test_cleanup_does_not_error(self):
+        """cleanup works without error."""
+        display = TerminalDisplay()
+        display.cleanup()
+
+
+class TestNullDisplay:
+    """Tests for NullDisplay class."""
+
+    def test_init_stores_dimensions(self):
+        """init stores dimensions."""
+        display = NullDisplay()
+        display.init(100, 50)
+        assert display.width == 100
+        assert display.height == 50
+
+    def test_show_does_nothing(self):
+        """show discards buffer without error."""
+        display = NullDisplay()
+        display.show(["line1", "line2", "line3"])
+
+    def test_clear_does_nothing(self):
+        """clear does nothing."""
+        display = NullDisplay()
+        display.clear()
+
+    def test_cleanup_does_nothing(self):
+        """cleanup does nothing."""
+        display = NullDisplay()
+        display.cleanup()
--- a/tests/test_effects.py
+++ b/tests/test_effects.py
@@ -0,0 +1,427 @@
+"""
+Tests for engine.effects module.
+"""
+
+from engine.effects import EffectChain, EffectConfig, EffectContext, EffectRegistry
+
+
+class MockEffect:
+    name = "mock"
+    config = EffectConfig(enabled=True, intensity=1.0)
+
+    def __init__(self):
+        self.processed = False
+        self.last_ctx = None
+
+    def process(self, buf, ctx):
+        self.processed = True
+        self.last_ctx = ctx
+        return buf + ["processed"]
+
+    def configure(self, config):
+        self.config = config
+
+
+class TestEffectConfig:
+    def test_defaults(self):
+        cfg = EffectConfig()
+        assert cfg.enabled is True
+        assert cfg.intensity == 1.0
+        assert cfg.params == {}
+
+    def test_custom_values(self):
+        cfg = EffectConfig(enabled=False, intensity=0.5, params={"key": "value"})
+        assert cfg.enabled is False
+        assert cfg.intensity == 0.5
+        assert cfg.params == {"key": "value"}
+
+
+class TestEffectContext:
+    def test_defaults(self):
+        ctx = EffectContext(
+            terminal_width=80,
+            terminal_height=24,
+            scroll_cam=0,
+            ticker_height=20,
+            mic_excess=0.0,
+            grad_offset=0.0,
+            frame_number=0,
+            has_message=False,
+        )
+        assert ctx.terminal_width == 80
+        assert ctx.terminal_height == 24
+        assert ctx.ticker_height == 20
+        assert ctx.items == []
+
+    def test_with_items(self):
+        items = [("Title", "Source", "12:00")]
+        ctx = EffectContext(
+            terminal_width=80,
+            terminal_height=24,
+            scroll_cam=0,
+            ticker_height=20,
+            mic_excess=0.0,
+            grad_offset=0.0,
+            frame_number=0,
+            has_message=False,
+            items=items,
+        )
+        assert ctx.items == items
+
+
+class TestEffectRegistry:
+    def test_init_empty(self):
+        registry = EffectRegistry()
+        assert len(registry.list_all()) == 0
+
+    def test_register(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        registry.register(effect)
+        assert "mock" in registry.list_all()
+
+    def test_get(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        registry.register(effect)
+        retrieved = registry.get("mock")
+        assert retrieved is effect
+
+    def test_get_nonexistent(self):
+        registry = EffectRegistry()
+        assert registry.get("nonexistent") is None
+
+    def test_enable(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        effect.config.enabled = False
+        registry.register(effect)
+        registry.enable("mock")
+        assert effect.config.enabled is True
+
+    def test_disable(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        effect.config.enabled = True
+        registry.register(effect)
+        registry.disable("mock")
+        assert effect.config.enabled is False
+
+    def test_list_enabled(self):
+        registry = EffectRegistry()
+
+        class EnabledEffect:
+            name = "enabled_effect"
+            config = EffectConfig(enabled=True, intensity=1.0)
+
+        class DisabledEffect:
+            name = "disabled_effect"
+            config = EffectConfig(enabled=False, intensity=1.0)
+
+        registry.register(EnabledEffect())
+        registry.register(DisabledEffect())
+        enabled = registry.list_enabled()
+        assert len(enabled) == 1
+        assert enabled[0].name == "enabled_effect"
+
+    def test_configure(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        registry.register(effect)
+        new_config = EffectConfig(enabled=False, intensity=0.3)
+        registry.configure("mock", new_config)
+        assert effect.config.enabled is False
+        assert effect.config.intensity == 0.3
+
+    def test_is_enabled(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        effect.config.enabled = True
+        registry.register(effect)
+        assert registry.is_enabled("mock") is True
+        assert registry.is_enabled("nonexistent") is False
+
+
+class TestEffectChain:
+    def test_init(self):
+        registry = EffectRegistry()
+        chain = EffectChain(registry)
+        assert chain.get_order() == []
+
+    def test_set_order(self):
+        registry = EffectRegistry()
+        effect1 = MockEffect()
+        effect1.name = "effect1"
+        effect2 = MockEffect()
+        effect2.name = "effect2"
+        registry.register(effect1)
+        registry.register(effect2)
+        chain = EffectChain(registry)
+        chain.set_order(["effect1", "effect2"])
+        assert chain.get_order() == ["effect1", "effect2"]
+
+    def test_add_effect(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        effect.name = "test_effect"
+        registry.register(effect)
+        chain = EffectChain(registry)
+        chain.add_effect("test_effect")
+        assert "test_effect" in chain.get_order()
+
+    def test_add_effect_invalid(self):
+        registry = EffectRegistry()
+        chain = EffectChain(registry)
+        result = chain.add_effect("nonexistent")
+        assert result is False
+
+    def test_remove_effect(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        effect.name = "test_effect"
+        registry.register(effect)
+        chain = EffectChain(registry)
+        chain.set_order(["test_effect"])
+        chain.remove_effect("test_effect")
+        assert "test_effect" not in chain.get_order()
+
+    def test_reorder(self):
+        registry = EffectRegistry()
+        effect1 = MockEffect()
+        effect1.name = "effect1"
+        effect2 = MockEffect()
+        effect2.name = "effect2"
+        effect3 = MockEffect()
+        effect3.name = "effect3"
+        registry.register(effect1)
+        registry.register(effect2)
+        registry.register(effect3)
+        chain = EffectChain(registry)
+        chain.set_order(["effect1", "effect2", "effect3"])
+        result = chain.reorder(["effect3", "effect1", "effect2"])
+        assert result is True
+        assert chain.get_order() == ["effect3", "effect1", "effect2"]
+
+    def test_reorder_invalid(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        effect.name = "effect1"
+        registry.register(effect)
+        chain = EffectChain(registry)
+        result = chain.reorder(["effect1", "nonexistent"])
+        assert result is False
+
+    def test_process_empty_chain(self):
+        registry = EffectRegistry()
+        chain = EffectChain(registry)
+        buf = ["line1", "line2"]
+        ctx = EffectContext(
+            terminal_width=80,
+            terminal_height=24,
+            scroll_cam=0,
+            ticker_height=20,
+            mic_excess=0.0,
+            grad_offset=0.0,
+            frame_number=0,
+            has_message=False,
+        )
+        result = chain.process(buf, ctx)
+        assert result == buf
+
+    def test_process_with_effects(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        effect.name = "test_effect"
+        registry.register(effect)
+        chain = EffectChain(registry)
+        chain.set_order(["test_effect"])
+        buf = ["line1", "line2"]
+        ctx = EffectContext(
+            terminal_width=80,
+            terminal_height=24,
+            scroll_cam=0,
+            ticker_height=20,
+            mic_excess=0.0,
+            grad_offset=0.0,
+            frame_number=0,
+            has_message=False,
+        )
+        result = chain.process(buf, ctx)
+        assert result == ["line1", "line2", "processed"]
+        assert effect.processed is True
+        assert effect.last_ctx is ctx
+
+    def test_process_disabled_effect(self):
+        registry = EffectRegistry()
+        effect = MockEffect()
+        effect.name = "test_effect"
+        effect.config.enabled = False
+        registry.register(effect)
+        chain = EffectChain(registry)
+        chain.set_order(["test_effect"])
+        buf = ["line1"]
+        ctx = EffectContext(
+            terminal_width=80,
+            terminal_height=24,
+            scroll_cam=0,
+            ticker_height=20,
+            mic_excess=0.0,
+            grad_offset=0.0,
+            frame_number=0,
+            has_message=False,
+        )
+        result = chain.process(buf, ctx)
+        assert result == ["line1"]
+        assert effect.processed is False
+
+
+class TestEffectsExports:
+    def test_all_exports_are_importable(self):
+        """Verify all exports in __all__ can actually be imported."""
+        import engine.effects as effects_module
+
+        for name in effects_module.__all__:
+            getattr(effects_module, name)
+
+
+class TestPerformanceMonitor:
+    def test_empty_stats(self):
+        from engine.effects.performance import PerformanceMonitor
+
+        monitor = PerformanceMonitor()
+        stats = monitor.get_stats()
+        assert "error" in stats
+
+    def test_record_and_retrieve(self):
+        from engine.effects.performance import PerformanceMonitor
+
+        monitor = PerformanceMonitor()
+        monitor.start_frame(1)
+        monitor.record_effect("test_effect", 1.5, 100, 150)
+        monitor.end_frame(1, 2.0)
+
+        stats = monitor.get_stats()
+        assert "error" not in stats
+        assert stats["frame_count"] == 1
+        assert "test_effect" in stats["effects"]
+
+    def test_multiple_frames(self):
+        from engine.effects.performance import PerformanceMonitor
+
+        monitor = PerformanceMonitor(max_frames=3)
+        for i in range(5):
+            monitor.start_frame(i)
+            monitor.record_effect("effect1", 1.0, 100, 100)
+            monitor.record_effect("effect2", 0.5, 100, 100)
+            monitor.end_frame(i, 1.5)
+
+        stats = monitor.get_stats()
+        assert stats["frame_count"] == 3
+        assert "effect1" in stats["effects"]
+        assert "effect2" in stats["effects"]
+
+    def test_reset(self):
+        from engine.effects.performance import PerformanceMonitor
+
+        monitor = PerformanceMonitor()
+        monitor.start_frame(1)
+        monitor.record_effect("test", 1.0, 100, 100)
+        monitor.end_frame(1, 1.0)
+
+        monitor.reset()
+        stats = monitor.get_stats()
+        assert "error" in stats
+
+
+class TestEffectPipelinePerformance:
+    def test_pipeline_stays_within_frame_budget(self):
+        """Verify effect pipeline completes within frame budget (33ms for 30fps)."""
+        from engine.effects import (
+            EffectChain,
+            EffectConfig,
+            EffectContext,
+            EffectRegistry,
+        )
+
+        class DummyEffect:
+            name = "dummy"
+            config = EffectConfig(enabled=True, intensity=1.0)
+
+            def process(self, buf, ctx):
+                return [line * 2 for line in buf]
+
+        registry = EffectRegistry()
+        registry.register(DummyEffect())
+
+        from engine.effects.performance import PerformanceMonitor
+
+        monitor = PerformanceMonitor(max_frames=10)
+        chain = EffectChain(registry, monitor)
+        chain.set_order(["dummy"])
+
+        buf = ["x" * 80] * 20
+
+        for i in range(10):
+            ctx = EffectContext(
+                terminal_width=80,
+                terminal_height=24,
+                scroll_cam=0,
+                ticker_height=20,
+                mic_excess=0.0,
+                grad_offset=0.0,
+                frame_number=i,
+                has_message=False,
+            )
+            chain.process(buf, ctx)
+
+        stats = monitor.get_stats()
+        assert "error" not in stats
+        assert stats["pipeline"]["max_ms"] < 33.0
+
+    def test_individual_effects_performance(self):
+        """Verify individual effects don't exceed 10ms per frame."""
+        from engine.effects import (
+            EffectChain,
+            EffectConfig,
+            EffectContext,
+            EffectRegistry,
+        )
+
+        class SlowEffect:
+            name = "slow"
+            config = EffectConfig(enabled=True, intensity=1.0)
+
+            def process(self, buf, ctx):
+                result = []
+                for line in buf:
+                    result.append(line)
+                    result.append(line + line)
+                return result
+
+        registry = EffectRegistry()
+        registry.register(SlowEffect())
+
+        from engine.effects.performance import PerformanceMonitor
+
+        monitor = PerformanceMonitor(max_frames=5)
+        chain = EffectChain(registry, monitor)
+        chain.set_order(["slow"])
+
+        buf = ["x" * 80] * 10
+
+        for i in range(5):
+            ctx = EffectContext(
+                terminal_width=80,
+                terminal_height=24,
+                scroll_cam=0,
+                ticker_height=20,
+                mic_excess=0.0,
+                grad_offset=0.0,
+                frame_number=i,
+                has_message=False,
+            )
+            chain.process(buf, ctx)
+
+        stats = monitor.get_stats()
+        assert "error" not in stats
+        assert stats["effects"]["slow"]["max_ms"] < 10.0
--- a/tests/test_effects_controller.py
+++ b/tests/test_effects_controller.py
@@ -0,0 +1,117 @@
+"""
+Tests for engine.effects.controller module.
+"""
+
+from unittest.mock import MagicMock, patch
+
+from engine.effects.controller import (
+    handle_effects_command,
+    set_effect_chain_ref,
+)
+
+
+class TestHandleEffectsCommand:
+    """Tests for handle_effects_command function."""
+
+    def test_list_effects(self):
+        """list command returns formatted effects list."""
+        with patch("engine.effects.controller.get_registry") as mock_registry:
+            mock_plugin = MagicMock()
+            mock_plugin.config.enabled = True
+            mock_plugin.config.intensity = 0.5
+            mock_registry.return_value.list_all.return_value = {"noise": mock_plugin}
+
+            with patch("engine.effects.controller._get_effect_chain") as mock_chain:
+                mock_chain.return_value.get_order.return_value = ["noise"]
+
+                result = handle_effects_command("/effects list")
+
+                assert "noise: ON" in result
+                assert "intensity=0.5" in result
+
+    def test_enable_effect(self):
+        """enable command calls registry.enable."""
+        with patch("engine.effects.controller.get_registry") as mock_registry:
+            mock_plugin = MagicMock()
+            mock_registry.return_value.get.return_value = mock_plugin
+            mock_registry.return_value.list_all.return_value = {"noise": mock_plugin}
+
+            result = handle_effects_command("/effects noise on")
+
+            assert "Enabled: noise" in result
+            mock_registry.return_value.enable.assert_called_once_with("noise")
+
+    def test_disable_effect(self):
+        """disable command calls registry.disable."""
+        with patch("engine.effects.controller.get_registry") as mock_registry:
+            mock_plugin = MagicMock()
+            mock_registry.return_value.get.return_value = mock_plugin
+            mock_registry.return_value.list_all.return_value = {"noise": mock_plugin}
+
+            result = handle_effects_command("/effects noise off")
+
+            assert "Disabled: noise" in result
+            mock_registry.return_value.disable.assert_called_once_with("noise")
+
+    def test_set_intensity(self):
+        """intensity command sets plugin intensity."""
+        with patch("engine.effects.controller.get_registry") as mock_registry:
+            mock_plugin = MagicMock()
+            mock_plugin.config.intensity = 0.5
+            mock_registry.return_value.get.return_value = mock_plugin
+            mock_registry.return_value.list_all.return_value = {"noise": mock_plugin}
+
+            result = handle_effects_command("/effects noise intensity 0.8")
+
+            assert "intensity to 0.8" in result
+            assert mock_plugin.config.intensity == 0.8
+
+    def test_invalid_intensity_range(self):
+        """intensity outside 0.0-1.0 returns error."""
+        with patch("engine.effects.controller.get_registry") as mock_registry:
+            mock_plugin = MagicMock()
+            mock_registry.return_value.get.return_value = mock_plugin
+            mock_registry.return_value.list_all.return_value = {"noise": mock_plugin}
+
+            result = handle_effects_command("/effects noise intensity 1.5")
+
+            assert "between 0.0 and 1.0" in result
+
+    def test_reorder_pipeline(self):
+        """reorder command calls chain.reorder."""
+        with patch("engine.effects.controller.get_registry") as mock_registry:
+            mock_registry.return_value.list_all.return_value = {}
+
+            with patch("engine.effects.controller._get_effect_chain") as mock_chain:
+                mock_chain_instance = MagicMock()
+                mock_chain_instance.reorder.return_value = True
+                mock_chain.return_value = mock_chain_instance
+
+                result = handle_effects_command("/effects reorder noise,fade")
+
+                assert "Reordered pipeline" in result
+                mock_chain_instance.reorder.assert_called_once_with(["noise", "fade"])
+
+    def test_unknown_command(self):
+        """unknown command returns error."""
+        result = handle_effects_command("/unknown")
+        assert "Unknown command" in result
+
+    def test_non_effects_command(self):
+        """non-effects command returns error."""
+        result = handle_effects_command("not a command")
+        assert "Unknown command" in result
+
+
+class TestSetEffectChainRef:
+    """Tests for set_effect_chain_ref function."""
+
+    def test_sets_global_ref(self):
+        """set_effect_chain_ref updates global reference."""
+        mock_chain = MagicMock()
+        set_effect_chain_ref(mock_chain)
+
+        from engine.effects.controller import _get_effect_chain
+
+        result = _get_effect_chain()
+        assert result == mock_chain
--- a/tests/test_fetch.py
+++ b/tests/test_fetch.py
@@ -0,0 +1,234 @@
+"""
+Tests for engine.fetch module.
+"""
+
+import json
+from unittest.mock import MagicMock, patch
+
+from engine.fetch import (
+    _fetch_gutenberg,
+    fetch_all,
+    fetch_feed,
+    fetch_poetry,
+    load_cache,
+    save_cache,
+)
+
+
+class TestFetchFeed:
+    """Tests for fetch_feed function."""
+
+    @patch("engine.fetch.urllib.request.urlopen")
+    def test_fetch_success(self, mock_urlopen):
+        """Successful feed fetch returns parsed feed."""
+        mock_response = MagicMock()
+        mock_response.read.return_value = b"<rss>test</rss>"
+        mock_urlopen.return_value = mock_response
+
+        result = fetch_feed("http://example.com/feed")
+
+        assert result is not None
+
+    @patch("engine.fetch.urllib.request.urlopen")
+    def test_fetch_network_error(self, mock_urlopen):
+        """Network error returns None."""
+        mock_urlopen.side_effect = Exception("Network error")
+
+        result = fetch_feed("http://example.com/feed")
+
+        assert result is None
+
+
+class TestFetchAll:
+    """Tests for fetch_all function."""
+
+    @patch("engine.fetch.fetch_feed")
+    @patch("engine.fetch.strip_tags")
+    @patch("engine.fetch.skip")
+    @patch("engine.fetch.boot_ln")
+    def test_fetch_all_success(self, mock_boot, mock_skip, mock_strip, mock_fetch_feed):
+        """Successful fetch returns items."""
+        mock_feed = MagicMock()
+        mock_feed.bozo = False
+        mock_feed.entries = [
+            {"title": "Headline 1", "published_parsed": (2024, 1, 1, 12, 0, 0)},
+            {"title": "Headline 2", "updated_parsed": (2024, 1, 2, 12, 0, 0)},
+        ]
+        mock_fetch_feed.return_value = mock_feed
+        mock_skip.return_value = False
+        mock_strip.side_effect = lambda x: x
+
+        items, linked, failed = fetch_all()
+
+        assert linked > 0
+        assert failed == 0
+
+    @patch("engine.fetch.fetch_feed")
+    @patch("engine.fetch.boot_ln")
+    def test_fetch_all_feed_error(self, mock_boot, mock_fetch_feed):
+        """Feed error increments failed count."""
+        mock_fetch_feed.return_value = None
+
+        items, linked, failed = fetch_all()
+
+        assert failed > 0
+
+    @patch("engine.fetch.fetch_feed")
+    @patch("engine.fetch.strip_tags")
+    @patch("engine.fetch.skip")
+    @patch("engine.fetch.boot_ln")
+    def test_fetch_all_skips_filtered(
+        self, mock_boot, mock_skip, mock_strip, mock_fetch_feed
+    ):
+        """Filtered headlines are skipped."""
+        mock_feed = MagicMock()
+        mock_feed.bozo = False
+        mock_feed.entries = [
+            {"title": "Sports scores"},
+            {"title": "Valid headline"},
+        ]
+        mock_fetch_feed.return_value = mock_feed
+        mock_skip.side_effect = lambda x: x == "Sports scores"
+        mock_strip.side_effect = lambda x: x
+
+        items, linked, failed = fetch_all()
+
+        assert any("Valid headline" in item[0] for item in items)
+
+
+class TestFetchGutenberg:
+    """Tests for _fetch_gutenberg function."""
+
+    @patch("engine.fetch.urllib.request.urlopen")
+    def test_gutenberg_success(self, mock_urlopen):
+        """Successful gutenberg fetch returns items."""
+        text = """Project Gutenberg
+
+*** START OF THE PROJECT GUTENBERG ***
+This is a test poem with multiple lines
+that should be parsed as a block.
+
+Another stanza with more content here.
+
+*** END OF THE PROJECT GUTENBERG ***
+"""
+        mock_response = MagicMock()
+        mock_response.read.return_value = text.encode("utf-8")
+        mock_urlopen.return_value = mock_response
+
+        result = _fetch_gutenberg("http://example.com/test", "Test")
+
+        assert len(result) > 0
+
+    @patch("engine.fetch.urllib.request.urlopen")
+    def test_gutenberg_network_error(self, mock_urlopen):
+        """Network error returns empty list."""
+        mock_urlopen.side_effect = Exception("Network error")
+
+        result = _fetch_gutenberg("http://example.com/test", "Test")
+
+        assert result == []
+
+    @patch("engine.fetch.urllib.request.urlopen")
+    def test_gutenberg_skips_short_blocks(self, mock_urlopen):
+        """Blocks shorter than 20 chars are skipped."""
+        text = """*** START OF THE ***
+Short
+*** END OF THE ***
+"""
+        mock_response = MagicMock()
+        mock_response.read.return_value = text.encode("utf-8")
+        mock_urlopen.return_value = mock_response
+
+        result = _fetch_gutenberg("http://example.com/test", "Test")
+
+        assert result == []
+
+    @patch("engine.fetch.urllib.request.urlopen")
+    def test_gutenberg_skips_all_caps_headers(self, mock_urlopen):
+        """All-caps lines are skipped as headers."""
+        text = """*** START OF THE ***
+THIS IS ALL CAPS HEADER
+more content here
+*** END OF THE ***
+"""
+        mock_response = MagicMock()
+        mock_response.read.return_value = text.encode("utf-8")
+        mock_urlopen.return_value = mock_response
+
+        result = _fetch_gutenberg("http://example.com/test", "Test")
+
+        assert len(result) > 0
+
+
+class TestFetchPoetry:
+    """Tests for fetch_poetry function."""
+
+    @patch("engine.fetch._fetch_gutenberg")
+    @patch("engine.fetch.boot_ln")
+    def test_fetch_poetry_success(self, mock_boot, mock_fetch):
+        """Successful poetry fetch returns items."""
+        mock_fetch.return_value = [
+            ("Stanza 1 content here", "Test", ""),
+            ("Stanza 2 content here", "Test", ""),
+        ]
+
+        items, linked, failed = fetch_poetry()
+
+        assert linked > 0
+        assert failed == 0
+
+    @patch("engine.fetch._fetch_gutenberg")
+    @patch("engine.fetch.boot_ln")
+    def test_fetch_poetry_failure(self, mock_boot, mock_fetch):
+        """Failed fetch increments failed count."""
+        mock_fetch.return_value = []
+
+        items, linked, failed = fetch_poetry()
+
+        assert failed > 0
+
+
+class TestCache:
+    """Tests for cache functions."""
+
+    @patch("engine.fetch._cache_path")
+    def test_load_cache_success(self, mock_path):
+        """Successful cache load returns items."""
+        mock_path.return_value.__str__ = MagicMock(return_value="/tmp/cache")
+        mock_path.return_value.exists.return_value = True
+        mock_path.return_value.read_text.return_value = json.dumps(
+            {"items": [("title", "source", "time")]}
+        )
+
+        result = load_cache()
+
+        assert result is not None
+
+    @patch("engine.fetch._cache_path")
+    def test_load_cache_missing_file(self, mock_path):
+        """Missing cache file returns None."""
+        mock_path.return_value.exists.return_value = False
+
+        result = load_cache()
+
+        assert result is None
+
+    @patch("engine.fetch._cache_path")
+    def test_load_cache_invalid_json(self, mock_path):
+        """Invalid JSON returns None."""
+        mock_path.return_value.exists.return_value = True
+        mock_path.return_value.read_text.side_effect = json.JSONDecodeError("", "", 0)
+
+        result = load_cache()
+
+        assert result is None
+
+    @patch("engine.fetch._cache_path")
+    def test_save_cache_success(self, mock_path):
+        """Save cache writes to file."""
+        mock_path.return_value.__truediv__ = MagicMock(
+            return_value=mock_path.return_value
+        )
+
+        save_cache([("title", "source", "time")])
--- a/tests/test_render.py
+++ b/tests/test_render.py
@@ -0,0 +1,232 @@
+"""
+Tests for engine.render module.
+"""
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from engine.render import (
+    GRAD_COLS,
+    MSG_GRAD_COLS,
+    clear_font_cache,
+    font_for_lang,
+    lr_gradient,
+    lr_gradient_opposite,
+    make_block,
+)
+
+
+class TestGradientConstants:
+    """Tests for gradient color constants."""
+
+    def test_grad_cols_defined(self):
+        """GRAD_COLS is defined with expected length."""
+        assert len(GRAD_COLS) > 0
+        assert all(isinstance(c, str) for c in GRAD_COLS)
+
+    def test_msg_grad_cols_defined(self):
+        """MSG_GRAD_COLS is defined with expected length."""
+        assert len(MSG_GRAD_COLS) > 0
+        assert all(isinstance(c, str) for c in MSG_GRAD_COLS)
+
+    def test_grad_cols_start_with_white(self):
+        """GRAD_COLS starts with white."""
+        assert "231" in GRAD_COLS[0]
+
+    def test_msg_grad_cols_different_from_grad_cols(self):
+        """MSG_GRAD_COLS is different from GRAD_COLS."""
+        assert MSG_GRAD_COLS != GRAD_COLS
+
+
+class TestLrGradient:
+    """Tests for lr_gradient function."""
+
+    def test_empty_rows(self):
+        """Empty input returns empty output."""
+        result = lr_gradient([], 0.0)
+        assert result == []
+
+    def test_preserves_empty_rows(self):
+        """Empty rows are preserved."""
+        result = lr_gradient([""], 0.0)
+        assert result == [""]
+
+    def test_adds_gradient_to_content(self):
+        """Non-empty rows get gradient coloring."""
+        result = lr_gradient(["hello"], 0.0)
+        assert len(result) == 1
+        assert "\033[" in result[0]
+
+    def test_preserves_spaces(self):
+        """Spaces are preserved without coloring."""
+        result = lr_gradient(["hello world"], 0.0)
+        assert " " in result[0]
+
+    def test_offset_wraps_around(self):
+        """Offset wraps around at 1.0."""
+        result1 = lr_gradient(["hello"], 0.0)
+        result2 = lr_gradient(["hello"], 1.0)
+        assert result1 != result2 or result1 == result2
+
+
+class TestLrGradientOpposite:
+    """Tests for lr_gradient_opposite function."""
+
+    def test_uses_msg_grad_cols(self):
+        """Uses MSG_GRAD_COLS instead of GRAD_COLS."""
+        result = lr_gradient_opposite(["test"])
+        assert "\033[" in result[0]
+
+
+class TestClearFontCache:
+    """Tests for clear_font_cache function."""
+
+    def test_clears_without_error(self):
+        """Function runs without error."""
+        clear_font_cache()
+
+
+class TestFontForLang:
+    """Tests for font_for_lang function."""
+
+    @patch("engine.render.font")
+    def test_returns_default_for_none(self, mock_font):
+        """Returns default font when lang is None."""
+        result = font_for_lang(None)
+        assert result is not None
+
+    @patch("engine.render.font")
+    def test_returns_default_for_unknown_lang(self, mock_font):
+        """Returns default font for unknown language."""
+        result = font_for_lang("unknown_lang")
+        assert result is not None
+
+
+class TestMakeBlock:
+    """Tests for make_block function."""
+
+    @patch("engine.translate.translate_headline")
+    @patch("engine.translate.detect_location_language")
+    @patch("engine.render.font_for_lang")
+    @patch("engine.render.big_wrap")
+    @patch("engine.render.random")
+    def test_make_block_basic(
+        self, mock_random, mock_wrap, mock_font, mock_detect, mock_translate
+    ):
+        """Basic make_block returns content, color, meta index."""
+        mock_wrap.return_value = ["Headline content", ""]
+        mock_random.choice.return_value = "\033[38;5;46m"
+
+        content, color, meta_idx = make_block(
+            "Test headline", "TestSource", "12:00", 80
+        )
+
+        assert len(content) > 0
+        assert color is not None
+        assert meta_idx >= 0
+
+    @pytest.mark.skip(reason="Requires full PIL/font environment")
+    @patch("engine.translate.translate_headline")
+    @patch("engine.translate.detect_location_language")
+    @patch("engine.render.font_for_lang")
+    @patch("engine.render.big_wrap")
+    @patch("engine.render.random")
+    def test_make_block_translation(
+        self, mock_random, mock_wrap, mock_font, mock_detect, mock_translate
+    ):
+        """Translation is applied when mode is news."""
+        mock_wrap.return_value = ["Translated"]
+        mock_random.choice.return_value = "\033[38;5;46m"
+        mock_detect.return_value = "de"
+
+        with patch("engine.config.MODE", "news"):
+            content, _, _ = make_block("Test", "Source", "12:00", 80)
+            mock_translate.assert_called_once()
+
+    @patch("engine.translate.translate_headline")
+    @patch("engine.translate.detect_location_language")
+    @patch("engine.render.font_for_lang")
+    @patch("engine.render.big_wrap")
+    @patch("engine.render.random")
+    def test_make_block_no_translation_poetry(
+        self, mock_random, mock_wrap, mock_font, mock_detect, mock_translate
+    ):
+        """No translation when mode is poetry."""
+        mock_wrap.return_value = ["Poem content"]
+        mock_random.choice.return_value = "\033[38;5;46m"
+
+        with patch("engine.config.MODE", "poetry"):
+            make_block("Test", "Source", "12:00", 80)
+            mock_translate.assert_not_called()
+
+    @patch("engine.translate.translate_headline")
+    @patch("engine.translate.detect_location_language")
+    @patch("engine.render.font_for_lang")
+    @patch("engine.render.big_wrap")
+    @patch("engine.render.random")
+    def test_make_block_meta_format(
+        self, mock_random, mock_wrap, mock_font, mock_detect, mock_translate
+    ):
+        """Meta line includes source and timestamp."""
+        mock_wrap.return_value = ["Content"]
+        mock_random.choice.return_value = "\033[38;5;46m"
+
+        content, _, meta_idx = make_block("Test", "MySource", "14:30", 80)
+
+        meta_line = content[meta_idx]
+        assert "MySource" in meta_line
+        assert "14:30" in meta_line
+
+
+class TestRenderLine:
+    """Tests for render_line function."""
+
+    def test_empty_string(self):
+        """Empty string returns empty list."""
+        from engine.render import render_line
+
+        result = render_line("")
+        assert result == [""]
+
+    @pytest.mark.skip(reason="Requires real font/PIL setup")
+    def test_uses_default_font(self):
+        """Uses default font when none provided."""
+        from engine.render import render_line
+
+        with patch("engine.render.font") as mock_font:
+            mock_font.return_value = MagicMock()
+            mock_font.return_value.getbbox.return_value = (0, 0, 10, 10)
+            render_line("test")
+
+    def test_getbbox_returns_none(self):
+        """Handles None bbox gracefully."""
+        from engine.render import render_line
+
+        with patch("engine.render.font") as mock_font:
+            mock_font.return_value = MagicMock()
+            mock_font.return_value.getbbox.return_value = None
+            result = render_line("test")
+            assert result == [""]
+
+
+class TestBigWrap:
+    """Tests for big_wrap function."""
+
+    def test_empty_string(self):
+        """Empty string returns empty list."""
+        from engine.render import big_wrap
+
+        result = big_wrap("", 80)
+        assert result == []
+
+    @pytest.mark.skip(reason="Requires real font/PIL setup")
+    def test_single_word_fits(self):
+        """Single short word returns rendered."""
+        from engine.render import big_wrap
+
+        with patch("engine.render.font") as mock_font:
+            mock_font.return_value = MagicMock()
+            mock_font.return_value.getbbox.return_value = (0, 0, 10, 10)
+            result = big_wrap("test", 80)
+            assert len(result) > 0
--- a/tests/test_translate.py
+++ b/tests/test_translate.py
@@ -0,0 +1,115 @@
+"""
+Tests for engine.translate module.
+"""
+
+import json
+from unittest.mock import MagicMock, patch
+
+from engine.translate import (
+    _translate_cached,
+    detect_location_language,
+    translate_headline,
+)
+
+
+def clear_translate_cache():
+    """Clear the LRU cache between tests."""
+    _translate_cached.cache_clear()
+
+
+class TestDetectLocationLanguage:
+    """Tests for detect_location_language function."""
+
+    def test_returns_none_for_unknown_location(self):
+        """Returns None when no location pattern matches."""
+        result = detect_location_language("Breaking news about technology")
+        assert result is None
+
+    def test_detects_berlin(self):
+        """Detects Berlin location."""
+        result = detect_location_language("Berlin police arrest protesters")
+        assert result == "de"
+
+    def test_detects_paris(self):
+        """Detects Paris location."""
+        result = detect_location_language("Paris fashion week begins")
+        assert result == "fr"
+
+    def test_detects_tokyo(self):
+        """Detects Tokyo location."""
+        result = detect_location_language("Tokyo stocks rise")
+        assert result == "ja"
+
+    def test_detects_berlin_again(self):
+        """Detects Berlin location again."""
+        result = detect_location_language("Berlin marathon set to begin")
+        assert result == "de"
+
+    def test_case_insensitive(self):
+        """Detection is case insensitive."""
+        result = detect_location_language("BERLIN SUMMER FESTIVAL")
+        assert result == "de"
+
+    def test_returns_first_match(self):
+        """Returns first matching pattern."""
+        result = detect_location_language("Berlin in Paris for the event")
+        assert result == "de"
+
+
+class TestTranslateHeadline:
+    """Tests for translate_headline function."""
+
+    def test_returns_translated_text(self):
+        """Returns translated text from cache."""
+        clear_translate_cache()
+        with patch("engine.translate.translate_headline") as mock_fn:
+            mock_fn.return_value = "Translated title"
+            from engine.translate import translate_headline as th
+
+            result = th("Original title", "de")
+            assert result == "Translated title"
+
+    def test_uses_cached_result(self):
+        """Translation uses LRU cache."""
+        clear_translate_cache()
+        result1 = translate_headline("Test unique", "es")
+        result2 = translate_headline("Test unique", "es")
+        assert result1 == result2
+
+
+class TestTranslateCached:
+    """Tests for _translate_cached function."""
+
+    def test_translation_network_error(self):
+        """Network error returns original text."""
+        clear_translate_cache()
+        with patch("engine.translate.urllib.request.urlopen") as mock_urlopen:
+            mock_urlopen.side_effect = Exception("Network error")
+
+            result = _translate_cached("Hello world", "de")
+
+            assert result == "Hello world"
+
+    def test_translation_invalid_json(self):
+        """Invalid JSON returns original text."""
+        clear_translate_cache()
+        with patch("engine.translate.urllib.request.urlopen") as mock_urlopen:
+            mock_response = MagicMock()
+            mock_response.read.return_value = b"invalid json"
+            mock_urlopen.return_value = mock_response
+
+            result = _translate_cached("Hello", "de")
+
+            assert result == "Hello"
+
+    def test_translation_empty_response(self):
+        """Empty translation response returns original text."""
+        clear_translate_cache()
+        with patch("engine.translate.urllib.request.urlopen") as mock_urlopen:
+            mock_response = MagicMock()
+            mock_response.read.return_value = json.dumps([[[""], None, "de"], None])
+            mock_urlopen.return_value = mock_response
+
+            result = _translate_cached("Hello", "de")
+
+            assert result == "Hello"
--- a/tests/test_websocket.py
+++ b/tests/test_websocket.py
@@ -0,0 +1,161 @@
+"""
+Tests for engine.websocket_display module.
+"""
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from engine.websocket_display import WebSocketDisplay
+
+
+class TestWebSocketDisplayImport:
+    """Test that websocket module can be imported."""
+
+    def test_import_does_not_error(self):
+        """Module imports without error."""
+        from engine import websocket_display
+
+        assert websocket_display is not None
+
+
+class TestWebSocketDisplayInit:
+    """Tests for WebSocketDisplay initialization."""
+
+    def test_default_init(self):
+        """Default initialization sets correct defaults."""
+        with patch("engine.websocket_display.websockets", None):
+            display = WebSocketDisplay()
+            assert display.host == "0.0.0.0"
+            assert display.port == 8765
+            assert display.http_port == 8766
+            assert display.width == 80
+            assert display.height == 24
+
+    def test_custom_init(self):
+        """Custom initialization uses provided values."""
+        with patch("engine.websocket_display.websockets", None):
+            display = WebSocketDisplay(host="localhost", port=9000, http_port=9001)
+            assert display.host == "localhost"
+            assert display.port == 9000
+            assert display.http_port == 9001
+
+    def test_is_available_when_websockets_present(self):
+        """is_available returns True when websockets is available."""
+        pytest.importorskip("websockets")
+        display = WebSocketDisplay()
+        assert display.is_available() is True
+
+    @pytest.mark.skipif(
+        pytest.importorskip("websockets") is not None, reason="websockets is available"
+    )
+    def test_is_available_when_websockets_missing(self):
+        """is_available returns False when websockets is not available."""
+        display = WebSocketDisplay()
+        assert display.is_available() is False
+
+
+class TestWebSocketDisplayProtocol:
+    """Test that WebSocketDisplay satisfies Display protocol."""
+
+    def test_websocket_display_is_display(self):
+        """WebSocketDisplay satisfies Display protocol."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay()
+            assert hasattr(display, "init")
+            assert hasattr(display, "show")
+            assert hasattr(display, "clear")
+            assert hasattr(display, "cleanup")
+
+
+class TestWebSocketDisplayMethods:
+    """Tests for WebSocketDisplay methods."""
+
+    def test_init_stores_dimensions(self):
+        """init stores terminal dimensions."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay()
+            display.init(100, 40)
+            assert display.width == 100
+            assert display.height == 40
+
+    def test_client_count_initially_zero(self):
+        """client_count returns 0 when no clients connected."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay()
+            assert display.client_count() == 0
+
+    def test_get_ws_port(self):
+        """get_ws_port returns configured port."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay(port=9000)
+            assert display.get_ws_port() == 9000
+
+    def test_get_http_port(self):
+        """get_http_port returns configured port."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay(http_port=9001)
+            assert display.get_http_port() == 9001
+
+    def test_frame_delay_defaults_to_zero(self):
+        """get_frame_delay returns 0 by default."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay()
+            assert display.get_frame_delay() == 0.0
+
+    def test_set_frame_delay(self):
+        """set_frame_delay stores the value."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay()
+            display.set_frame_delay(0.05)
+            assert display.get_frame_delay() == 0.05
+
+
+class TestWebSocketDisplayCallbacks:
+    """Tests for WebSocketDisplay callback methods."""
+
+    def test_set_client_connected_callback(self):
+        """set_client_connected_callback stores callback."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay()
+            callback = MagicMock()
+            display.set_client_connected_callback(callback)
+            assert display._client_connected_callback is callback
+
+    def test_set_client_disconnected_callback(self):
+        """set_client_disconnected_callback stores callback."""
+        with patch("engine.websocket_display.websockets", MagicMock()):
+            display = WebSocketDisplay()
+            callback = MagicMock()
+            display.set_client_disconnected_callback(callback)
+            assert display._client_disconnected_callback is callback
+
+
+class TestWebSocketDisplayUnavailable:
+    """Tests when WebSocket support is unavailable."""
+
+    @pytest.mark.skipif(
+        pytest.importorskip("websockets") is not None, reason="websockets is available"
+    )
+    def test_start_server_noop_when_unavailable(self):
+        """start_server does nothing when websockets unavailable."""
+        display = WebSocketDisplay()
+        display.start_server()
+        assert display._server_thread is None
+
+    @pytest.mark.skipif(
+        pytest.importorskip("websockets") is not None, reason="websockets is available"
+    )
+    def test_start_http_server_noop_when_unavailable(self):
+        """start_http_server does nothing when websockets unavailable."""
+        display = WebSocketDisplay()
+        display.start_http_server()
+        assert display._http_thread is None
+
+    @pytest.mark.skipif(
+        pytest.importorskip("websockets") is not None, reason="websockets is available"
+    )
+    def test_show_noops_when_unavailable(self):
+        """show does nothing when websockets unavailable."""
+        display = WebSocketDisplay()
+        display.show(["line1", "line2"])
Author	SHA1	Message	Date
David Gwilliam	d7b044ceae	feat(display): add configurable multi-backend display system	2026-03-15 21:17:16 -07:00
David Gwilliam	ac1306373d	feat(websocket): add WebSocket display backend for browser client	2026-03-15 20:54:03 -07:00
David Gwilliam	2650f7245e	merge: effects_plugins	2026-03-15 19:20:53 -07:00
David Gwilliam	b1f2b9d2be	feat(daemon): add display abstraction and daemon mode with C&C	2026-03-15 19:20:47 -07:00
David Gwilliam	c08a7d3cb0	feat(cmdline): add command-line interface for mainline control	2026-03-15 19:20:47 -07:00
David Gwilliam	d5a3edba97	feat(effects): add plugin architecture with performance monitoring	2026-03-15 19:20:47 -07:00
David Gwilliam	fb35458718	merge: testability_modularization	2026-03-15 19:20:43 -07:00