feat(display-controller): round-robin between simultaneous live-priority games (#372)

_check_live_priority() was stateless first-match-wins: it returned the
first plugin in registration order with live content, and the post-dwell
hold pinned the carousel to it, so when two games were live at once (e.g.
a baseball game and a soccer match) the second never showed until the
first ended.

Add _collect_live_modes() (all currently-live modes, deduped, in
registration order) and give _check_live_priority an 'advance' flag. The
main rotation calls it with advance=True, which returns the live mode
after the one currently shown -- using current_display_mode as the cursor
-- so each dwell advances to the next live game and they take turns. The
Vegas coordinator and the vegas-active check keep the default
non-advancing peek (advance=False), so they only report whether any game
is live without spinning the cursor. should_rotate and _apply_live_priority
are unchanged; a single live game still holds as before.

Adds regression tests to TestDisplayControllerLivePriority.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/test.yml

@@ -0,0 +1,33 @@
+name: Tests
+
+on:
+  pull_request:
+  push:
+    branches: [main]
+
+jobs:
+  plugin-safety:
+    name: Plugin safety harness + unit tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          persist-credentials: false
+
+      - uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b # v5.3.0
+        with:
+          python-version: "3.12"
+          cache: pip
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt -r requirements-test.txt
+          pip install RGBMatrixEmulator
+
+      - name: Run harness + visual rendering tests
+        run: |
+          pytest --no-cov \
+            test/plugins/test_harness.py \
+            test/plugins/test_visual_rendering.py \
+            test/plugins/test_plugin_matrix.py

.gitignore

@@ -8,6 +8,7 @@ config/config_secrets.json
 config/config.json
 config/config.json.backup
 config/wifi_config.json
+config/uninstalled_plugins.json
 credentials.json
 token.pickle
 

docs/plugin-safety-harness.md

@@ -0,0 +1,136 @@
+# Plugin Safety Harness
+
+Renders a plugin across **every declared screen (mode)** and **a spread of
+matrix sizes**, and fails if any combination crashes, draws past the panel edge,
+or — for plugins that ship golden images — drifts visually. The goal: change a
+plugin without breaking a size or screen you didn't think to test.
+
+## Sizes: a sample, not a fixed list
+
+There is **no fixed set of supported panel sizes** — an RGB matrix build can be
+any width/height and configuration (square, rectangle, 2×2, 4×4, 8×2, long
+strips, tall stacks). Plugins are expected to read dimensions dynamically
+(`self.display_manager.matrix.width/height`) and lay themselves out
+accordingly, so a hardcoded coordinate or unscaled font shows up as a failure
+here.
+
+The harness therefore renders against a **representative sample** that spans the
+axes of variation (`DEFAULT_TEST_SIZES` in `src/plugin_system/testing/sizes.py`),
+not an authoritative list:
+
+Each module is 64×32; entries are real panel-grid arrangements (cols × rows):
+
+| Size    | Grid | Why it's in the sample                     |
+|---------|------|--------------------------------------------|
+| 64×32   | 1×1  | single panel — tightest common rectangle   |
+| 128×32  | 2×1  | the baseline most plugins are tuned for    |
+| 64×64   | 1×2  | stacked — tall-narrow centering            |
+| 128×64  | 2×2  | block — icon scaling / vertical centering  |
+| 256×32  | 4×1  | long strip — wide horizontal layout        |
+| 128×96  | 2×3  | tall — vertical overflow                   |
+| 256×128 | 4×4  | large block — both dimensions big at once  |
+
+**Override the sizes entirely** to test your actual hardware (or any shape):
+
+```bash
+# CLI — one-off:
+python scripts/check_plugin.py --plugin clock-simple --sizes 8x16,64x64,256x32
+
+# pytest — force every plugin onto your panel(s):
+LEDMATRIX_TEST_SIZES="8x16,128x128" pytest test/plugins/test_plugin_matrix.py
+
+# Per-plugin — declare the shapes a plugin targets in its test/harness.json:
+#   { "sizes": [[8, 16], [64, 64]] }
+```
+
+Precedence: `LEDMATRIX_TEST_SIZES` env (global) → per-plugin `harness.json`
+`sizes` → the default sample. Bounds checking adapts to whatever sizes a run
+uses — the backing canvas is padded out to the **largest** panel in the run, so
+a coordinate meant for a big build is still caught when rendering a small one.
+
+## Quick start
+
+```bash
+# Functional + bounds check across all sizes/screens:
+python scripts/check_plugin.py --plugin clock-simple
+
+# Every discovered plugin:
+python scripts/check_plugin.py --all
+
+# Dump PNGs to eyeball each size/screen:
+python scripts/check_plugin.py --plugin ledmatrix-weather --out-dir /tmp/preview
+```
+
+Exit code is non-zero if any `(plugin, size, screen)` fails. Plugins are
+discovered in `plugin-repos/` and `plugins/` (override with `--plugin-dir`).
+
+## What it checks (Phase 1 — always on)
+
+1. **Loads** and builds its mode list.
+2. **Renders every screen** at every size without raising. `update()` may fail
+   (no network in CI) and is tolerated; a crash in `display()` is a failure —
+   `display()` must handle the no-data state.
+3. **Bounds**: nothing is drawn past the right/bottom edge. Implemented by
+   `BoundsCheckingDisplayManager`, which backs the declared panel with an
+   oversized canvas and flags any pixels that land in the margin. (Left/top
+   overflow at negative coordinates and BDF text are not flagged — golden images
+   cover those.)
+
+## Golden images (Phase 2 — opt-in per plugin)
+
+A plugin opts in by committing reference PNGs and (usually) a small harness spec:
+
+```
+plugins/<id>/test/harness.json          # how to render deterministically
+plugins/<id>/test/fixtures/mock.json     # optional cached data
+plugins/<id>/test/golden/<WxH>/<mode>.png
+```
+
+`test/harness.json` keys (all optional):
+
+```json
+{
+  "config":      { "timezone": "UTC" },
+  "mock_data":   "fixtures/mock.json",
+  "freeze_time": "2025-08-01 15:25:00",
+  "skip_update": false,
+  "sizes":       [[128, 32], [128, 64]]
+}
+```
+
+Generate / refresh goldens after an intentional visual change, then review the
+diff before committing:
+
+```bash
+python scripts/check_plugin.py --plugin clock-simple --update-golden \
+  --config '{"timezone":"UTC"}' --freeze-time "2025-08-01 15:25:00"
+```
+
+Comparison is exact by default (`compare_images` in `harness.py` accepts a
+tolerance for known anti-aliasing noise). Determinism requires a pinned Pillow
+and the bundled fonts — keep both stable when regenerating goldens.
+
+## Tests & CI
+
+- `test/plugins/test_harness.py` — unit tests for bounds detection, image
+  comparison, and mode enumeration (run anywhere).
+- `test/plugins/test_plugin_matrix.py` — parametrized over discovered plugins ×
+  sizes × screens; honors each plugin's `test/harness.json` and goldens. Skips
+  when no plugins are present (e.g. a fresh core checkout); set
+  `LEDMATRIX_REQUIRE_PLUGINS=1` in a pipeline where plugins must be present to
+  turn an empty discovery into a hard failure instead. Point it at the monorepo
+  with `LEDMATRIX_PLUGINS_DIR=/path/to/ledmatrix-plugins/plugins`.
+- `.github/workflows/test.yml` — runs the harness + visual tests on every PR.
+
+The plugin monorepo has its own `Plugin Safety` workflow that runs this harness
+against changed plugins on every PR.
+
+## Developer workflow
+
+1. Change the plugin on a branch.
+2. `python scripts/check_plugin.py --plugin <id> --out-dir /tmp/preview` and
+   eyeball the PNGs.
+3. Intentional visual change? `--update-golden`, review diffs, commit goldens.
+4. (Monorepo) bump `manifest.json` version and let the pre-commit hook sync
+   `plugins.json`.
+5. Push — CI re-runs the harness across all sizes and gates the PR.

first_time_install.sh

@@ -15,8 +15,8 @@ on_error() {
     echo "✗ An error occurred during: $CURRENT_STEP (line $line_no, exit $exit_code)" >&2
     if [ -n "${LOG_FILE:-}" ]; then
         echo "See the log for details: $LOG_FILE" >&2
-        echo "-- Last 50 lines from log --" >&2
+        echo "-- Last 100 lines from log --" >&2
-        tail -n 50 "$LOG_FILE" >&2 || true
+        tail -n 100 "$LOG_FILE" >&2 || true
     fi
     echo "\nCommon fixes:" >&2
     echo "- Ensure the Pi is online (try: ping -c1 8.8.8.8)." >&2
@@ -202,8 +202,33 @@ retry() {
     done
 }
 
-apt_update() { retry apt update; }
+# Wait for another apt/dpkg process (commonly unattended-upgrades running
-apt_install() { retry apt install -y "$@"; }
+# shortly after first boot) to release its lock before we try apt ourselves.
+# Without this, apt_update/apt_install can fail outright in the first couple
+# minutes after a fresh Pi OS boot with a generic "Command failed after 3
+# attempts" error.
+wait_for_apt_lock() {
+    command -v flock >/dev/null 2>&1 || return 0
+    local lock_file="/var/lib/dpkg/lock-frontend"
+    local max_wait=180
+    local waited=0
+    local printed=0
+    while ! flock -n "$lock_file" -c true 2>/dev/null; do
+        if [ "$printed" -eq 0 ]; then
+            echo "⚠ Waiting for another apt/dpkg process to finish (e.g. unattended-upgrades on first boot)..."
+            printed=1
+        fi
+        if [ "$waited" -ge "$max_wait" ]; then
+            echo "⚠ Still waiting after ${max_wait}s; proceeding anyway."
+            break
+        fi
+        sleep 5
+        waited=$((waited+5))
+    done
+}
+
+apt_update() { wait_for_apt_lock; retry apt update; }
+apt_install() { wait_for_apt_lock; retry apt install -y "$@"; }
 apt_remove() { apt-get remove -y "$@" || true; }
 
 check_network() {
@@ -222,6 +247,22 @@ check_network() {
     exit 1
 }
 
+check_disk_space() {
+    command -v df >/dev/null 2>&1 || return 0
+    local available_mb
+    available_mb=$(df -m "$PROJECT_ROOT_DIR" | awk 'NR==2{print $4}')
+    available_mb=${available_mb:-0}
+    if [ "$available_mb" -lt 500 ]; then
+        echo "✗ ERROR: Insufficient disk space: ${available_mb}MB available (need at least 500MB)"
+        echo "  Free up space first, e.g.: sudo apt clean && sudo apt autoremove"
+        exit 1
+    elif [ "$available_mb" -lt 1024 ]; then
+        echo "⚠ Limited disk space: ${available_mb}MB available (recommend at least 1GB for the rpi-rgb-led-matrix build in Step 6)"
+    else
+        echo "✓ Disk space sufficient: ${available_mb}MB available"
+    fi
+}
+
 echo ""
 echo "This script will perform the following steps:"
 echo "1. Install system dependencies"
@@ -271,8 +312,9 @@ CURRENT_STEP="Install system dependencies"
 echo "Step 1: Installing system dependencies..."
 echo "----------------------------------------"
 
-# Ensure network is available before APT operations
+# Pre-flight checks before APT operations
 check_network
+check_disk_space
 
 # Update package list
 apt_update
@@ -822,14 +864,14 @@ else
         # Try to initialize submodule if .gitmodules exists
         if [ -f "$PROJECT_ROOT_DIR/.gitmodules" ] && grep -q "rpi-rgb-led-matrix" "$PROJECT_ROOT_DIR/.gitmodules"; then
             echo "Initializing rpi-rgb-led-matrix submodule..."
-            if ! git submodule update --init --recursive rpi-rgb-led-matrix-master 2>&1; then
+            if ! retry git submodule update --init --recursive rpi-rgb-led-matrix-master; then
                 echo "⚠ Submodule init failed, cloning directly from GitHub..."
-                git clone https://github.com/hzeller/rpi-rgb-led-matrix.git rpi-rgb-led-matrix-master
+                retry git clone https://github.com/hzeller/rpi-rgb-led-matrix.git rpi-rgb-led-matrix-master
             fi
         else
             # Fallback: clone directly if submodule not configured
             echo "Submodule not configured, cloning directly from GitHub..."
-            git clone https://github.com/hzeller/rpi-rgb-led-matrix.git rpi-rgb-led-matrix-master
+            retry git clone https://github.com/hzeller/rpi-rgb-led-matrix.git rpi-rgb-led-matrix-master
         fi
     fi
     
@@ -841,9 +883,9 @@ else
             cd "$PROJECT_ROOT_DIR"
             rm -rf rpi-rgb-led-matrix-master
             if [ -f "$PROJECT_ROOT_DIR/.gitmodules" ] && grep -q "rpi-rgb-led-matrix" "$PROJECT_ROOT_DIR/.gitmodules"; then
-                git submodule update --init --recursive rpi-rgb-led-matrix-master
+                retry git submodule update --init --recursive rpi-rgb-led-matrix-master
             else
-                git clone https://github.com/hzeller/rpi-rgb-led-matrix.git rpi-rgb-led-matrix-master
+                retry git clone https://github.com/hzeller/rpi-rgb-led-matrix.git rpi-rgb-led-matrix-master
             fi
         fi
 
@@ -851,13 +893,24 @@ else
         echo "Installing rpi-rgb-led-matrix Python package (scikit-build-core + cmake)..."
         echo "  Build deps required: python-dev-is-python3 cmake"
         echo "  This compiles C++ — may take 2-5 minutes on Pi 4/5..."
-        if ! python3 -m pip install --break-system-packages .; then
+        BUILD_OUTPUT=$(mktemp)
+        BUILD_SUCCESS=false
+        if python3 -m pip install --break-system-packages . > "$BUILD_OUTPUT" 2>&1; then
+            BUILD_SUCCESS=true
+        fi
+        cat "$BUILD_OUTPUT" >> "$LOG_FILE"
+        if [ "$BUILD_SUCCESS" != true ]; then
             echo "✗ Failed to install rpi-rgb-led-matrix Python package"
             echo "  Ensure build tools are installed:"
             echo "  sudo apt install -y python-dev-is-python3 cmake build-essential"
+            echo ""
+            echo "-- Last 50 lines of build output --"
+            tail -n 50 "$BUILD_OUTPUT"
+            rm -f "$BUILD_OUTPUT"
             popd >/dev/null
             exit 1
         fi
+        rm -f "$BUILD_OUTPUT"
         popd >/dev/null
     else
         echo "✗ rpi-rgb-led-matrix-master directory not found at $PROJECT_ROOT_DIR"
@@ -912,7 +965,9 @@ else
     # Try to install dependencies using the smart installer if available
     if [ -f "$PROJECT_ROOT_DIR/scripts/install_dependencies_apt.py" ]; then
         echo "Using smart dependency installer..."
-        python3 "$PROJECT_ROOT_DIR/scripts/install_dependencies_apt.py"
+        # -u: unbuffered stdout/stderr so output is captured in $LOG_FILE in
+        # real time and in order relative to this script's own echo statements
+        python3 -u "$PROJECT_ROOT_DIR/scripts/install_dependencies_apt.py"
     else
         echo "Using pip to install dependencies..."
         if [ -f "$PROJECT_ROOT_DIR/requirements_web_v2.txt" ]; then

requirements-test.txt

@@ -0,0 +1,9 @@
+# Test-only dependencies for the plugin safety harness and pytest suite.
+# Install alongside requirements.txt:  pip install -r requirements.txt -r requirements-test.txt
+#
+# pytest, pytest-cov, pytest-mock, and jsonschema are already pinned (with
+# major-version caps) in requirements.txt, so they are intentionally NOT
+# repeated here — re-pinning pytest to <9 collided with requirements.txt's
+# pytest>=9.0.3,<10 and made the two files impossible to install together.
+# Only declare what requirements.txt doesn't already provide.
+freezegun>=1.2,<2        # deterministic time for golden-image tests

scripts/check_plugin.py

@@ -0,0 +1,232 @@
+#!/usr/bin/env python3
+"""
+Plugin safety checker.
+
+Renders a plugin across every declared screen (mode) and every supported matrix
+size, and fails if any screen crashes, overflows the panel, or (for plugins with
+committed golden images) drifts visually.
+
+Usage:
+    # Functional + bounds check across all sizes/modes:
+    python scripts/check_plugin.py --plugin clock-simple
+
+    # Every discovered plugin:
+    python scripts/check_plugin.py --all
+
+    # Dump PNGs for each size/mode so you can eyeball them:
+    python scripts/check_plugin.py --plugin ledmatrix-weather --out-dir /tmp/preview
+
+    # Refresh committed golden images after an intentional visual change:
+    python scripts/check_plugin.py --plugin clock-simple --update-golden \
+        --mock-data plugins/clock-simple/test/fixtures/mock.json
+
+Exit code is non-zero if any (plugin, size, mode) fails.
+"""
+
+import argparse
+import json
+import os
+import sys
+from pathlib import Path
+from typing import Dict, List, Optional
+
+PROJECT_ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(PROJECT_ROOT))
+
+os.environ['EMULATOR'] = 'true'
+
+from src.logging_config import get_logger  # noqa: E402
+from src.plugin_system.testing.loading import (  # noqa: E402
+    find_plugin_dir, load_config_defaults, load_harness_spec,
+)
+from src.plugin_system.testing.harness import (  # noqa: E402
+    RenderResult, render_plugin_matrix, compare_to_goldens, write_goldens,
+)
+from src.plugin_system.testing.sizes import (  # noqa: E402
+    parse_size_token, resolve_test_sizes, safe_mode_filename, size_label,
+)
+
+logger = get_logger("[Check Plugin]")
+
+DEFAULT_SEARCH_DIRS = [
+    str(PROJECT_ROOT / 'plugins'),
+    str(PROJECT_ROOT / 'plugin-repos'),
+]
+
+
+def discover_plugins(search_dirs: List[str]) -> List[str]:
+    """All plugin ids found across the search dirs (dirs containing manifest.json)."""
+    found = []
+    for d in search_dirs:
+        base = Path(d)
+        if not base.exists():
+            continue
+        for child in sorted(base.iterdir()):
+            if (child / 'manifest.json').exists() and child.name not in found:
+                found.append(child.name)
+    return found
+
+
+def parse_sizes(spec: Optional[str]):
+    if not spec:
+        return None
+    sizes = []
+    for token in spec.split(','):
+        if not token.strip():
+            continue
+        try:
+            sizes.append(parse_size_token(token))
+        except ValueError as exc:
+            raise SystemExit(str(exc)) from exc
+    return sizes
+
+
+def check_one(plugin_id: str, search_dirs: List[str], sizes, mock_data: Dict,
+              config: Dict, run_update: bool, out_dir: Optional[Path],
+              update_golden: bool, golden_dir_override: Optional[Path],
+              freeze_time: Optional[str]) -> List[RenderResult]:
+    plugin_dir = find_plugin_dir(plugin_id, search_dirs)
+    if not plugin_dir:
+        logger.error("Plugin '%s' not found in: %s", plugin_id, search_dirs)
+        return [RenderResult(plugin_id, 0, 0, "<not-found>", error="plugin directory not found")]
+
+    # Per-plugin test/harness.json holds the deterministic settings the committed
+    # goldens were generated with (config, mock data, frozen time, sizes). Load
+    # them so the CLI/CI render reproduces the golden the same way the pytest
+    # matrix path does; explicit CLI flags still override the file.
+    spec = load_harness_spec(plugin_dir)
+
+    # config_schema defaults (real-install behavior), then harness.json config,
+    # then CLI --config — most specific wins.
+    full_config = {"enabled": True}
+    full_config.update(load_config_defaults(plugin_dir))
+    full_config.update(spec.get("config", {}))
+    full_config.update(config)
+
+    # Precedence: CLI flag > LEDMATRIX_TEST_SIZES env > harness.json > default.
+    effective_sizes = sizes if sizes else resolve_test_sizes(spec.get("sizes"))
+    # CLI value wins when provided, else fall back to the harness.json setting.
+    effective_mock_data = mock_data or spec.get("mock_data_contents", {})
+    effective_freeze = freeze_time or spec.get("freeze_time")
+    effective_run_update = run_update and not spec.get("skip_update", False)
+
+    results = render_plugin_matrix(
+        plugin_id=plugin_id, plugin_dir=plugin_dir, config=full_config,
+        mock_data=effective_mock_data, sizes=effective_sizes,
+        run_update=effective_run_update, freeze_time=effective_freeze,
+    )
+
+    golden_dir = golden_dir_override or (plugin_dir / 'test' / 'golden')
+    if update_golden:
+        written = write_goldens(results, golden_dir)
+        logger.info("Wrote %d golden image(s) for %s to %s", written, plugin_id, golden_dir)
+    else:
+        compare_to_goldens(results, golden_dir)
+
+    if out_dir:
+        for r in results:
+            if r.image is None:
+                continue
+            dest = out_dir / plugin_id / size_label(r.width, r.height)
+            dest.mkdir(parents=True, exist_ok=True)
+            r.image.save(dest / f"{safe_mode_filename(r.mode)}.png", format="PNG")
+
+    return results
+
+
+def print_report(all_results: Dict[str, List[RenderResult]]) -> bool:
+    """Print a per-plugin grid. Returns True if everything passed."""
+    everything_ok = True
+    for plugin_id, results in all_results.items():
+        print(f"\n=== {plugin_id} ===")
+        for r in results:
+            if r.ok:
+                status = "PASS"
+                detail = ""
+                if r.golden_checked:
+                    detail = " (golden ✓)"
+                if r.update_error is not None:
+                    detail += f" (update warn: {r.update_error})"
+            else:
+                everything_ok = False
+                if r.error is not None:
+                    status, detail = "FAIL", f" error={r.error}"
+                elif r.overflow is not None:
+                    status, detail = "FAIL", f" overflow bbox={r.overflow}"
+                elif r.golden_ok is False:
+                    status = "FAIL"
+                    detail = f" golden drift: {r.golden_diff_pixels}px (max Δ={r.golden_max_delta})"
+                else:
+                    status, detail = "FAIL", ""
+            print(f"  [{status}] {r.size_label:>7}  {r.mode}{detail}")
+    print()
+    return everything_ok
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description="Check a plugin renders safely across sizes & screens")
+    group = parser.add_mutually_exclusive_group(required=True)
+    group.add_argument('--plugin', '-p', help='Plugin id to check')
+    group.add_argument('--all', action='store_true', help='Check every discovered plugin')
+    parser.add_argument('--plugin-dir', '-d', default=None, help='Directory to search for plugins')
+    parser.add_argument('--sizes', default=None, help='Comma-separated WxH list (default: all supported)')
+    parser.add_argument('--config', '-c', default='{}', help='Plugin config overrides as JSON')
+    parser.add_argument('--mock-data', '-m', default=None, help='Path to JSON file with mock cache data')
+    parser.add_argument('--out-dir', '-o', default=None, help='Also dump rendered PNGs here')
+    parser.add_argument('--skip-update', action='store_true', help='Skip calling update()')
+    parser.add_argument('--update-golden', action='store_true', help='Write/refresh golden images')
+    parser.add_argument('--golden-dir', default=None, help='Override golden dir (default: <plugin>/test/golden)')
+    parser.add_argument('--freeze-time', default=None,
+                        help='Freeze wall clock, e.g. "2025-08-01 15:25:00" (for time-dependent plugins)')
+    args = parser.parse_args()
+
+    search_dirs = [args.plugin_dir] if args.plugin_dir else DEFAULT_SEARCH_DIRS
+    sizes = parse_sizes(args.sizes)
+
+    try:
+        config = json.loads(args.config)
+    except json.JSONDecodeError as e:
+        logger.error("Invalid --config JSON: %s", e)
+        return 2
+    if not isinstance(config, dict):
+        logger.error("--config must be a JSON object, got %s", type(config).__name__)
+        return 2
+
+    mock_data = {}
+    if args.mock_data:
+        mock_path = Path(args.mock_data)
+        if not mock_path.exists():
+            logger.error("Mock data file not found: %s", args.mock_data)
+            return 2
+        with open(mock_path) as f:
+            mock_data = json.load(f)
+        if not isinstance(mock_data, dict):
+            logger.error("--mock-data must be a JSON object (key -> cache value), got %s",
+                         type(mock_data).__name__)
+            return 2
+
+    plugin_ids = discover_plugins(search_dirs) if args.all else [args.plugin]
+    if not plugin_ids:
+        logger.error("No plugins found in: %s", search_dirs)
+        return 2
+
+    out_dir = Path(args.out_dir) if args.out_dir else None
+    golden_dir_override = Path(args.golden_dir) if args.golden_dir else None
+
+    all_results: Dict[str, List[RenderResult]] = {}
+    for plugin_id in plugin_ids:
+        all_results[plugin_id] = check_one(
+            plugin_id=plugin_id, search_dirs=search_dirs, sizes=sizes,
+            mock_data=mock_data, config=config, run_update=not args.skip_update,
+            out_dir=out_dir, update_golden=args.update_golden,
+            golden_dir_override=golden_dir_override, freeze_time=args.freeze_time,
+        )
+
+    # When refreshing goldens we skip drift comparison, but a crash or overflow
+    # still means the plugin is broken — never let --update-golden mask that.
+    ok = print_report(all_results)
+    return 0 if ok else 1
+
+
+if __name__ == '__main__':
+    sys.exit(main())

scripts/install/one-shot-install.sh

@@ -340,8 +340,13 @@ main() {
     echo ""
     
     # Execute with proper error handling and non-interactive mode
-    # Temporarily disable errexit to capture exit code instead of exiting immediately
+    # Temporarily disable errexit AND the ERR trap to capture exit code instead of
+    # exiting immediately. `set +e` alone does not suppress the ERR trap, so without
+    # `trap '' ERR` a non-zero exit from first_time_install.sh would trigger on_error
+    # here with the generic "Main installation" message instead of the detailed
+    # if/else handling below.
     set +e
+    trap '' ERR
 
     # Check /tmp permissions - only fix if actually wrong (common in automated scenarios)
     # When running manually, /tmp usually has correct permissions (1777)
@@ -370,6 +375,7 @@ main() {
         sudo -E env TMPDIR=/tmp LEDMATRIX_ASSUME_YES=1 bash ./first_time_install.sh -y </dev/null
     fi
     INSTALL_EXIT_CODE=$?
+    trap 'on_error $LINENO' ERR  # Re-enable ERR trap
     set -e  # Re-enable errexit
     
     if [ $INSTALL_EXIT_CODE -eq 0 ]; then

scripts/install_dependencies_apt.py

@@ -6,46 +6,67 @@ then falls back to pip with --break-system-packages
 
 import subprocess
 import sys
+import tempfile
 import warnings
+from collections import deque
 from pathlib import Path
 
+# How many trailing lines of a failed command's output to keep for the
+# end-of-run failure summary. Keeps the root cause near the end of the log,
+# which is where first_time_install.sh's error handler tails from.
+ERROR_TAIL_LINES = 15
+
+
+def _run(cmd):
+    """Run a command, streaming combined stdout/stderr to a temp file.
+
+    Returns (success, output) instead of raising, so callers can report
+    *why* a command failed rather than just that it failed. `output` is
+    bounded to the last ERROR_TAIL_LINES lines so failures from very
+    chatty commands (e.g. pip build logs) don't get buffered in memory.
+    """
+    with tempfile.TemporaryFile(mode='w+b') as f:
+        result = subprocess.run(cmd, stdout=f, stderr=subprocess.STDOUT)  # nosec B603 B607 - hardcoded apt/pip args  # nosemgrep
+        f.seek(0)
+        # Stream line-by-line so only the last ERROR_TAIL_LINES are ever held
+        # in memory, regardless of how much output the command produced.
+        tail = deque(
+            (line.decode('utf-8', errors='replace').rstrip('\n') for line in f),
+            maxlen=ERROR_TAIL_LINES,
+        )
+    return result.returncode == 0, '\n'.join(tail)
+
+
 def install_via_apt(package_name):
-    """Try to install a package via apt."""
+    """Try to install a package via apt. Returns (success, output)."""
-    try:
+    # Map pip package names to apt package names
-        # Map pip package names to apt package names
+    apt_package_map = {
-        apt_package_map = {
+        'flask': 'python3-flask',
-            'flask': 'python3-flask',
+        'PIL': 'python3-pil',
-            'PIL': 'python3-pil',
+        'freetype': 'python3-freetype',
-            'freetype': 'python3-freetype',
+        'psutil': 'python3-psutil',
-            'psutil': 'python3-psutil',
+        'werkzeug': 'python3-werkzeug',
-            'werkzeug': 'python3-werkzeug',
+        'numpy': 'python3-numpy',
-            'numpy': 'python3-numpy',
+        'requests': 'python3-requests',
-            'requests': 'python3-requests',
+        'python-dateutil': 'python3-dateutil',
-            'python-dateutil': 'python3-dateutil',
+        'pytz': 'python3-tz',
-            'pytz': 'python3-tz',
+        'geopy': 'python3-geopy',
-            'geopy': 'python3-geopy',
+        'unidecode': 'python3-unidecode',
-            'unidecode': 'python3-unidecode',
+        'websockets': 'python3-websockets',
-            'websockets': 'python3-websockets',
+        'websocket-client': 'python3-websocket-client'
-            'websocket-client': 'python3-websocket-client'
+    }
-        }
 
-        apt_package = apt_package_map.get(package_name, f'python3-{package_name}')
+    apt_package = apt_package_map.get(package_name, f'python3-{package_name}')
-        
-        print(f"Trying to install {apt_package} via apt...")
-        subprocess.check_call([
-            'sudo', 'apt', 'update'
-        ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
-        
-        subprocess.check_call([
-            'sudo', 'apt', 'install', '-y', apt_package
-        ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
 
+    print(f"Trying to install {apt_package} via apt...")
+    success, output = _run(['sudo', 'apt', 'install', '-y', apt_package])
+    if success:
         print(f"Successfully installed {apt_package} via apt")
-        return True
+        return True, ""
+
+    print(f"Failed to install {apt_package} via apt, will try pip")
+    return False, output
 
-    except subprocess.CalledProcessError:
-        print(f"Failed to install {package_name} via apt, will try pip")
-        return False
 
 def install_via_pip(package_name):
     """Install a package via pip with --break-system-packages and --prefer-binary.
@@ -54,34 +75,73 @@ def install_via_pip(package_name):
     Debian/Ubuntu-based systems without a virtual environment.
     --prefer-binary prefers pre-built wheels over source distributions to avoid
     exhausting /tmp space during compilation.
+    --ignore-installed stops pip from trying to *uninstall* packages that were
+    installed by apt (e.g. python3-requests). Those Debian packages ship no
+    pip RECORD file, so an uninstall attempt fails with "uninstall-no-record-file"
+    and aborts the whole install. With --ignore-installed, pip lays the new
+    version down in /usr/local where it shadows the apt copy instead of removing
+    it. This matters when a pip dependency (google-api-python-client pulls a
+    newer requests) needs to upgrade an apt-managed package.
+
+    Returns (success, output).
     """
-    try:
+    print(f"Installing {package_name} via pip...")
-        print(f"Installing {package_name} via pip...")
+    success, output = _run([
-        subprocess.check_call([
+        sys.executable, '-m', 'pip', 'install',
-            sys.executable, '-m', 'pip', 'install', '--break-system-packages', '--prefer-binary', package_name
+        '--break-system-packages', '--prefer-binary', '--ignore-installed', package_name
-        ])
+    ])
+    if success:
         print(f"Successfully installed {package_name} via pip")
-        return True
+        return True, ""
-    except subprocess.CalledProcessError as e:
+
-        print(f"Failed to install {package_name} via pip: {e}")
+    print(f"Failed to install {package_name} via pip (see failure summary at end of log)")
-        return False
+    return False, output
+
+
+# Distribution (pip/apt) names whose importable module name differs.
+IMPORT_NAME_MAP = {
+    'python-dateutil': 'dateutil',
+    'websocket-client': 'websocket',
+}
+
 
 def check_package_installed(package_name):
     """Check if a package is already installed."""
+    import_name = IMPORT_NAME_MAP.get(package_name, package_name)
     # Suppress deprecation warnings when checking if packages are installed
     # (we're just checking, not using them)
     with warnings.catch_warnings():
         warnings.filterwarnings('ignore', category=DeprecationWarning)
         try:
-            __import__(package_name)
+            __import__(import_name)
             return True
         except ImportError:
             return False
 
+
+def print_failure_summary(failed_packages, failure_details):
+    print("\n" + "=" * 60)
+    print("DEPENDENCY INSTALLATION FAILURES - DETAILS")
+    print("=" * 60)
+    for package in failed_packages:
+        print(f"\nPackage: {package}")
+        print("-" * 40)
+        output = failure_details.get(package, "").strip()
+        if not output:
+            print("  (no output captured)")
+            continue
+        for line in output.splitlines()[-ERROR_TAIL_LINES:]:
+            print(f"  {line}")
+    print("=" * 60)
+
+
 def main():
     """Main installation function."""
     print("Installing dependencies for LED Matrix Web Interface V2...")
 
+    print("Refreshing apt package index...")
+    _run(['sudo', 'apt', 'update'])  # best-effort; individual installs surface their own errors
+
     # List of required packages
     required_packages = [
         'flask',
@@ -100,6 +160,7 @@ def main():
     ]
 
     failed_packages = []
+    failure_details = {}
 
     for package in required_packages:
         if check_package_installed(package):
@@ -107,9 +168,12 @@ def main():
             continue
 
         # Try apt first, then pip
-        if not install_via_apt(package):
+        ok, apt_output = install_via_apt(package)
-            if not install_via_pip(package):
+        if not ok:
+            ok, pip_output = install_via_pip(package)
+            if not ok:
                 failed_packages.append(package)
+                failure_details[package] = pip_output or apt_output
 
     # Install packages that don't have apt equivalents
     special_packages = [
@@ -124,8 +188,10 @@ def main():
     ]
 
     for package in special_packages:
-        if not install_via_pip(package):
+        ok, pip_output = install_via_pip(package)
+        if not ok:
             failed_packages.append(package)
+            failure_details[package] = pip_output
 
     # Install rgbmatrix module from local source (optional - may already be installed in Step 6)
     # Check if already installed first
@@ -133,36 +199,36 @@ def main():
         print("rgbmatrix module already installed, skipping...")
     else:
         print("Installing rgbmatrix module from local source...")
-        try:
+        # Get project root (parent of scripts directory)
-            # Get project root (parent of scripts directory)
+        PROJECT_ROOT = Path(__file__).parent.parent
-            PROJECT_ROOT = Path(__file__).parent.parent
+        rgbmatrix_path = PROJECT_ROOT / 'rpi-rgb-led-matrix-master' / 'bindings' / 'python'
-            rgbmatrix_path = PROJECT_ROOT / 'rpi-rgb-led-matrix-master' / 'bindings' / 'python'
+        if rgbmatrix_path.exists():
-            if rgbmatrix_path.exists():
+            # Check if the module has been built (look for setup.py)
-                # Check if the module has been built (look for setup.py)
+            setup_py = rgbmatrix_path / 'setup.py'
-                setup_py = rgbmatrix_path / 'setup.py'
+            if setup_py.exists():
-                if setup_py.exists():
+                # Try installing - use regular install, not editable mode
-                    # Try installing - use regular install, not editable mode
+                # This is optional for web interface and should already be installed in Step 6
-                    # This is optional for web interface and should already be installed in Step 6
+                ok, output = _run([sys.executable, '-m', 'pip', 'install', '--break-system-packages', '--ignore-installed', str(rgbmatrix_path)])
-                    subprocess.check_call([
+                if ok:
-                        sys.executable, '-m', 'pip', 'install', '--break-system-packages', str(rgbmatrix_path)
-                    ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
                     print("rgbmatrix module installed successfully")
                 else:
-                    print("Warning: rgbmatrix setup.py not found, module may need to be built first")
+                    # Don't fail the whole installation - rgbmatrix is optional for web interface
-                    print("  This is normal if Step 6 hasn't completed yet.")
+                    # and should be installed in Step 6 of first_time_install.sh
+                    print("Warning: Failed to install rgbmatrix module:")
+                    for line in output.strip().splitlines()[-ERROR_TAIL_LINES:]:
+                        print(f"  {line}")
+                    print("  This is normal if rgbmatrix hasn't been built yet (Step 6).")
+                    print("  The web interface will work without it.")
             else:
-                print("Warning: rgbmatrix source not found (this is normal if Step 6 hasn't run yet)")
+                print("Warning: rgbmatrix setup.py not found, module may need to be built first")
-        except subprocess.CalledProcessError as e:
+                print("  This is normal if Step 6 hasn't completed yet.")
-            # Don't fail the whole installation - rgbmatrix is optional for web interface
+        else:
-            # and should be installed in Step 6 of first_time_install.sh
+            print("Warning: rgbmatrix source not found (this is normal if Step 6 hasn't run yet)")
-            print(f"Warning: Failed to install rgbmatrix module: {e}")
-            print("  This is normal if rgbmatrix hasn't been built yet (Step 6).")
-            print("  The web interface will work without it.")
-            # Don't add to failed_packages since it's optional
 
     if failed_packages:
         print(f"\nFailed to install the following packages: {failed_packages}")
         print("You may need to install them manually or check your system configuration.")
+        print_failure_summary(failed_packages, failure_details)
         return False
     else:
         print("\nAll dependencies installed successfully!")

scripts/render_plugin.py

@@ -17,7 +17,6 @@ import os
 import json
 import argparse
 from pathlib import Path
-from typing import Any, Dict, Optional, Sequence, Union
 
 # Add project root to path
 PROJECT_ROOT = Path(__file__).resolve().parent.parent
@@ -28,49 +27,15 @@ os.environ['EMULATOR'] = 'true'
 
 # Import logger after path setup so src.logging_config is importable
 from src.logging_config import get_logger  # noqa: E402
+from src.plugin_system.testing.loading import (  # noqa: E402
+    find_plugin_dir, load_manifest, load_config_defaults,
+)
 logger = get_logger("[Render Plugin]")
 
 MIN_DIMENSION = 1
 MAX_DIMENSION = 512
 
 
-def find_plugin_dir(plugin_id: str, search_dirs: Sequence[Union[str, Path]]) -> Optional[Path]:
-    """Find a plugin directory by searching multiple paths."""
-    from src.plugin_system.plugin_loader import PluginLoader
-    loader = PluginLoader()
-    for search_dir in search_dirs:
-        search_path = Path(search_dir)
-        if not search_path.exists():
-            continue
-        result = loader.find_plugin_directory(plugin_id, search_path)
-        if result:
-            return Path(result)
-    return None
-
-
-def load_manifest(plugin_dir: Path) -> Dict[str, Any]:
-    """Load and return manifest.json from plugin directory."""
-    manifest_path = plugin_dir / 'manifest.json'
-    if not manifest_path.exists():
-        raise FileNotFoundError(f"No manifest.json in {plugin_dir}")
-    with open(manifest_path, 'r') as f:
-        return json.load(f)
-
-
-def load_config_defaults(plugin_dir: Path) -> Dict[str, Any]:
-    """Extract default values from config_schema.json."""
-    schema_path = plugin_dir / 'config_schema.json'
-    if not schema_path.exists():
-        return {}
-    with open(schema_path, 'r') as f:
-        schema = json.load(f)
-    defaults: Dict[str, Any] = {}
-    for key, prop in schema.get('properties', {}).items():
-        if 'default' in prop:
-            defaults[key] = prop['default']
-    return defaults
-
-
 def main() -> int:
     """Load a plugin, call update() + display(), and save the result as a PNG image."""
     parser = argparse.ArgumentParser(description='Render a plugin display to a PNG image')

src/display_controller.py

@@ -1505,30 +1505,68 @@ class DisplayController:
             logger.info("Live priority ended - resuming rotation at %s", self.current_display_mode)
             self._live_resume_index = None
 
-    def _check_live_priority(self):
+    def _collect_live_modes(self):
-        """
+        """Return every currently live-priority mode, in registration order.
-        Check all plugins for live priority content.
+
-        Returns the mode that should be displayed if live content is found, None otherwise.
+        Scans all registered plugin modes; for each plugin that has live
+        priority *and* live content, collects the specific live mode(s) it
+        reports via get_live_modes() (only those actually registered), falling
+        back to the scanned mode name when it ends in '_live'. Deduplicated,
+        preserving order. A plugin registered under several mode keys (the
+        sports plugins register one per league) contributes each live mode once.
         """
+        live = []
+        seen = set()
         for mode_name, plugin_instance in self.plugin_modes.items():
-            if hasattr(plugin_instance, 'has_live_priority') and hasattr(plugin_instance, 'has_live_content'):
+            if not (hasattr(plugin_instance, 'has_live_priority')
-                try:
+                    and hasattr(plugin_instance, 'has_live_content')):
-                    if plugin_instance.has_live_priority() and plugin_instance.has_live_content():
+                continue
-                        # Get the specific live mode from the plugin if available
+            try:
-                        if hasattr(plugin_instance, 'get_live_modes'):
+                if not (plugin_instance.has_live_priority()
-                            live_modes = plugin_instance.get_live_modes()
+                        and plugin_instance.has_live_content()):
-                            if live_modes and len(live_modes) > 0:
+                    continue
-                                # Verify the mode actually exists before returning it
+                resolved = []
-                                for suggested_mode in live_modes:
+                if hasattr(plugin_instance, 'get_live_modes'):
-                                    if suggested_mode in self.plugin_modes:
+                    for suggested_mode in (plugin_instance.get_live_modes() or []):
-                                        return suggested_mode
+                        if suggested_mode in self.plugin_modes:
-                                # If suggested modes don't exist, fall through to check current mode
+                            resolved.append(suggested_mode)
-                        # Fallback: if this mode ends with _live, return it
+                if not resolved and mode_name.endswith('_live'):
-                        if mode_name.endswith('_live'):
+                    resolved.append(mode_name)
-                            return mode_name
+                for m in resolved:
-                except Exception as e:
+                    if m not in seen:
-                    logger.warning("Error checking live priority for %s: %s", mode_name, e)
+                        seen.add(m)
-        return None
+                        live.append(m)
+            except Exception as e:
+                logger.warning("Error checking live priority for %s: %s", mode_name, e)
+        return live
+
+    def _check_live_priority(self, advance=False):
+        """Return the live-priority mode to display, or None if nothing is live.
+
+        When several plugins report live content at once (e.g. a baseball game
+        and a soccer match), this round-robins between them so the display
+        alternates each dwell instead of pinning to whichever plugin is first in
+        registration order.
+
+        advance=False (default): a non-advancing peek — returns the live mode
+        already on screen if it is still live, otherwise the first live mode.
+        Used by the Vegas coordinator and the vegas-active check, which only
+        need to know whether *any* game is live (and must not spin the cursor).
+
+        advance=True: the rotation pick — returns the live mode *after* the one
+        currently shown, so each dwell advances to the next live game. The
+        currently-displayed mode is the cursor, so this stays correct as games
+        start and end (no separate index to keep in sync).
+        """
+        live_modes = self._collect_live_modes()
+        if not live_modes:
+            return None
+        if self.current_display_mode in live_modes:
+            if advance:
+                idx = live_modes.index(self.current_display_mode)
+                return live_modes[(idx + 1) % len(live_modes)]
+            return self.current_display_mode
+        return live_modes[0]
 
     def run(self):
         """Run the display controller, switching between displays."""
@@ -1689,9 +1727,11 @@ class DisplayController:
                             # Display failed, clear the status and continue normally
                             wifi_status_data = None
 
-                # Check for live priority content and switch to it immediately
+                # Check for live priority content and switch to it immediately.
+                # advance=True so multiple simultaneously-live games take turns
+                # (round-robin) instead of pinning to the first plugin.
                 if not self.on_demand_active and not wifi_status_data:
-                    live_priority_mode = self._check_live_priority()
+                    live_priority_mode = self._check_live_priority(advance=True)
                     self._apply_live_priority(live_priority_mode)
 
                 # Vegas scroll mode - continuous ticker across all plugins
@@ -2186,6 +2226,23 @@ class DisplayController:
                                     loop_completed = True
                                     break
 
+                        # LOAD-BEARING: if current_display_mode changed mid-loop (on-demand
+                        # activation, live priority, etc.), restart the main loop now instead
+                        # of falling into the "honour minimum duration" sleep below. That sleep
+                        # can run for up to the *previous* mode's full display_duration (default
+                        # 30s) and doesn't poll on-demand requests or re-check the mode, so a
+                        # freshly-requested mode switch would sit invisible for up to 30s — or
+                        # get clobbered by a queued stop request — before ever rendering.
+                        #
+                        # This guard was added in #298 (live priority interrupting long display
+                        # durations) and was accidentally dropped in #330 as collateral damage of
+                        # an unrelated time.monotonic() -> time.time() cleanup in the same hunk.
+                        # Removing it again will silently reintroduce both issues. _activate_on_demand
+                        # already sets force_change=True and clears the display, so the next loop
+                        # iteration renders the new mode immediately.
+                        if self.current_display_mode != active_mode:
+                            continue
+
                         # Ensure we honour minimum duration when not dynamic and loop ended early
                         if (
                             not dynamic_enabled

src/plugin_system/state_reconciliation.py

@@ -322,10 +322,19 @@ class StateReconciliation:
                 and hasattr(self.store_manager, 'was_recently_uninstalled')
                 and self.store_manager.was_recently_uninstalled(plugin_id)
             )
+            # Also refuse to resurrect a plugin the user has persistently
+            # uninstalled. Unlike the in-memory race guard above, this record
+            # survives restarts, so the user's removal sticks across updates.
+            persistently_uninstalled = (
+                self.store_manager is not None
+                and hasattr(self.store_manager, 'is_plugin_uninstalled')
+                and self.store_manager.is_plugin_uninstalled(plugin_id)
+            )
             can_repair = (
                 self.store_manager is not None
                 and not previously_unrecoverable
                 and not recently_uninstalled
+                and not persistently_uninstalled
             )
             inconsistencies.append(Inconsistency(
                 plugin_id=plugin_id,

src/plugin_system/store_manager.py

@@ -7,6 +7,7 @@ from both the official registry and custom GitHub repositories.
 
 import hashlib
 import os
+import re
 import json
 import stat
 import subprocess
@@ -19,7 +20,7 @@ import time
 from concurrent.futures import ThreadPoolExecutor
 from datetime import datetime
 from pathlib import Path
-from typing import List, Dict, Optional, Any, Tuple
+from typing import List, Dict, Optional, Any, Tuple, Set
 import logging
 
 from urllib.parse import urlparse
@@ -44,12 +45,23 @@ class PluginStoreManager:
     
     REGISTRY_URL = "https://raw.githubusercontent.com/ChuckBuilds/ledmatrix-plugins/main/plugins.json"
 
-    def __init__(self, plugins_dir: str = "plugins"):
+    # A valid plugin id is a single path component: starts alphanumeric, then
+    # alphanumerics / dot / dash / underscore. Used to keep the uninstall
+    # registry from ever turning a corrupt or hand-edited entry (e.g. "",
+    # "..", "../x") into a filesystem path that purge_uninstalled_plugins
+    # would delete — an empty id resolves to the plugins root itself.
+    _PLUGIN_ID_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9._-]*$")
+    
+    def __init__(self, plugins_dir: str = "plugins",
+                 uninstalled_registry_path: Optional[str] = None):
         """
         Initialize the plugin store manager.
 
         Args:
             plugins_dir: Directory where plugins are installed
+            uninstalled_registry_path: Path to the JSON file recording plugins
+                the user has uninstalled. Defaults to
+                ``config/uninstalled_plugins.json`` under the project root.
         """
         self.plugins_dir = Path(plugins_dir)
         self.logger = logging.getLogger(__name__)
@@ -84,6 +96,25 @@ class PluginStoreManager:
         self._uninstall_tombstones: Dict[str, float] = {}
         self._uninstall_tombstone_ttl = 300  # 5 minutes
 
+        # Persistent record of plugins the user has uninstalled. Unlike the
+        # in-memory tombstones above (a short-lived race guard), this survives
+        # restarts so that a core ``git pull`` update cannot resurrect a
+        # built-in plugin the user removed. Built-in plugins (e.g.
+        # ``web-ui-info``, ``starlark-apps``) are committed into the repo under
+        # ``plugin-repos/``, so a plain ``git pull`` restores their files even
+        # after the user deleted them. ``purge_uninstalled_plugins`` re-removes
+        # any such resurrected directory; ``install_plugin`` clears the record
+        # when the user deliberately reinstalls. The file is gitignored.
+        if uninstalled_registry_path is not None:
+            self._uninstalled_registry_path = Path(uninstalled_registry_path)
+        else:
+            self._uninstalled_registry_path = (
+                Path(__file__).parent.parent.parent / "config" / "uninstalled_plugins.json"
+            )
+        # Serializes read-modify-write of the registry file so concurrent
+        # install/uninstall requests can't lose updates.
+        self._uninstalled_registry_lock = threading.Lock()
+
         # Cache for _get_local_git_info: {plugin_path_str: (signature, data)}
         # where ``signature`` is a tuple of (head_mtime, resolved_ref_mtime,
         # head_contents) so a fast-forward update to the current branch
@@ -143,6 +174,135 @@ class PluginStoreManager:
             return False
         return True
 
+    def _is_valid_plugin_id(self, plugin_id: Any) -> bool:
+        """Return True if ``plugin_id`` is a safe single-component plugin id.
+
+        Rejects empty strings, anything with a path separator, and traversal
+        sequences like ``..`` so a registry entry can never escape (or target
+        the root of) ``self.plugins_dir`` during a purge.
+        """
+        return isinstance(plugin_id, str) and bool(self._PLUGIN_ID_RE.match(plugin_id))
+
+    def _read_uninstalled_registry(self) -> Set[str]:
+        """Read the persistent set of uninstalled plugin IDs.
+
+        Returns an empty set if the file is missing, unreadable, or corrupt —
+        a broken registry must never block normal plugin operations. Invalid
+        ids are dropped here so callers never turn them into paths.
+        """
+        try:
+            if not self._uninstalled_registry_path.exists():
+                return set()
+            with open(self._uninstalled_registry_path, 'r', encoding='utf-8') as f:
+                data = json.load(f)
+            if not isinstance(data, list):
+                self.logger.warning(
+                    "Uninstalled-plugin registry at %s is not a list; ignoring it",
+                    self._uninstalled_registry_path,
+                )
+                return set()
+            valid: Set[str] = set()
+            for pid in data:
+                if self._is_valid_plugin_id(pid):
+                    valid.add(pid)
+                else:
+                    self.logger.warning(
+                        "Ignoring invalid plugin id in uninstall registry: %r", pid
+                    )
+            return valid
+        except (OSError, ValueError) as e:
+            self.logger.warning(
+                "Could not read uninstalled-plugin registry at %s: %s",
+                self._uninstalled_registry_path, e,
+            )
+            return set()
+
+    def _write_uninstalled_registry(self, plugin_ids: Set[str]) -> None:
+        """Persist the set of uninstalled plugin IDs (sorted, atomically)."""
+        path = self._uninstalled_registry_path
+        try:
+            path.parent.mkdir(parents=True, exist_ok=True)
+            tmp_path = path.with_suffix(path.suffix + ".tmp")
+            with open(tmp_path, 'w', encoding='utf-8') as f:
+                json.dump(sorted(plugin_ids), f, indent=2)
+            os.replace(tmp_path, path)
+        except OSError as e:
+            self.logger.error(
+                "Failed to write uninstalled-plugin registry at %s: %s", path, e
+            )
+
+    def record_uninstalled_plugin(self, plugin_id: str) -> None:
+        """Persistently record that the user uninstalled ``plugin_id``.
+
+        Survives restarts so a core update cannot resurrect the plugin.
+        """
+        if not self._is_valid_plugin_id(plugin_id):
+            self.logger.error("Refusing to record invalid plugin id: %r", plugin_id)
+            return
+        with self._uninstalled_registry_lock:
+            recorded = self._read_uninstalled_registry()
+            if plugin_id not in recorded:
+                recorded.add(plugin_id)
+                self._write_uninstalled_registry(recorded)
+                self.logger.info("Recorded %s as uninstalled (persistent)", plugin_id)
+
+    def forget_uninstalled_plugin(self, *plugin_ids: str) -> None:
+        """Drop ``plugin_ids`` from the persistent uninstall registry.
+
+        Called when a plugin is deliberately (re)installed so future updates
+        keep it.
+        """
+        with self._uninstalled_registry_lock:
+            recorded = self._read_uninstalled_registry()
+            to_remove = {pid for pid in plugin_ids if pid in recorded}
+            if to_remove:
+                self._write_uninstalled_registry(recorded - to_remove)
+                self.logger.info(
+                    "Cleared uninstall record for %s", ", ".join(sorted(to_remove))
+                )
+
+    def get_uninstalled_plugins(self) -> Set[str]:
+        """Return the persistent set of user-uninstalled plugin IDs."""
+        return self._read_uninstalled_registry()
+
+    def is_plugin_uninstalled(self, plugin_id: str) -> bool:
+        """Return True if ``plugin_id`` is in the persistent uninstall registry."""
+        return plugin_id in self._read_uninstalled_registry()
+
+    def purge_uninstalled_plugins(self) -> List[str]:
+        """Remove on-disk directories for plugins the user has uninstalled.
+
+        Built-in plugins committed into the repo are restored on disk by a
+        core ``git pull``; this re-removes any that the user previously
+        uninstalled. The registry entries are kept so the purge is idempotent
+        across every future update (until the user reinstalls). Returns the
+        list of plugin IDs whose directories were actually removed.
+        """
+        removed: List[str] = []
+        plugins_root = self.plugins_dir.resolve()
+        for plugin_id in sorted(self._read_uninstalled_registry()):
+            plugin_path = self.plugins_dir / plugin_id
+            # Defense in depth: ids are already validated on read, but never
+            # remove anything that isn't a direct child of the plugins root.
+            resolved = plugin_path.resolve()
+            if resolved == plugins_root or resolved.parent != plugins_root:
+                self.logger.error(
+                    "Refusing to purge unsafe plugin path for id %r", plugin_id
+                )
+                continue
+            if not plugin_path.exists():
+                continue
+            self.logger.info(
+                "Purging resurrected uninstalled plugin: %s", plugin_id
+            )
+            if self._safe_remove_directory(plugin_path):
+                removed.append(plugin_id)
+            else:
+                self.logger.error(
+                    "Failed to purge resurrected plugin directory: %s", plugin_path
+                )
+        return removed
+
     def _load_github_token(self) -> Optional[str]:
         """
         Load GitHub API token from config_secrets.json if available.
@@ -1024,6 +1184,10 @@ class PluginStoreManager:
         branch_info = f" (branch: {branch})" if branch else " (latest branch head)"
         self.logger.info(f"Installing plugin: {plugin_id}{branch_info}")
 
+        # Remember the originally-requested id so we can clear its uninstall
+        # record on success even if the manifest renames the directory below.
+        requested_id = plugin_id
+
         plugin_info = self.get_plugin_info(plugin_id, fetch_latest_from_github=True, force_refresh=True)
         if not plugin_info:
             self.logger.error(f"Plugin not found in registry: {plugin_id}")
@@ -1162,6 +1326,9 @@ class PluginStoreManager:
 
             branch_display = branch_used or plugin_info.get('branch') or plugin_info.get('default_branch', 'unknown')
             self.logger.info(f"Successfully installed plugin: {plugin_id} (branch {branch_display})")
+            # User deliberately (re)installed this plugin — clear any persistent
+            # uninstall record so future core updates keep it.
+            self.forget_uninstalled_plugin(requested_id, plugin_id)
             return True
 
         except Exception as e:

src/plugin_system/testing/__init__.py

@@ -7,13 +7,22 @@ Provides base classes and utilities for testing LEDMatrix plugins.
 from .plugin_test_base import PluginTestCase
 from .mocks import MockDisplayManager, MockCacheManager, MockConfigManager, MockPluginManager
 from .visual_display_manager import VisualTestDisplayManager
+from .bounds_display_manager import BoundsCheckingDisplayManager
+from .sizes import (
+    DEFAULT_TEST_SIZES, SUPPORTED_SIZES, resolve_test_sizes, size_label,
+)
 
 __all__ = [
     'PluginTestCase',
     'VisualTestDisplayManager',
+    'BoundsCheckingDisplayManager',
     'MockDisplayManager',
     'MockCacheManager',
     'MockConfigManager',
     'MockPluginManager',
+    'DEFAULT_TEST_SIZES',
+    'SUPPORTED_SIZES',
+    'resolve_test_sizes',
+    'size_label',
 ]
 

src/plugin_system/testing/bounds_display_manager.py

@@ -0,0 +1,129 @@
+"""
+Bounds-checking display manager.
+
+A VisualTestDisplayManager that draws onto an oversized canvas (the declared
+panel size plus a right/bottom margin) while still reporting the declared size
+to the plugin. Content that a plugin draws past the right or bottom edge lands
+in the margin instead of being silently clipped by PIL, so the harness can
+detect overflow — the classic symptom of hardcoded coordinates or fonts/icons
+that don't scale down to a smaller panel.
+
+Limitations (documented on purpose):
+- Overflow past the LEFT or TOP edge (negative coordinates) is still clipped by
+  PIL and not detected here. The dominant real-world breakage is content that is
+  too wide/tall for a smaller panel, which this catches.
+- BDF text is clipped to the declared bounds by the parent's bitmap drawer, so
+  BDF overflow is not flagged. Golden-image regression covers those plugins.
+- If a plugin replaces the canvas with its own image (display_manager.image = ...),
+  the margin can't be measured and overflow is reported as undetermined (None).
+"""
+
+from typing import Optional, Tuple
+
+from .sizes import DEFAULT_TEST_SIZES
+from .visual_display_manager import VisualTestDisplayManager, _MatrixProxy
+
+# Smallest extra band kept on the right/bottom so a few pixels of overflow are
+# still visible even on the largest panel in a run.
+_BASE_MARGIN = 16
+# Fallback overflow reference when a caller doesn't pass one: the largest shape
+# in the default sample. We extend every (smaller) canvas out to at least this
+# size so content drawn at a coordinate meant for a bigger build — e.g. x=200 on
+# a 64-wide panel — lands in the padded region and is flagged, instead of being
+# clipped off-canvas and read as a false pass.
+_DEFAULT_EXTENT_WIDTH = max(w for w, _ in DEFAULT_TEST_SIZES)
+_DEFAULT_EXTENT_HEIGHT = max(h for _, h in DEFAULT_TEST_SIZES)
+
+
+class BoundsCheckingDisplayManager(VisualTestDisplayManager):
+    """Detects drawing that overflows the declared panel size."""
+
+    # Kept for backwards compatibility; real padding is computed per-axis below.
+    MARGIN = _BASE_MARGIN
+
+    def __init__(self, width: int = 128, height: int = 32,
+                 overflow_extent: Optional[Tuple[int, int]] = None):
+        self._declared_width = int(width)
+        self._declared_height = int(height)
+        # Pad the canvas out to at least `overflow_extent` (the largest panel
+        # this run cares about) plus a base margin, so coordinates meant for a
+        # bigger build are caught — not clipped — when rendering a smaller panel.
+        # Defaults to the largest shape in the sample when no run is known.
+        ext_w, ext_h = overflow_extent or (_DEFAULT_EXTENT_WIDTH, _DEFAULT_EXTENT_HEIGHT)
+        self._canvas_width = max(self._declared_width, int(ext_w)) + _BASE_MARGIN
+        self._canvas_height = max(self._declared_height, int(ext_h)) + _BASE_MARGIN
+        # Parent builds the (oversized) backing canvas + fonts.
+        super().__init__(self._canvas_width, self._canvas_height)
+        # Plugins must see the DECLARED size, not the padded canvas size.
+        self.matrix = _MatrixProxy(self._declared_width, self._declared_height)
+
+    # -- declared dimensions (override parent's image-derived properties) --
+
+    @property
+    def width(self) -> int:
+        return self._declared_width
+
+    @property
+    def height(self) -> int:
+        return self._declared_height
+
+    @property
+    def display_width(self) -> int:
+        return self._declared_width
+
+    @property
+    def display_height(self) -> int:
+        return self._declared_height
+
+    # -- overflow detection --
+
+    def _canvas_is_padded(self) -> bool:
+        return self.image.size == (self._canvas_width, self._canvas_height)
+
+    def check_overflow(self) -> Optional[Tuple[int, int, int, int]]:
+        """Bounding box (in full-canvas coords) of any drawing beyond the
+        declared panel, or None if nothing overflowed / undetermined."""
+        if not self._canvas_is_padded():
+            return None
+
+        exp_w = self._canvas_width
+        exp_h = self._canvas_height
+        boxes = []
+
+        right = self.image.crop((self._declared_width, 0, exp_w, exp_h)).getbbox()
+        if right:
+            boxes.append((right[0] + self._declared_width, right[1],
+                          right[2] + self._declared_width, right[3]))
+
+        bottom = self.image.crop((0, self._declared_height, exp_w, exp_h)).getbbox()
+        if bottom:
+            boxes.append((bottom[0], bottom[1] + self._declared_height,
+                          bottom[2], bottom[3] + self._declared_height))
+
+        if not boxes:
+            return None
+        return (
+            min(b[0] for b in boxes), min(b[1] for b in boxes),
+            max(b[2] for b in boxes), max(b[3] for b in boxes),
+        )
+
+    # -- snapshot/image accessors return the cropped, true-panel image --
+
+    def declared_image(self):
+        """The visible panel: the canvas cropped to the declared size."""
+        if self._canvas_is_padded():
+            return self.image.crop((0, 0, self._declared_width, self._declared_height))
+        return self.image
+
+    def save_snapshot(self, path: str) -> None:
+        self.declared_image().save(path, format='PNG')
+
+    def get_image(self):
+        return self.declared_image()
+
+    def get_image_base64(self) -> str:
+        import base64
+        import io
+        buffer = io.BytesIO()
+        self.declared_image().save(buffer, format='PNG')
+        return base64.b64encode(buffer.getvalue()).decode('utf-8')

src/plugin_system/testing/harness.py

@@ -0,0 +1,314 @@
+"""
+Plugin safety harness.
+
+Renders a plugin across every declared screen (mode) and every supported matrix
+size, capturing crashes and overflow. Used by scripts/check_plugin.py and the
+pytest matrix test to guarantee a plugin change doesn't break a screen at a size
+the author didn't try.
+
+The render flow mirrors scripts/render_plugin.py (same PluginLoader call), but
+this module adds: multi-size iteration, per-mode rendering, overflow detection
+via BoundsCheckingDisplayManager, and golden-image comparison.
+"""
+
+import contextlib
+import http.client
+import inspect
+import socket
+import ssl
+import urllib.error
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any, Dict, List, Optional, Tuple
+
+from PIL import Image, ImageChops
+
+from src.logging_config import get_logger
+from .bounds_display_manager import BoundsCheckingDisplayManager
+from .loading import load_config_defaults, load_manifest
+from .sizes import DEFAULT_TEST_SIZES, safe_mode_filename, size_label
+
+logger = get_logger("[Plugin Harness]")
+
+
+def _tolerated_update_errors() -> Tuple[type, ...]:
+    """Exception types from update() we treat as a tolerated no-connectivity
+    failure (expected in CI / headless dev) rather than a real plugin bug.
+
+    Anything NOT in this set is a genuine regression — a plugin that lets a
+    non-network exception escape update() should fail the harness, not pass
+    green because display() happened to survive.
+    """
+    types: List[type] = [
+        ConnectionError, TimeoutError,        # builtins
+        socket.gaierror, socket.timeout,      # DNS / socket timeouts
+        ssl.SSLError,
+        urllib.error.URLError,
+        http.client.HTTPException,
+    ]
+    try:  # requests is optional; cover its whole error tree when present
+        import requests
+        types.append(requests.exceptions.RequestException)
+    except ImportError:  # pragma: no cover - requests not installed
+        logger.debug("requests not installed; its connectivity errors won't be specifically tolerated")
+    return tuple(types)
+
+
+_TOLERATED_UPDATE_ERRORS = _tolerated_update_errors()
+
+
+@dataclass
+class RenderResult:
+    """Outcome of rendering one (size, mode) of a plugin."""
+    plugin_id: str
+    width: int
+    height: int
+    mode: str
+    image: Optional[Image.Image] = None
+    error: Optional[str] = None          # fatal: load/display crash, or a non-network update() error
+    update_error: Optional[str] = None   # tolerated: connectivity error from update() (no network in CI)
+    overflow: Optional[Tuple[int, int, int, int]] = None  # bbox past the panel
+    # golden comparison (populated only when a golden was provided)
+    golden_checked: bool = False
+    golden_ok: Optional[bool] = None
+    golden_diff_pixels: int = 0
+    golden_max_delta: int = 0
+
+    @property
+    def size_label(self) -> str:
+        return size_label(self.width, self.height)
+
+    @property
+    def ok(self) -> bool:
+        """Phase-1 pass: rendered without crashing and without overflow, and if a
+        golden was checked it matched."""
+        if self.error is not None or self.overflow is not None:
+            return False
+        if self.golden_checked and self.golden_ok is False:
+            return False
+        return True
+
+
+def list_modes(plugin_instance: Any, manifest: Dict[str, Any], plugin_id: str) -> List[str]:
+    """Enumerate a plugin's screens: instance.modes wins, then manifest
+    display_modes, then the plugin id as a single mode."""
+    modes = getattr(plugin_instance, "modes", None)
+    if modes:
+        return [str(m) for m in modes]
+    declared = manifest.get("display_modes")
+    if declared:
+        return [str(m) for m in declared]
+    return [plugin_id]
+
+
+def _instantiate(plugin_id: str, manifest: Dict[str, Any], plugin_dir: Path,
+                 config: Dict[str, Any], mock_data: Dict[str, Any],
+                 display_manager: Any) -> Any:
+    """Load and construct a plugin instance with mocked managers."""
+    from src.plugin_system.plugin_loader import PluginLoader
+    from src.plugin_system.testing import MockCacheManager, MockPluginManager
+
+    cache_manager = MockCacheManager()
+    for key, value in (mock_data or {}).items():
+        cache_manager.set(key, value)
+
+    loader = PluginLoader()
+    plugin_instance, _module = loader.load_plugin(
+        plugin_id=plugin_id,
+        manifest=manifest,
+        plugin_dir=plugin_dir,
+        config=config,
+        display_manager=display_manager,
+        cache_manager=cache_manager,
+        plugin_manager=MockPluginManager(),
+        install_deps=False,
+    )
+    return plugin_instance
+
+
+def _render_mode(plugin_instance: Any, mode: str) -> None:
+    """Render a specific screen. Prefer an explicit display_mode kwarg; otherwise
+    drive the plugin's internal mode state machine (first display() call renders
+    modes[current_mode_index] when current_display_mode is None)."""
+    sig = inspect.signature(plugin_instance.display)
+    if "display_mode" in sig.parameters:
+        plugin_instance.display(force_clear=True, display_mode=mode)
+        return
+
+    modes = getattr(plugin_instance, "modes", None)
+    if modes and mode in modes:
+        plugin_instance.current_mode_index = list(modes).index(mode)
+    if hasattr(plugin_instance, "current_display_mode"):
+        plugin_instance.current_display_mode = None
+    plugin_instance.display(force_clear=False)
+
+
+def _freeze(freeze_time: Optional[str]):
+    """Context manager that freezes wall-clock time when freeze_time is given,
+    so time-dependent plugins (clocks, countdowns) render deterministic goldens."""
+    if not freeze_time:
+        return contextlib.nullcontext()
+    try:
+        from freezegun import freeze_time as _ft
+    except ImportError as e:  # pragma: no cover - only hit without the dep
+        raise RuntimeError(
+            "freeze_time requires the 'freezegun' package (pip install freezegun)"
+        ) from e
+    return _ft(freeze_time)
+
+
+def render_plugin_matrix(
+    plugin_id: str,
+    plugin_dir: Path,
+    config: Optional[Dict[str, Any]] = None,
+    mock_data: Optional[Dict[str, Any]] = None,
+    sizes: Optional[List[Tuple[int, int]]] = None,
+    run_update: bool = True,
+    freeze_time: Optional[str] = None,
+) -> List[RenderResult]:
+    """Render every (size, mode) combination for a plugin.
+
+    Returns a flat list of RenderResult. A fresh plugin instance is built per
+    (size, mode) so state never leaks between screens. Pass freeze_time (e.g.
+    "2025-08-01 15:25:00") to make time-dependent plugins reproducible.
+    """
+    plugin_dir = Path(plugin_dir)
+    manifest = load_manifest(plugin_dir)
+    # Start from config_schema.json defaults so the plugin behaves like a real
+    # install; explicit caller config still wins over a schema default.
+    config = {"enabled": True, **load_config_defaults(plugin_dir), **(config or {})}
+    sizes = sizes or DEFAULT_TEST_SIZES
+    results: List[RenderResult] = []
+
+    # The largest panel in this run. Every (smaller) canvas is padded out to it
+    # so a coordinate meant for the biggest configuration is still caught when
+    # rendering a smaller one, instead of being clipped into a false pass.
+    extent = (max(w for w, _ in sizes), max(h for _, h in sizes))
+
+    with _freeze(freeze_time):
+        for width, height in sizes:
+            results.extend(_render_size(
+                plugin_id, manifest, plugin_dir, config, mock_data or {},
+                width, height, run_update, extent,
+            ))
+
+    return results
+
+
+def _render_size(plugin_id, manifest, plugin_dir, config, mock_data,
+                 width, height, run_update, extent) -> List[RenderResult]:
+    """Render every mode at one size. A fresh instance per mode avoids state leaks."""
+    results: List[RenderResult] = []
+
+    # Discover modes once per size (instance build can depend on config).
+    try:
+        probe_dm = BoundsCheckingDisplayManager(width=width, height=height, overflow_extent=extent)
+        probe = _instantiate(plugin_id, manifest, plugin_dir, config, mock_data, probe_dm)
+        modes = list_modes(probe, manifest, plugin_id)
+    except Exception as e:  # noqa: BLE001 — surface any load failure as a result
+        return [RenderResult(plugin_id, width, height, "<load>", error=repr(e))]
+
+    for mode in modes:
+        result = RenderResult(plugin_id, width, height, mode)
+        dm = BoundsCheckingDisplayManager(width=width, height=height, overflow_extent=extent)
+        try:
+            inst = _instantiate(plugin_id, manifest, plugin_dir, config, mock_data, dm)
+            if run_update:
+                try:
+                    inst.update()
+                except _TOLERATED_UPDATE_ERRORS as e:
+                    # Expected when CI / headless dev has no network: record it
+                    # (surfaced in the report) but don't fail the run.
+                    result.update_error = repr(e)
+                    logger.debug("update() connectivity error for %s [%s]: %s", plugin_id, mode, e)
+                except Exception as e:  # noqa: BLE001 — a non-network update() failure is a real bug
+                    # A regression in update() must not pass green just because
+                    # display() survives, so treat it as a failure of this render.
+                    result.error = repr(e)
+                    logger.warning("update() raised a non-connectivity error for %s [%s]: %s",
+                                   plugin_id, mode, e)
+            if result.error is None:
+                _render_mode(inst, mode)
+                result.image = dm.get_image()
+                result.overflow = dm.check_overflow()
+        except Exception as e:  # noqa: BLE001 — a display crash is a real failure
+            result.error = repr(e)
+        results.append(result)
+
+    return results
+
+
+# ---------------------------------------------------------------------------
+# Golden-image comparison
+# ---------------------------------------------------------------------------
+
+def compare_images(rendered: Image.Image, golden: Image.Image,
+                   max_delta: int = 0, max_diff_pixels: int = 0) -> Tuple[bool, int, int]:
+    """Compare two images. Returns (ok, diff_pixel_count, max_per_channel_delta).
+
+    Tolerances default to exact match; bump them only to absorb known platform
+    anti-aliasing noise (requires a pinned Pillow + bundled fonts for stability).
+    """
+    if rendered.size != golden.size:
+        return False, rendered.size[0] * rendered.size[1], 255
+    a = rendered.convert("RGB")
+    b = golden.convert("RGB")
+    diff = ImageChops.difference(a, b)
+    bbox = diff.getbbox()
+    if bbox is None:
+        return True, 0, 0
+    # Count pixels whose largest per-channel delta exceeds the allowed tolerance,
+    # and track the worst delta seen (for reporting).
+    diff_pixels = 0
+    observed_max = 0
+    for px in diff.crop(bbox).getdata():
+        m = max(px) if isinstance(px, tuple) else px
+        if m > observed_max:
+            observed_max = m
+        if m > max_delta:
+            diff_pixels += 1
+    # Pass when the number of out-of-tolerance pixels is within budget.
+    ok = diff_pixels <= max_diff_pixels
+    return ok, diff_pixels, observed_max
+
+
+def golden_path(golden_dir: Path, width: int, height: int, mode: str) -> Path:
+    """Location of a golden image: <golden_dir>/<WxH>/<mode>.png.
+
+    The mode is sanitized to a safe basename so a mode name with '/' or '..'
+    can't read or write outside the golden directory.
+    """
+    return Path(golden_dir) / size_label(width, height) / f"{safe_mode_filename(mode)}.png"
+
+
+def compare_to_goldens(results: List[RenderResult], golden_dir: Path,
+                       max_delta: int = 0, max_diff_pixels: int = 0) -> List[RenderResult]:
+    """Compare rendered results against committed goldens, mutating each result's
+    golden_* fields. Results with no golden file on disk are left unchecked."""
+    for r in results:
+        if r.image is None:
+            continue
+        gp = golden_path(golden_dir, r.width, r.height, r.mode)
+        if not gp.exists():
+            continue
+        r.golden_checked = True
+        with Image.open(gp) as g:
+            ok, diff_pixels, observed_max = compare_images(
+                r.image, g, max_delta=max_delta, max_diff_pixels=max_diff_pixels)
+        r.golden_ok = ok
+        r.golden_diff_pixels = diff_pixels
+        r.golden_max_delta = observed_max
+    return results
+
+
+def write_goldens(results: List[RenderResult], golden_dir: Path) -> int:
+    """Write each successfully-rendered result to its golden path. Returns count."""
+    written = 0
+    for r in results:
+        if r.image is None or r.error is not None:
+            continue
+        gp = golden_path(golden_dir, r.width, r.height, r.mode)
+        gp.parent.mkdir(parents=True, exist_ok=True)
+        r.image.save(gp, format="PNG")
+        written += 1
+    return written

src/plugin_system/testing/loading.py

@@ -0,0 +1,82 @@
+"""
+Shared helpers for loading a plugin headlessly.
+
+Used by scripts/render_plugin.py, scripts/check_plugin.py, and the harness so
+plugin discovery / manifest / config-default logic lives in exactly one place.
+"""
+
+import json
+from pathlib import Path
+from typing import Any, Dict, Optional, Sequence, Union
+
+
+def find_plugin_dir(plugin_id: str, search_dirs: Sequence[Union[str, Path]]) -> Optional[Path]:
+    """Find a plugin directory by searching multiple paths."""
+    from src.plugin_system.plugin_loader import PluginLoader
+    loader = PluginLoader()
+    for search_dir in search_dirs:
+        search_path = Path(search_dir)
+        if not search_path.exists():
+            continue
+        result = loader.find_plugin_directory(plugin_id, search_path)
+        if result:
+            return Path(result)
+    return None
+
+
+def load_manifest(plugin_dir: Union[str, Path]) -> Dict[str, Any]:
+    """Load and return manifest.json from a plugin directory."""
+    manifest_path = Path(plugin_dir) / 'manifest.json'
+    if not manifest_path.exists():
+        raise FileNotFoundError(f"No manifest.json in {plugin_dir}")
+    with open(manifest_path, 'r') as f:
+        return json.load(f)
+
+
+def load_config_defaults(plugin_dir: Union[str, Path]) -> Dict[str, Any]:
+    """Extract default values from a plugin's config_schema.json (empty if none)."""
+    schema_path = Path(plugin_dir) / 'config_schema.json'
+    if not schema_path.exists():
+        return {}
+    with open(schema_path, 'r') as f:
+        schema = json.load(f)
+    defaults: Dict[str, Any] = {}
+    for key, prop in schema.get('properties', {}).items():
+        if isinstance(prop, dict) and 'default' in prop:
+            defaults[key] = prop['default']
+    return defaults
+
+
+def load_harness_spec(plugin_dir: Union[str, Path]) -> Dict[str, Any]:
+    """Optional per-plugin harness settings from <plugin>/test/harness.json.
+
+    Lets a plugin opt into golden-image testing by declaring how to render it
+    deterministically. All keys optional:
+        {
+          "config":     {...},            # config overrides
+          "mock_data":  "fixtures/mock.json",  # path (relative to plugin dir) to cache fixtures
+          "freeze_time": "2025-08-01 15:25:00",
+          "skip_update": false
+        }
+    Returns {} when no harness.json exists.
+    """
+    spec_path = Path(plugin_dir) / 'test' / 'harness.json'
+    if not spec_path.exists():
+        return {}
+    with open(spec_path, 'r') as f:
+        spec = json.load(f)
+
+    # Resolve mock_data path and inline its contents for convenience.
+    mock_rel = spec.get('mock_data')
+    if mock_rel:
+        mock_path = Path(plugin_dir) / mock_rel
+        if not mock_path.exists():
+            # A declared-but-missing fixture is a harness config error: failing
+            # loudly beats silently rendering the plugin with no mock data.
+            raise FileNotFoundError(
+                f"harness.json references mock_data '{mock_rel}' but "
+                f"{mock_path} does not exist"
+            )
+        with open(mock_path, 'r') as mf:
+            spec['mock_data_contents'] = json.load(mf)
+    return spec

src/plugin_system/testing/mocks.py

@@ -63,11 +63,23 @@ class MockCacheManager:
     """Mock cache manager for testing."""
     
     def __init__(self):
+        import shutil
+        import tempfile
+        import weakref
         self._cache: Dict[str, Any] = {}
         self._cache_timestamps: Dict[str, float] = {}
         self.get_calls = []
         self.set_calls = []
         self.delete_calls = []
+        # Real temp dir for plugins that write/read files under cache_dir.
+        # Registered for cleanup so each mock instance doesn't leak a tmp dir.
+        self.cache_dir = tempfile.mkdtemp(prefix="ledmatrix-mock-cache-")
+        self._finalizer = weakref.finalize(
+            self, shutil.rmtree, self.cache_dir, ignore_errors=True)
+
+    def cleanup(self) -> None:
+        """Remove the temp cache directory created for this instance."""
+        self._finalizer()
     
     def get(self, key: str, max_age: Optional[float] = None) -> Optional[Any]:
         """Get a value from cache."""

src/plugin_system/testing/sizes.py

@@ -0,0 +1,120 @@
+"""
+LED matrix sizes the plugin safety harness renders against.
+
+There is no fixed set of "supported" panel sizes — an RGB matrix build can be
+any width/height and configuration (square, rectangle, 2x2, 4x4, 8x2, long
+strips, tall stacks, ...). Plugins are expected to read width/height
+dynamically and lay themselves out accordingly, so the harness's job is to
+prove a plugin survives a *spread* of shapes, not a canonical list.
+
+`DEFAULT_TEST_SIZES` is therefore a representative SAMPLE chosen to span the
+axes of variation (narrow, wide, square, tall, small, long), not an
+exhaustive or authoritative list. Callers can override it entirely:
+
+  - CLI:        scripts/check_plugin.py --sizes 8x16,64x64,256x32
+  - pytest:     LEDMATRIX_TEST_SIZES="8x16,64x64" env var (all plugins), or
+                per-plugin test/harness.json {"sizes": [[8, 16], [64, 64]]}
+
+so anyone can point the harness at the exact panel(s) their build uses.
+"""
+
+import os
+from typing import Iterable, List, Optional, Sequence, Tuple, Union
+
+# A spread of real panel-grid arrangements (each module is 64x32), not a list of
+# "blessed" sizes. Each entry exercises a different layout assumption a plugin
+# might accidentally bake in. Annotations are the panel grid (cols x rows).
+DEFAULT_TEST_SIZES: List[Tuple[int, int]] = [
+    (64, 32),    # 1x1 — single panel, the tightest common rectangle
+    (128, 32),   # 2x1 — the baseline most plugins are tuned for
+    (64, 64),    # 1x2 — stacked, exercises tall-narrow centering
+    (128, 64),   # 2x2 — block, icon scaling / vertical centering
+    (256, 32),   # 4x1 — long strip, wide horizontal layout
+    (128, 96),   # 2x3 — tall, exercises vertical overflow
+    (256, 128),  # 4x4 — large block, both dimensions big at once
+]
+
+# Backwards-compatible alias. Prefer DEFAULT_TEST_SIZES in new code — the old
+# name implied these were the only valid panel sizes, which they are not.
+SUPPORTED_SIZES = DEFAULT_TEST_SIZES
+
+
+def size_label(width: int, height: int) -> str:
+    """Human/path-friendly label for a size, e.g. '128x32'."""
+    return f"{width}x{height}"
+
+
+def parse_size_token(token: str) -> Tuple[int, int]:
+    """Parse a single 'WxH' token into an (int, int) pair.
+
+    Raises ValueError (with a user-friendly message) on malformed input so
+    callers can surface it however they like.
+    """
+    cleaned = token.strip().lower()
+    if "x" not in cleaned:
+        raise ValueError(f"Invalid size '{token}' (expected WxH, e.g. 128x32)")
+    w, h = cleaned.split("x", 1)
+    try:
+        width, height = int(w), int(h)
+    except ValueError as exc:
+        raise ValueError(
+            f"Invalid size '{token}' (expected numeric WxH, e.g. 128x32)"
+        ) from exc
+    if width <= 0 or height <= 0:
+        raise ValueError(
+            f"Invalid size '{token}' (width and height must be positive, e.g. 128x32)"
+        )
+    return (width, height)
+
+
+def coerce_sizes(
+    value: Union[str, Iterable[Sequence[int]], None]
+) -> Optional[List[Tuple[int, int]]]:
+    """Normalize a size spec into a list of (w, h) tuples, or None if empty.
+
+    Accepts a comma-separated 'WxH,WxH' string (CLI / env var) or an iterable
+    of [w, h] / (w, h) pairs (harness.json). Returns None when value is falsy
+    so callers can fall back to the default sample.
+    """
+    if not value:
+        return None
+    if isinstance(value, str):
+        return [parse_size_token(tok) for tok in value.split(",") if tok.strip()]
+    sizes: List[Tuple[int, int]] = []
+    for pair in value:
+        w, h = pair  # raises if not a 2-element sequence
+        width, height = int(w), int(h)
+        if width <= 0 or height <= 0:
+            raise ValueError(f"Invalid size pair {pair!r} (width and height must be positive)")
+        sizes.append((width, height))
+    return sizes or None
+
+
+def resolve_test_sizes(
+    spec_sizes: Union[str, Iterable[Sequence[int]], None] = None,
+) -> List[Tuple[int, int]]:
+    """Decide which sizes to render, by precedence:
+
+    1. LEDMATRIX_TEST_SIZES env var — a global "test on my hardware" override
+       that wins for every plugin.
+    2. spec_sizes — e.g. a per-plugin harness.json "sizes" list.
+    3. DEFAULT_TEST_SIZES — the representative sample.
+    """
+    env = coerce_sizes(os.environ.get("LEDMATRIX_TEST_SIZES"))
+    if env:
+        return env
+    spec = coerce_sizes(spec_sizes)
+    if spec:
+        return spec
+    return list(DEFAULT_TEST_SIZES)
+
+
+def safe_mode_filename(mode: str) -> str:
+    """A filesystem-safe basename for a plugin mode.
+
+    Mode names come from plugin metadata/render state, so a value containing
+    '/' or '..' could otherwise escape the intended output directory. Collapse
+    anything that isn't alphanumeric / dash / underscore to '_'.
+    """
+    cleaned = "".join(ch if ch.isalnum() or ch in ("-", "_") else "_" for ch in mode)
+    return cleaned or "mode"

test/plugins/test_harness.py

@@ -0,0 +1,255 @@
+"""
+Unit tests for the plugin safety harness primitives:
+bounds detection, image comparison, and mode enumeration.
+
+These don't load real plugins, so they run anywhere (including core CI where
+plugin-repos is empty).
+"""
+
+import importlib.util
+import json
+from pathlib import Path
+
+import pytest
+from PIL import Image
+
+from src.plugin_system.testing.bounds_display_manager import BoundsCheckingDisplayManager
+from src.plugin_system.testing.harness import (
+    _TOLERATED_UPDATE_ERRORS, compare_images, list_modes,
+)
+from src.plugin_system.testing.sizes import (
+    DEFAULT_TEST_SIZES, coerce_sizes, parse_size_token, resolve_test_sizes,
+)
+
+
+class TestBoundsDetection:
+    def test_reports_declared_size_not_canvas_size(self):
+        dm = BoundsCheckingDisplayManager(width=64, height=32)
+        assert dm.width == 64 and dm.height == 32
+        assert dm.matrix.width == 64 and dm.matrix.height == 32
+        # Backing canvas is padded out past the declared panel so far-overshoot
+        # coordinates land on-canvas and get flagged instead of clipped.
+        canvas_w, canvas_h = dm.image.size
+        assert canvas_w > 64 and canvas_h > 32
+
+    def test_far_overshoot_on_small_panel_is_detected(self):
+        # A coordinate meant for a wide build (x past 64) must still be caught
+        # when the declared panel is only 64 wide.
+        dm = BoundsCheckingDisplayManager(width=64, height=32)
+        dm.draw.rectangle([200, 5, 210, 10], fill=(255, 0, 0))
+        bbox = dm.check_overflow()
+        assert bbox is not None
+        assert bbox[0] >= 64
+
+    def test_in_bounds_drawing_has_no_overflow(self):
+        dm = BoundsCheckingDisplayManager(width=64, height=32)
+        dm.draw.rectangle([0, 0, 63, 31], fill=(255, 255, 255))
+        assert dm.check_overflow() is None
+
+    def test_right_overflow_is_detected(self):
+        dm = BoundsCheckingDisplayManager(width=64, height=32)
+        # Draw a few pixels past the right edge.
+        dm.draw.rectangle([60, 5, 70, 10], fill=(255, 0, 0))
+        bbox = dm.check_overflow()
+        assert bbox is not None
+        assert bbox[0] >= 64  # overflow starts at or past the declared width
+
+    def test_bottom_overflow_is_detected(self):
+        dm = BoundsCheckingDisplayManager(width=64, height=32)
+        dm.draw.rectangle([5, 30, 10, 40], fill=(0, 255, 0))
+        bbox = dm.check_overflow()
+        assert bbox is not None
+        assert bbox[3] > 32  # overflow extends past the declared height
+
+    def test_declared_image_is_cropped_to_panel(self):
+        dm = BoundsCheckingDisplayManager(width=64, height=32)
+        assert dm.get_image().size == (64, 32)
+
+    def test_snapshot_saves_cropped_panel(self, tmp_path):
+        dm = BoundsCheckingDisplayManager(width=128, height=32)
+        out = tmp_path / "snap.png"
+        dm.save_snapshot(str(out))
+        with Image.open(out) as img:
+            assert img.size == (128, 32)
+
+
+class TestArbitraryPanelSizes:
+    """The harness must handle any panel shape, not a fixed supported list."""
+
+    def test_overflow_extent_pads_to_largest_in_run(self):
+        # A wide run (extent 256) means content at x=200 on a 64-wide panel is
+        # caught; the same draw with a small extent would be clipped (false pass).
+        wide = BoundsCheckingDisplayManager(width=64, height=32, overflow_extent=(256, 32))
+        wide.draw.rectangle([200, 5, 210, 10], fill=(255, 0, 0))
+        assert wide.check_overflow() is not None
+
+        tight = BoundsCheckingDisplayManager(width=64, height=32, overflow_extent=(64, 32))
+        tight.draw.rectangle([200, 5, 210, 10], fill=(255, 0, 0))
+        assert tight.check_overflow() is None  # clipped beyond the small canvas
+
+    def test_unusual_shapes_report_their_declared_size(self):
+        for w, h in [(8, 2), (6, 6), (200, 8), (64, 96)]:
+            dm = BoundsCheckingDisplayManager(width=w, height=h)
+            assert dm.width == w and dm.height == h
+            assert dm.matrix.width == w and dm.matrix.height == h
+
+
+class TestUpdateErrorClassification:
+    """update() may fail for lack of network (tolerated) but a logic bug must
+    not pass green just because display() survives."""
+
+    def test_connectivity_errors_are_tolerated(self):
+        import socket
+        import urllib.error
+        for exc in (ConnectionError("x"), TimeoutError("x"), socket.gaierror("x"),
+                    urllib.error.URLError("x")):
+            assert isinstance(exc, _TOLERATED_UPDATE_ERRORS)
+
+    def test_logic_errors_are_not_tolerated(self):
+        for exc in (ValueError("x"), KeyError("x"), AttributeError("x"), TypeError("x")):
+            assert not isinstance(exc, _TOLERATED_UPDATE_ERRORS)
+
+
+class TestSizeParsing:
+    def test_parse_size_token_ok(self):
+        assert parse_size_token(" 128X32 ") == (128, 32)
+
+    def test_parse_size_token_rejects_garbage(self):
+        with pytest.raises(ValueError):
+            parse_size_token("128xabc")
+        with pytest.raises(ValueError):
+            parse_size_token("128-32")
+
+    def test_rejects_non_positive_dimensions(self):
+        for bad in ("0x32", "-64x32", "64x0", "64x-1"):
+            with pytest.raises(ValueError):
+                parse_size_token(bad)
+        with pytest.raises(ValueError):
+            coerce_sizes([[0, 32]])
+        with pytest.raises(ValueError):
+            coerce_sizes("64x-1")
+
+    def test_coerce_sizes_from_string_and_pairs(self):
+        assert coerce_sizes("8x16,64x64") == [(8, 16), (64, 64)]
+        assert coerce_sizes([[8, 16], (64, 64)]) == [(8, 16), (64, 64)]
+        assert coerce_sizes(None) is None
+        assert coerce_sizes("") is None
+
+    def test_resolve_precedence_env_then_spec_then_default(self, monkeypatch):
+        monkeypatch.delenv("LEDMATRIX_TEST_SIZES", raising=False)
+        assert resolve_test_sizes(None) == list(DEFAULT_TEST_SIZES)
+        assert resolve_test_sizes([[8, 16]]) == [(8, 16)]
+        monkeypatch.setenv("LEDMATRIX_TEST_SIZES", "5x5")
+        # env wins over a per-plugin spec
+        assert resolve_test_sizes([[8, 16]]) == [(5, 5)]
+
+
+class TestCompareImages:
+    def test_identical_images_match(self):
+        a = Image.new("RGB", (16, 16), (10, 20, 30))
+        b = a.copy()
+        ok, diff_pixels, max_delta = compare_images(a, b)
+        assert ok and diff_pixels == 0 and max_delta == 0
+
+    def test_different_images_fail_at_zero_tolerance(self):
+        a = Image.new("RGB", (16, 16), (0, 0, 0))
+        b = a.copy()
+        b.putpixel((1, 1), (255, 255, 255))
+        ok, diff_pixels, max_delta = compare_images(a, b)
+        assert not ok and diff_pixels == 1 and max_delta == 255
+
+    def test_tolerance_absorbs_small_noise(self):
+        a = Image.new("RGB", (16, 16), (100, 100, 100))
+        b = a.copy()
+        b.putpixel((2, 2), (103, 100, 100))  # delta 3
+        ok, _, max_delta = compare_images(a, b, max_delta=5, max_diff_pixels=0)
+        assert ok and max_delta == 3
+
+    def test_size_mismatch_fails(self):
+        a = Image.new("RGB", (16, 16))
+        b = Image.new("RGB", (32, 16))
+        ok, _, _ = compare_images(a, b)
+        assert not ok
+
+
+class TestListModes:
+    def test_instance_modes_take_precedence(self):
+        inst = type("P", (), {"modes": ["a", "b"]})()
+        assert list_modes(inst, {"display_modes": ["x"]}, "pid") == ["a", "b"]
+
+    def test_falls_back_to_manifest_display_modes(self):
+        inst = type("P", (), {})()
+        assert list_modes(inst, {"display_modes": ["x", "y"]}, "pid") == ["x", "y"]
+
+    def test_falls_back_to_plugin_id(self):
+        inst = type("P", (), {})()
+        assert list_modes(inst, {}, "pid") == ["pid"]
+
+
+def _load_check_plugin_cli():
+    """Load scripts/check_plugin.py by path (it isn't an importable package)."""
+    root = Path(__file__).resolve().parents[2]
+    path = root / "scripts" / "check_plugin.py"
+    spec = importlib.util.spec_from_file_location("check_plugin_cli", path)
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+    return mod
+
+
+def _make_fixture_plugin(tmp_path, harness):
+    """Create a minimal plugin dir with a test/harness.json; return its parent
+    (the search dir)."""
+    pdir = tmp_path / "plugins" / "demo-clock"
+    (pdir / "test").mkdir(parents=True)
+    (pdir / "manifest.json").write_text(json.dumps({
+        "id": "demo-clock", "name": "Demo Clock", "version": "1.0.0",
+        "author": "test", "entry_point": "manager.py", "class_name": "DemoClock",
+        "display_modes": ["demo-clock"], "compatible_versions": ["*"],
+    }))
+    (pdir / "test" / "harness.json").write_text(json.dumps(harness))
+    return pdir.parent
+
+
+class TestCheckPluginHonorsHarnessJson:
+    """Regression: check_plugin.py (the CI tool) must apply test/harness.json so
+    its render reproduces the committed goldens — otherwise time/data-dependent
+    plugins drift on every CI run."""
+
+    def test_harness_json_supplies_render_settings(self, tmp_path, monkeypatch):
+        mod = _load_check_plugin_cli()
+        search = _make_fixture_plugin(tmp_path, {
+            "config": {"timezone": "UTC"},
+            "freeze_time": "2025-08-01 15:25:00",
+            "sizes": [[128, 32]],
+        })
+        captured = {}
+        monkeypatch.setattr(mod, "render_plugin_matrix",
+                            lambda **kw: captured.update(kw) or [])
+        monkeypatch.setattr(mod, "compare_to_goldens", lambda *a, **k: [])
+        mod.check_one(
+            plugin_id="demo-clock", search_dirs=[str(search)], sizes=None,
+            mock_data={}, config={}, run_update=True, out_dir=None,
+            update_golden=False, golden_dir_override=None, freeze_time=None,
+        )
+        assert captured["freeze_time"] == "2025-08-01 15:25:00"
+        assert captured["config"]["timezone"] == "UTC"
+        assert captured["sizes"] == [(128, 32)]
+
+    def test_cli_flags_override_harness_json(self, tmp_path, monkeypatch):
+        mod = _load_check_plugin_cli()
+        search = _make_fixture_plugin(tmp_path, {
+            "config": {"timezone": "UTC"},
+            "freeze_time": "2025-08-01 15:25:00",
+        })
+        captured = {}
+        monkeypatch.setattr(mod, "render_plugin_matrix",
+                            lambda **kw: captured.update(kw) or [])
+        monkeypatch.setattr(mod, "compare_to_goldens", lambda *a, **k: [])
+        mod.check_one(
+            plugin_id="demo-clock", search_dirs=[str(search)], sizes=None,
+            mock_data={}, config={"timezone": "America/New_York"},
+            run_update=True, out_dir=None, update_golden=False,
+            golden_dir_override=None, freeze_time="2030-01-01 00:00:00",
+        )
+        assert captured["freeze_time"] == "2030-01-01 00:00:00"
+        assert captured["config"]["timezone"] == "America/New_York"

test/plugins/test_plugin_matrix.py

@@ -0,0 +1,115 @@
+"""
+Cross-size / cross-screen plugin safety test.
+
+For every discovered plugin, render every declared screen at every supported
+matrix size and assert it: loads, renders without crashing, stays within the
+panel bounds, and — for plugins that ship golden images — matches them.
+
+Plugin discovery (first match wins):
+  - $LEDMATRIX_PLUGINS_DIR  (os.pathsep-separated list of dirs), else
+  - <project_root>/plugin-repos and <project_root>/plugins
+
+A plugin opts into golden-image checks by adding test/golden/<WxH>/<mode>.png
+(and usually test/harness.json for deterministic config / mock data / time).
+"""
+
+import os
+from pathlib import Path
+from typing import Dict, List
+
+import pytest
+
+from src.plugin_system.testing.harness import (
+    render_plugin_matrix, compare_to_goldens,
+)
+from src.plugin_system.testing.loading import load_config_defaults, load_harness_spec
+from src.plugin_system.testing.sizes import resolve_test_sizes
+
+PROJECT_ROOT = Path(__file__).resolve().parents[2]
+
+# Set LEDMATRIX_REQUIRE_PLUGINS=1 in any CI/hardware pipeline where plugins are
+# expected to be present, so a discovery drift (empty search path) fails loudly
+# instead of silently skipping and losing this safety signal.
+_REQUIRE_PLUGINS = os.environ.get("LEDMATRIX_REQUIRE_PLUGINS") == "1"
+
+
+def _plugin_search_dirs() -> List[Path]:
+    env = os.environ.get("LEDMATRIX_PLUGINS_DIR")
+    if env:
+        return [Path(p) for p in env.split(os.pathsep) if p]
+    return [PROJECT_ROOT / "plugin-repos", PROJECT_ROOT / "plugins"]
+
+
+def _discover() -> Dict[str, Path]:
+    """Map plugin_id -> plugin_dir for all plugins on the search path."""
+    found: Dict[str, Path] = {}
+    for base in _plugin_search_dirs():
+        if not base.exists():
+            continue
+        for child in sorted(base.iterdir()):
+            if (child / "manifest.json").exists() and child.name not in found:
+                found[child.name] = child
+    return found
+
+
+_PLUGINS = _discover()
+
+
+@pytest.mark.plugin
+def test_plugins_were_discovered() -> None:
+    """Guard against silently skipping the whole matrix when discovery drifts.
+
+    Local dev and the plugin-less core CI legitimately have no plugins, so we
+    skip there; but when LEDMATRIX_REQUIRE_PLUGINS=1 an empty search path is a
+    hard failure rather than a green no-op.
+    """
+    if _PLUGINS:
+        return
+    search = [str(p) for p in _plugin_search_dirs()]
+    if _REQUIRE_PLUGINS:
+        pytest.fail(
+            "LEDMATRIX_REQUIRE_PLUGINS=1 but no plugins were discovered on the "
+            f"search path: {search}"
+        )
+    pytest.skip(f"no plugins found on the search path: {search}")
+
+
+@pytest.mark.plugin
+@pytest.mark.skipif(not _PLUGINS, reason="no plugins found on the search path")
+@pytest.mark.parametrize("plugin_id", sorted(_PLUGINS))
+def test_plugin_renders_across_sizes_and_screens(plugin_id: str) -> None:
+    plugin_dir = _PLUGINS[plugin_id]
+    spec = load_harness_spec(plugin_dir)
+
+    config = {"enabled": True}
+    config.update(load_config_defaults(plugin_dir))
+    config.update(spec.get("config", {}))
+
+    # Sizes: LEDMATRIX_TEST_SIZES env (test on real hardware) wins, then the
+    # plugin's own harness.json "sizes", else the default representative sample.
+    sizes = resolve_test_sizes(spec.get("sizes"))
+
+    results = render_plugin_matrix(
+        plugin_id=plugin_id,
+        plugin_dir=plugin_dir,
+        config=config,
+        mock_data=spec.get("mock_data_contents", {}),
+        sizes=sizes,
+        run_update=not spec.get("skip_update", False),
+        freeze_time=spec.get("freeze_time"),
+    )
+    compare_to_goldens(results, plugin_dir / "test" / "golden")
+
+    failures = []
+    for r in results:
+        if r.error is not None:
+            failures.append(f"{r.size_label} {r.mode}: crashed: {r.error}")
+        elif r.overflow is not None:
+            failures.append(f"{r.size_label} {r.mode}: overflow past panel bbox={r.overflow}")
+        elif r.golden_checked and r.golden_ok is False:
+            failures.append(
+                f"{r.size_label} {r.mode}: golden drift {r.golden_diff_pixels}px "
+                f"(max Δ={r.golden_max_delta})"
+            )
+
+    assert not failures, f"{plugin_id} failed:\n  " + "\n  ".join(failures)

test/test_display_controller.py

@@ -214,6 +214,104 @@ class TestDisplayControllerLivePriority:
         assert controller.current_mode_index == 1
         assert controller.current_display_mode == "b"
 
+    # --- Round-robin between multiple simultaneous live games --------------
+
+    @staticmethod
+    def _live_plugin(live_modes):
+        """A mock plugin that is live and reports the given live mode names."""
+        p = MagicMock()
+        p.has_live_priority = MagicMock(return_value=True)
+        p.has_live_content = MagicMock(return_value=True)
+        p.get_live_modes = MagicMock(return_value=list(live_modes))
+        return p
+
+    def test_collect_live_modes_dedupes_multi_mode_plugin(self, test_display_controller):
+        """A sports plugin registered under several mode keys (one per league)
+        contributes each live mode once, in registration order; plugins with no
+        live content are skipped."""
+        controller = test_display_controller
+        baseball = self._live_plugin(["baseball_live"])
+        soccer = self._live_plugin(["soccer_fifa.world_live"])
+        idle = MagicMock()
+        idle.has_live_priority = MagicMock(return_value=True)
+        idle.has_live_content = MagicMock(return_value=False)
+        controller.plugin_modes = {
+            "baseball_live": baseball,
+            "baseball_recent": baseball,
+            "soccer_fifa.world_live": soccer,
+            "soccer_usa.1_live": soccer,
+            "soccer_recent": soccer,
+            "clock": idle,
+        }
+        assert controller._collect_live_modes() == [
+            "baseball_live", "soccer_fifa.world_live"
+        ]
+
+    def test_round_robin_alternates_between_simultaneous_live_games(self, test_display_controller):
+        """Regression: with two games live at once, the live-priority pick
+        round-robins each dwell instead of pinning to the first plugin in
+        registration order (the bug where a baseball game hid a live World Cup
+        match)."""
+        controller = test_display_controller
+        baseball = self._live_plugin(["baseball_live"])
+        soccer = self._live_plugin(["soccer_fifa.world_live"])
+        controller.plugin_modes = {
+            "baseball_live": baseball,
+            "soccer_fifa.world_live": soccer,
+        }
+        # First entry into live priority from an ambient mode -> first live game.
+        controller.current_display_mode = "clock"
+        assert controller._check_live_priority(advance=True) == "baseball_live"
+        # The controller switches to it; the next dwell advances to the other.
+        controller.current_display_mode = "baseball_live"
+        assert controller._check_live_priority(advance=True) == "soccer_fifa.world_live"
+        # And wraps back again.
+        controller.current_display_mode = "soccer_fifa.world_live"
+        assert controller._check_live_priority(advance=True) == "baseball_live"
+
+    def test_single_live_game_holds_without_flipping(self, test_display_controller):
+        """One live game: advancing returns the same mode, so the hold is stable."""
+        controller = test_display_controller
+        controller.plugin_modes = {"baseball_live": self._live_plugin(["baseball_live"])}
+        controller.current_display_mode = "baseball_live"
+        assert controller._check_live_priority(advance=True) == "baseball_live"
+
+    def test_non_advancing_peek_does_not_rotate(self, test_display_controller):
+        """The default (advance=False) peek used by the Vegas coordinator must
+        not spin the cursor: it returns the live mode already on screen."""
+        controller = test_display_controller
+        controller.plugin_modes = {
+            "baseball_live": self._live_plugin(["baseball_live"]),
+            "soccer_fifa.world_live": self._live_plugin(["soccer_fifa.world_live"]),
+        }
+        controller.current_display_mode = "soccer_fifa.world_live"
+        assert controller._check_live_priority() == "soccer_fifa.world_live"
+        assert controller._check_live_priority() == "soccer_fifa.world_live"
+        # From an ambient mode the peek reports the first live game (truthy).
+        controller.current_display_mode = "clock"
+        assert controller._check_live_priority() == "baseball_live"
+
+    def test_no_live_content_returns_none(self, test_display_controller):
+        controller = test_display_controller
+        idle = MagicMock()
+        idle.has_live_priority = MagicMock(return_value=True)
+        idle.has_live_content = MagicMock(return_value=False)
+        controller.plugin_modes = {"clock": idle}
+        controller.current_display_mode = "clock"
+        assert controller._check_live_priority(advance=True) is None
+
+    def test_fallback_to_mode_name_when_get_live_modes_unhelpful(self, test_display_controller):
+        """A live plugin whose get_live_modes returns nothing registered falls
+        back to its own '_live' mode name (legacy behavior preserved)."""
+        controller = test_display_controller
+        legacy = MagicMock()
+        legacy.has_live_priority = MagicMock(return_value=True)
+        legacy.has_live_content = MagicMock(return_value=True)
+        legacy.get_live_modes = MagicMock(return_value=["unregistered_mode"])
+        controller.plugin_modes = {"hockey_live": legacy}
+        controller.current_display_mode = "clock"
+        assert controller._check_live_priority(advance=True) == "hockey_live"
+
 
 class TestDisplayControllerDynamicDuration:
     """Test dynamic duration handling."""

test/test_store_manager_caches.py

@@ -43,6 +43,115 @@ class TestUninstallTombstone(unittest.TestCase):
         self.assertNotIn("foo", self.sm._uninstall_tombstones)
 
 
+class TestPersistentUninstallRegistry(unittest.TestCase):
+    """Regression tests for the persistent uninstall registry that stops a
+    core `git pull` update from resurrecting built-in plugins the user
+    removed (plugins committed under plugin-repos/)."""
+
+    def setUp(self):
+        self._tmp = TemporaryDirectory()
+        self.addCleanup(self._tmp.cleanup)
+        self.plugins_dir = Path(self._tmp.name) / "plugin-repos"
+        self.plugins_dir.mkdir()
+        self.registry_path = Path(self._tmp.name) / "config" / "uninstalled_plugins.json"
+        self.sm = PluginStoreManager(
+            plugins_dir=str(self.plugins_dir),
+            uninstalled_registry_path=str(self.registry_path),
+        )
+
+    def _make_plugin_dir(self, plugin_id):
+        """Simulate a built-in plugin restored on disk (e.g. by git pull)."""
+        d = self.plugins_dir / plugin_id
+        d.mkdir(parents=True)
+        (d / "manifest.json").write_text('{"id": "%s"}' % plugin_id)
+        return d
+
+    def test_unrecorded_plugin_is_not_uninstalled(self):
+        self.assertFalse(self.sm.is_plugin_uninstalled("web-ui-info"))
+        self.assertEqual(self.sm.get_uninstalled_plugins(), set())
+
+    def test_record_persists_across_instances(self):
+        self.sm.record_uninstalled_plugin("web-ui-info")
+        self.assertTrue(self.registry_path.exists())
+        # A fresh manager (simulating a service restart after update) still sees it.
+        fresh = PluginStoreManager(
+            plugins_dir=str(self.plugins_dir),
+            uninstalled_registry_path=str(self.registry_path),
+        )
+        self.assertTrue(fresh.is_plugin_uninstalled("web-ui-info"))
+
+    def test_forget_clears_record(self):
+        self.sm.record_uninstalled_plugin("web-ui-info")
+        self.sm.forget_uninstalled_plugin("web-ui-info")
+        self.assertFalse(self.sm.is_plugin_uninstalled("web-ui-info"))
+
+    def test_purge_removes_resurrected_plugin(self):
+        # The bug: user removed web-ui-info, then a git pull restored its
+        # committed files. Recorded uninstall + purge must re-remove it.
+        self._make_plugin_dir("web-ui-info")
+        self.sm.record_uninstalled_plugin("web-ui-info")
+        self.assertTrue((self.plugins_dir / "web-ui-info").exists())
+
+        removed = self.sm.purge_uninstalled_plugins()
+
+        self.assertEqual(removed, ["web-ui-info"])
+        self.assertFalse((self.plugins_dir / "web-ui-info").exists())
+        # Record is kept so the purge stays idempotent across future updates.
+        self.assertTrue(self.sm.is_plugin_uninstalled("web-ui-info"))
+
+    def test_purge_leaves_non_uninstalled_plugins_alone(self):
+        self._make_plugin_dir("baseball-scoreboard")  # present, not recorded
+        self._make_plugin_dir("web-ui-info")
+        self.sm.record_uninstalled_plugin("web-ui-info")
+
+        self.sm.purge_uninstalled_plugins()
+
+        self.assertTrue((self.plugins_dir / "baseball-scoreboard").exists())
+        self.assertFalse((self.plugins_dir / "web-ui-info").exists())
+
+    def test_purge_noop_when_plugin_absent(self):
+        # Recorded but never restored on disk — nothing to remove.
+        self.sm.record_uninstalled_plugin("web-ui-info")
+        self.assertEqual(self.sm.purge_uninstalled_plugins(), [])
+
+    def test_corrupt_registry_is_ignored(self):
+        self.registry_path.parent.mkdir(parents=True, exist_ok=True)
+        self.registry_path.write_text("{ not valid json")
+        self.assertEqual(self.sm.get_uninstalled_plugins(), set())
+        self.assertFalse(self.sm.is_plugin_uninstalled("web-ui-info"))
+
+    def _write_raw_registry(self, value):
+        self.registry_path.parent.mkdir(parents=True, exist_ok=True)
+        import json as _json
+        self.registry_path.write_text(_json.dumps(value))
+
+    def test_empty_id_does_not_wipe_plugins_root(self):
+        # An empty id resolves to plugins_dir itself; purge must never delete it.
+        self._make_plugin_dir("baseball-scoreboard")
+        self._write_raw_registry([""])
+
+        removed = self.sm.purge_uninstalled_plugins()
+
+        self.assertEqual(removed, [])
+        self.assertTrue(self.plugins_dir.exists())
+        self.assertTrue((self.plugins_dir / "baseball-scoreboard").exists())
+        # Invalid id is filtered out entirely.
+        self.assertEqual(self.sm.get_uninstalled_plugins(), set())
+
+    def test_traversal_ids_are_ignored(self):
+        for bad in ["..", "../evil", "a/b", "."]:
+            with self.subTest(bad=bad):
+                self.assertFalse(self.sm._is_valid_plugin_id(bad))
+        self._write_raw_registry(["../evil", "..", "web-ui-info"])
+        # Only the safe id survives the read.
+        self.assertEqual(self.sm.get_uninstalled_plugins(), {"web-ui-info"})
+
+    def test_record_rejects_invalid_id(self):
+        self.sm.record_uninstalled_plugin("")
+        self.sm.record_uninstalled_plugin("../escape")
+        self.assertEqual(self.sm.get_uninstalled_plugins(), set())
+
+
 class TestGitInfoCache(unittest.TestCase):
     def setUp(self):
         self._tmp = TemporaryDirectory()

test/web_interface/test_dotted_league_keys.py

@@ -0,0 +1,93 @@
+"""
+Regression test for saving plugin config fields whose schema keys contain dots
+(e.g. soccer league keys like "fifa.world", "eng.1", "usa.1").
+
+Bug: the web config form posts form-data with dotted paths such as
+"leagues.fifa.world.enabled". The helpers that resolve those paths split on every
+dot, so the dotted league key "fifa.world" was mistaken for nested "fifa" ->
+"world" objects. Per-league edits (enable, favorite_teams, nested booleans) were
+written to a fabricated "leagues.fifa.world" branch while the real league object
+was never updated, so the save silently dropped the change and the saved config
+came out byte-identical.
+"""
+
+import unittest
+
+from web_interface.blueprints.api_v3 import (
+    _get_schema_property,
+    _set_nested_value,
+    _parse_form_value_with_schema,
+)
+
+
+SCHEMA = {
+    "type": "object",
+    "properties": {
+        "leagues": {
+            "type": "object",
+            "properties": {
+                "fifa.world": {
+                    "type": "object",
+                    "properties": {
+                        "enabled": {"type": "boolean"},
+                        "favorite_teams": {
+                            "type": "array",
+                            "items": {"type": "string"},
+                        },
+                        "display_modes": {
+                            "type": "object",
+                            "properties": {"live": {"type": "boolean"}},
+                        },
+                    },
+                }
+            },
+        }
+    },
+}
+
+
+class TestDottedLeagueKeys(unittest.TestCase):
+    def test_schema_lookup_resolves_dotted_league_key(self):
+        prop = _get_schema_property(SCHEMA, "leagues.fifa.world.favorite_teams")
+        self.assertIsNotNone(prop, "dotted league key path should resolve")
+        self.assertEqual(prop.get("type"), "array")
+
+    def test_schema_lookup_resolves_nested_object_beneath_dotted_key(self):
+        live = _get_schema_property(SCHEMA, "leagues.fifa.world.display_modes.live")
+        self.assertIsNotNone(live)
+        self.assertEqual(live.get("type"), "boolean")
+
+    def test_parse_typed_value_for_dotted_key(self):
+        # Comma-separated text input "USA" must become an array, not the raw string.
+        parsed = _parse_form_value_with_schema(
+            "USA", "leagues.fifa.world.favorite_teams", SCHEMA
+        )
+        self.assertEqual(parsed, ["USA"])
+
+    def test_set_value_updates_real_league_not_fabricated_branch(self):
+        config = {"leagues": {"fifa.world": {"enabled": False, "favorite_teams": []}}}
+        _set_nested_value(config, "leagues.fifa.world.enabled", True)
+        _set_nested_value(config, "leagues.fifa.world.favorite_teams", ["USA"])
+
+        self.assertTrue(config["leagues"]["fifa.world"]["enabled"])
+        self.assertEqual(config["leagues"]["fifa.world"]["favorite_teams"], ["USA"])
+        # The real league must be updated and no fabricated "fifa" branch created.
+        self.assertNotIn("fifa", config["leagues"])
+
+    def test_set_value_into_missing_leaf_lands_in_real_league(self):
+        # A leaf that does not exist yet still resolves into the real dotted league.
+        config = {"leagues": {"fifa.world": {"enabled": False}}}
+        _set_nested_value(config, "leagues.fifa.world.display_modes.live", True)
+        self.assertTrue(
+            config["leagues"]["fifa.world"]["display_modes"]["live"]
+        )
+        self.assertNotIn("fifa", config["leagues"])
+
+    def test_plain_nested_paths_still_work(self):
+        config = {}
+        _set_nested_value(config, "customization.text.font", "small")
+        self.assertEqual(config["customization"]["text"]["font"], "small")
+
+
+if __name__ == "__main__":
+    unittest.main()

web_interface/app.py

@@ -79,6 +79,21 @@ plugin_manager = PluginManager(
     cache_manager=None     # Not needed for web interface
 )
 plugin_store_manager = PluginStoreManager(plugins_dir=str(plugins_dir))
+# A core `git pull` update (or any checkout) restores built-in plugins
+# committed under plugin-repos/, even ones the user uninstalled. Re-remove any
+# the user previously uninstalled at startup so a manual update on the Pi
+# doesn't resurrect them.
+try:
+    _purged = plugin_store_manager.purge_uninstalled_plugins()
+    if _purged:
+        logging.getLogger(__name__).info(
+            "Re-removed %d uninstalled plugin(s) restored since last run: %s",
+            len(_purged), ", ".join(_purged),
+        )
+except (OSError, RuntimeError) as _purge_err:
+    logging.getLogger(__name__).warning(
+        "Startup plugin purge failed: %s", _purge_err
+    )
 saved_repositories_manager = SavedRepositoriesManager()
 
 # Initialize schema manager

web_interface/blueprints/api_v3.py

@@ -1559,6 +1559,20 @@ def execute_system_action():
                     pull_message = f"Code updated successfully. Local changes were automatically stashed.{stash_info}"
                 if result.stdout and "Already up to date" not in result.stdout:
                     pull_message = f"Code updated successfully.{stash_info}"
+                # A `git pull` restores built-in plugins (committed under
+                # plugin-repos/) even if the user uninstalled them. Re-remove
+                # any the user previously uninstalled so the update doesn't
+                # resurrect them.
+                if api_v3.plugin_store_manager:
+                    try:
+                        purged = api_v3.plugin_store_manager.purge_uninstalled_plugins()
+                        if purged:
+                            logger.info(
+                                "Re-removed %d uninstalled plugin(s) restored by update: %s",
+                                len(purged), ", ".join(purged),
+                            )
+                    except (OSError, RuntimeError) as purge_err:
+                        logger.warning("Post-update plugin purge failed: %s", purge_err)
             else:
                 logger.warning("git pull failed (returncode=%d): %s", result.returncode, result.stderr)
                 pull_message = "Update failed; check logs for details"
@@ -2933,6 +2947,13 @@ def _do_transactional_uninstall(plugin_id, preserve_config):
         api_v3.schema_manager.invalidate_cache(plugin_id)
     if api_v3.plugin_state_manager:
         api_v3.plugin_state_manager.remove_plugin_state(plugin_id)
+    # Persistently record the uninstall so a later core `git pull` update
+    # cannot resurrect a built-in plugin (committed under plugin-repos/) that
+    # the user removed. Best-effort: never fail the uninstall over this.
+    try:
+        api_v3.plugin_store_manager.record_uninstalled_plugin(plugin_id)
+    except Exception as record_err:
+        logger.warning("Could not record uninstall for %s: %s", plugin_id, record_err)
     return True, None
 
 
@@ -3537,21 +3558,29 @@ def _get_schema_property(schema, key_path):
 
     parts = key_path.split('.')
     current = schema['properties']
+    i = 0
 
-    for i, part in enumerate(parts):
+    while i < len(parts):
-        if part not in current:
+        # Try progressively longer candidates, longest first, so schema keys that
-            return None
+        # themselves contain dots (e.g. league keys like "fifa.world") are matched
-
+        # instead of being mistaken for nested "fifa" -> "world" objects.
-        prop = current[part]
+        matched = False
-
+        for j in range(len(parts), i, -1):
-        # If this is the last part, return the property
+            candidate = '.'.join(parts[i:j])
-        if i == len(parts) - 1:
+            if isinstance(current, dict) and candidate in current:
-            return prop
+                prop = current[candidate]
-
+                # Consumed all remaining parts — this is the target property.
-        # If this is an object with properties, navigate deeper
+                if j == len(parts):
-        if isinstance(prop, dict) and 'properties' in prop:
+                    return prop
-            current = prop['properties']
+                # Navigate deeper through an object with properties.
-        else:
+                if isinstance(prop, dict) and 'properties' in prop:
+                    current = prop['properties']
+                    i = j
+                    matched = True
+                    break
+                # Matched a non-object before consuming the path — can't go deeper.
+                return None
+        if not matched:
             return None
 
     return None
@@ -3724,10 +3753,45 @@ def _parse_form_value_with_schema(value, key_path, schema):
     return value
 
 
+def _resolve_key_segments(key_path, config):
+    """Split a dot-notation path into segments, greedily preserving keys that
+    themselves contain dots (e.g. league keys like "fifa.world").
+
+    At each level the longest candidate that matches a key already present in the
+    config wins; otherwise the path splits on the next dot (the normal
+    nested-create case). Because dotted keys such as ``leagues."fifa.world"``
+    always exist in the saved config being updated, this routes the value to the
+    real league object instead of fabricating a ``leagues.fifa.world`` tree.
+    """
+    parts = key_path.split('.')
+    segments = []
+    node = config
+    i = 0
+    while i < len(parts):
+        matched = False
+        if isinstance(node, dict):
+            for j in range(len(parts), i, -1):
+                candidate = '.'.join(parts[i:j])
+                if candidate in node:
+                    segments.append(candidate)
+                    node = node[candidate]
+                    i = j
+                    matched = True
+                    break
+        if not matched:
+            part = parts[i]
+            segments.append(part)
+            node = node.get(part) if isinstance(node, dict) else None
+            i += 1
+    return segments
+
+
 def _set_nested_value(config, key_path, value):
     """
     Set a value in a nested dict using dot notation path.
     Handles existing nested dicts correctly by merging instead of replacing.
+    Keys containing dots (e.g. league keys like "fifa.world") are preserved when
+    they already exist in the config rather than being split into nested objects.
 
     Args:
         config: The config dict to modify
@@ -3738,21 +3802,21 @@ def _set_nested_value(config, key_path, value):
     if value is _SKIP_FIELD:
         return
 
-    parts = key_path.split('.')
+    segments = _resolve_key_segments(key_path, config)
     current = config
 
     # Navigate/create intermediate dicts
-    for i, part in enumerate(parts[:-1]):
+    for seg in segments[:-1]:
-        if part not in current:
+        if seg not in current:
-            current[part] = {}
+            current[seg] = {}
-        elif not isinstance(current[part], dict):
+        elif not isinstance(current[seg], dict):
             # If the existing value is not a dict, replace it with a dict
-            current[part] = {}
+            current[seg] = {}
-        current = current[part]
+        current = current[seg]
 
     # Set the final value (don't overwrite with empty dict if value is None and we want to preserve structure)
-    if value is not None or parts[-1] not in current:
+    if value is not None or segments[-1] not in current:
-        current[parts[-1]] = value
+        current[segments[-1]] = value
 
 
 def _set_missing_booleans_to_false(config, schema_props, form_keys, prefix='', config_node=None):

web_interface/templates/v3/partials/display.html

@@ -68,7 +68,7 @@
                            name="chain_length"
                            value="{{ main_config.display.hardware.chain_length or 2 }}"
                            min="1"
-                           max="8"
+                           max="24"
                            class="form-control">
                     <p class="mt-1 text-sm text-gray-600">Number of LED panels chained together</p>
                 </div>