diff --git a/.gitignore b/.gitignore
index b111ed7..184bbc3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,20 @@
-install-prefix/
+# Build artifacts
 build/
+bridge/build/
+install-prefix/
+
+# Python
+__pycache__/
+.pytest_cache/
+*.pyc
+*.pyo
+*.egg-info/
+venv/
+.venv/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..f992a5f
--- /dev/null
+++ b/README.md
@@ -0,0 +1,110 @@
+# QML SceneGraph MCP Bridge
+
+A [MCP](https://modelcontextprotocol.io/) server that bridges [GammaRay](https://github.com/KDAB/GammaRay) probe introspection data into MCP tools, enabling LLMs to inspect and debug Qt Quick / QML scene graphs, items, geometry, and materials.
+
+## Architecture
+
+```
+Target Qt/QML App  ──TCP──►  GammaRay MCP Bridge  ──stdio──►  LLM / AI Agent
+  (GammaRay probe                (GammaRay client +               (opencode,
+   injected)                      qtmcp MCP server)                Claude Desktop, etc.)
+```
+
+The bridge is a GammaRay **client**: it connects to a probe injected into a target Qt/QML app, reads the same models the GammaRay GUI uses, and translates them into MCP JSON-RPC tool calls over stdio.
+
+## Prerequisites
+
+- Qt 6.8+ (system)
+- C++20 compiler (GCC 12+, Clang 16+)
+- GammaRay 3.4.0+ built from source (see [build instructions](#building-gammaray))
+- [qtmcp](https://github.com/signal-slot/qtmcp) (consumed via FetchContent — no manual install)
+- Python 3.10+ with `pytest` (for running the test suite)
+
+## Building
+
+### 1. Build and install GammaRay
+
+```bash
+cmake -S /path/to/GammaRay -B /path/to/GammaRay/build \
+  -DCMAKE_INSTALL_PREFIX=$(pwd)/install-prefix
+cmake --build /path/to/GammaRay/build
+cmake --install /path/to/GammaRay/build --prefix $(pwd)/install-prefix
+```
+
+### 2. Build the bridge
+
+```bash
+cd bridge
+cmake -S . -B build -G Ninja -DCMAKE_PREFIX_PATH=$(pwd)/../install-prefix
+cmake --build build
+```
+
+### 3. Run
+
+```bash
+# Start a probe (inject into a QML app)
+install-prefix/bin/gammaray --inject-only --listen tcp://127.0.0.1:11732 \
+  --injector preload /usr/lib/qt6/bin/qml /path/to/app.qml -platform offscreen
+
+# Start the bridge (stdio MCP server)
+./run.sh
+```
+
+The bridge starts in lazy-connect mode. Call `connectProbe("127.0.0.1", 11732)` from your MCP client once the probe is up.
+
+## MCP Tools
+
+### Connection management
+| Tool | Description |
+|---|---|
+| `connectProbe(host, port)` | Connect to a GammaRay probe (defaults: 127.0.0.1:11732) |
+| `connectProbeDefault()` | Convenience: connect to 127.0.0.1:11732 |
+| `disconnectProbe()` | Drop connection and forget URL |
+| `probeStatus()` | Report connection state |
+
+### Navigation
+| Tool | Description |
+|---|---|
+| `listQuickWindows()` | List QQuickWindows in the target app |
+| `selectQuickWindow(index)` | Select a window for scene graph introspection |
+| `listQuickItems()` | Recursive QQuickItem tree with types and flags |
+| `listScenegraphNodes()` | Recursive QSGNode tree (all node types) |
+
+### QML Item inspection
+| Tool | Description |
+|---|---|
+| `selectQuickItem(address)` | Select a QML item by address, populating its properties model |
+| `getItemProperties(address)` | Get all Q_PROPERTY values (x, y, width, height, opacity, visible, z, anchors, text, font, etc.) |
+
+### SG Node inspection
+| Tool | Description |
+|---|---|
+| `selectScenegraphNode(address)` | Select a SG node, populating geometry/material sub-models |
+| `getNodeVertices(address)` | Read vertex data of a GeometryNode |
+| `getNodeAdjacency(address)` | Read adjacency/drawing mode of a GeometryNode |
+| `getMaterialShaders(address)` | List shader stages for a node's material |
+| `getShaderSource(row)` | Get shader source code (async via MaterialExtensionInterface) |
+| `getMaterialProperties(address)` | Get material property name/value pairs |
+
+### Rendering visualization
+| Tool | Description |
+|---|---|
+| `setRenderMode(mode)` | Set render mode (NormalRendering, VisualizeOverdraw, etc.) |
+| `setSlowMode(enabled)` | Toggle continuous rendering |
+
+## Testing
+
+```bash
+# Unit tests only (no probe needed):
+./tests/run_tests.sh --no-probe
+
+# Full integration test suite (probe required):
+./tests/run_tests.sh --no-probe  # skips probe-dependent tests
+./tests/run_tests.sh -v          # verbose
+```
+
+See `tests/README.md` for details.
+
+## License
+
+GPL-2.0-or-later. The bridge links GammaRay libraries (GPL-2.0-or-later) and uses qtmcp (available under GPL-2.0-only).
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..9ee3545
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,7 @@
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+python_files = ["test_*.py"]
+markers = [
+    "probe: tests that require a running GammaRay probe",
+]
+filterwarnings = ["ignore::DeprecationWarning"]
\ No newline at end of file
diff --git a/tests/README.md b/tests/README.md
new file mode 100644
index 0000000..55e182f
--- /dev/null
+++ b/tests/README.md
@@ -0,0 +1,55 @@
+# Test Suite
+
+Integration tests for the gammaray-mcp bridge, written in Python using `pytest`. Tests communicate with the bridge over stdio JSON-RPC (the same protocol MCP clients use), exercising every tool end-to-end against a real GammaRay probe.
+
+## Prerequisites
+
+- The bridge must be built: `cmake --build bridge/build`
+- `pytest` (install via `pip3 install pytest` or `pip install pytest` in a venv)
+- For probe-dependent tests: a QML test app at `~/Sources/testqml/relayout.qml` (configurable via `TEST_QML` env)
+
+## Running
+
+```bash
+# From the project root:
+./tests/run_tests.sh --no-probe    # unit tests only (no probe needed)
+./tests/run_tests.sh -v            # full suite, verbose
+./tests/run_tests.sh -k "item"     # run only item-related tests
+./tests/run_tests.sh --no-probe -x # stop on first failure, no probe
+```
+
+Or directly with pytest:
+
+```bash
+cd tests
+LD_LIBRARY_PATH=../install-prefix/lib \
+QT_QPA_PLATFORM=offscreen \
+QT_PLUGIN_PATH=../bridge/build/lib/x86_64-linux-gnu/qt6/plugins \
+pytest -v
+```
+
+## Test files
+
+| File | Tests | Probe required |
+|---|---|---|
+| `test_connection.py` | `connectProbe`, `probeStatus`, `disconnectProbe`, reconnect | Yes (except `test_tools_listed`, `test_probe_status_disconnected`) |
+| `test_navigation.py` | `listQuickWindows`, `selectQuickWindow`, `listQuickItems`, `listScenegraphNodes` | Yes |
+| `test_items.py` | `selectQuickItem`, `getItemProperties`, position, visual properties, groups | Yes |
+| `test_scenegraph.py` | `selectScenegraphNode`, `getNodeVertices`, `getNodeAdjacency`, `getMaterialShaders`, `getMaterialProperties`, `setRenderMode`, `setSlowMode` | Yes |
+
+## Markers
+
+- `@pytest.mark.probe` — test requires a running GammaRay probe. Automatically skipped with `--no-probe`.
+
+## Fixtures
+
+- `bridge` — fresh `McpClient` instance per test (initialized, not connected)
+- `connected_bridge` — bridge connected to a probe (via `connectProbeDefault`)
+- `probe_process` — session-scoped, starts a probe via `systemd-run` (fallback: direct spawn) and waits for `ready()`
+
+## Options
+
+| Flag | Default | Description |
+|---|---|---|
+| `--no-probe` | `false` | Skip all probe-dependent tests |
+| `--probe-timeout` | 15s | Seconds to wait for probe to become ready |
\ No newline at end of file
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..28453af
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1 @@
+# gammaray-mcp test suite
\ No newline at end of file
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..bf835e0
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,170 @@
+"""pytest fixtures for gammaray-mcp bridge tests."""
+
+import os
+import subprocess
+import time
+from pathlib import Path
+
+import pytest
+
+from mcp_client import McpClient
+
+PROJECT_ROOT = Path(__file__).resolve().parent.parent
+BRIDGE_EXE = PROJECT_ROOT / "bridge" / "build" / "qml-sg-mcp-bridge"
+RUN_SCRIPT = PROJECT_ROOT / "bridge" / "run.sh"
+PROBE_BIN = PROJECT_ROOT / "install-prefix" / "bin" / "gammaray"
+TEST_QML = Path(os.environ.get("TEST_QML", str(Path.home() / "Sources" / "testqml" / "relayout.qml")))
+QML_RUNNER = "/usr/lib/qt6/bin/qml"
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--no-probe",
+        action="store_true",
+        default=False,
+        help="Skip tests that need a running probe",
+    )
+    parser.addoption(
+        "--probe-timeout",
+        type=int,
+        default=15,
+        help="Seconds to wait for probe to be ready",
+    )
+
+
+def pytest_collection_modifyitems(config, items):
+    if config.getoption("--no-probe"):
+        skip_probe = pytest.mark.skip(reason="Skipping probe-dependent tests (--no-probe)")
+        for item in items:
+            if "probe" in item.keywords:
+                item.add_marker(skip_probe)
+
+
+@pytest.fixture(scope="session")
+def bridge_path() -> Path:
+    """Path to the bridge executable."""
+    if not BRIDGE_EXE.exists():
+        pytest.skip(f"Bridge not built at {BRIDGE_EXE}")
+    return BRIDGE_EXE
+
+
+@pytest.fixture(scope="session")
+def run_script_path() -> Path:
+    """Path to the run.sh wrapper."""
+    if not RUN_SCRIPT.exists():
+        pytest.skip(f"run.sh not found at {RUN_SCRIPT}")
+    return RUN_SCRIPT
+
+
+@pytest.fixture(scope="session")
+def probe_process(request) -> subprocess.Popen | None:
+    """Start a GammaRay probe process (session-scoped, one per test run)."""
+    if request.config.getoption("--no-probe"):
+        return None
+
+    if not PROBE_BIN.exists():
+        pytest.skip(f"GammaRay probe binary not found at {PROBE_BIN}")
+    if not TEST_QML.exists():
+        pytest.skip(f"Test QML file not found at {TEST_QML}")
+    if not QML_RUNNER.exists():
+        pytest.skip(f"QML runner not found at {QML_RUNNER}")
+
+    env = os.environ.copy()
+    env["QT_QPA_PLATFORM"] = "offscreen"
+    env["LD_LIBRARY_PATH"] = str(PROJECT_ROOT / "install-prefix" / "lib")
+
+    proc = None
+    used_systemd = False
+
+    # Try systemd-run first for clean detachment
+    subprocess.run(
+        ["systemctl", "--user", "stop", "gammaray-probe-test.service"],
+        capture_output=True, timeout=5,
+    )
+    subprocess.run(
+        ["systemctl", "--user", "reset-failed", "gammaray-probe-test.service"],
+        capture_output=True, timeout=5,
+    )
+
+    result = subprocess.run(
+        [
+            "systemd-run", "--user", "--no-block",
+            "--unit=gammaray-probe-test",
+            "--same-dir",
+            "--working-directory", str(TEST_QML.parent),
+            "-E", f"QT_QPA_PLATFORM={env['QT_QPA_PLATFORM']}",
+            "-E", f"LD_LIBRARY_PATH={env['LD_LIBRARY_PATH']}",
+            str(PROBE_BIN),
+            "--inject-only", "--listen", "tcp://127.0.0.1:11732",
+            "--injector", "preload",
+            QML_RUNNER, str(TEST_QML),
+        ],
+        capture_output=True, text=True, timeout=10,
+    )
+    if result.returncode == 0:
+        used_systemd = True
+    else:
+        # Fallback: direct spawn
+        proc = subprocess.Popen(
+            [str(PROBE_BIN), "--inject-only", "--listen", "tcp://127.0.0.1:11732",
+             "--injector", "preload", QML_RUNNER, str(TEST_QML)],
+            env=env, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
+        )
+
+    def cleanup():
+        if proc:
+            proc.terminate()
+            try:
+                proc.wait(timeout=5)
+            except subprocess.TimeoutExpired:
+                proc.kill()
+        if used_systemd:
+            subprocess.run(
+                ["systemctl", "--user", "stop", "gammaray-probe-test.service"],
+                capture_output=True, timeout=5,
+            )
+            subprocess.run(
+                ["systemctl", "--user", "reset-failed", "gammaray-probe-test.service"],
+                capture_output=True, timeout=5,
+            )
+
+    request.addfinalizer(cleanup)
+
+    # Wait for probe to be ready
+    timeout = request.config.getoption("--probe-timeout")
+    deadline = time.monotonic() + timeout
+    while time.monotonic() < deadline:
+        try:
+            c = McpClient(bridge_path=BRIDGE_EXE)
+            c.initialize()
+            result = c.call_tool("connectProbeDefault")
+            c.close()
+            if isinstance(result, dict) and result.get("connected"):
+                break
+        except Exception:
+            pass
+        time.sleep(1)
+    else:
+        pytest.fail(f"Probe did not become ready within {timeout}s")
+
+    return proc
+
+
+@pytest.fixture
+def bridge(run_script_path) -> McpClient:
+    """Start a fresh bridge instance per test."""
+    c = McpClient(bridge_path=run_script_path)
+    c.initialize()
+    yield c
+    c.close()
+
+
+@pytest.fixture
+def connected_bridge(bridge, probe_process) -> McpClient:
+    """Bridge connected to a running probe."""
+    if probe_process is None:
+        pytest.skip("No probe available")
+    result = bridge.call_tool("connectProbeDefault")
+    assert isinstance(result, dict), f"connectProbeDefault failed: {result}"
+    assert result.get("connected"), f"Not connected: {result}"
+    return bridge
\ No newline at end of file
diff --git a/tests/mcp_client.py b/tests/mcp_client.py
new file mode 100644
index 0000000..9e7f8ba
--- /dev/null
+++ b/tests/mcp_client.py
@@ -0,0 +1,90 @@
+"""MCP client helper for testing the gammaray-mcp bridge."""
+
+import json
+import subprocess
+import sys
+import time
+from pathlib import Path
+
+
+class McpClient:
+    """A minimal JSON-RPC MCP client communicating over stdio."""
+
+    def __init__(self, bridge_path: Path):
+        self._proc = subprocess.Popen(
+            [str(bridge_path)],
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            text=True,
+            bufsize=1,
+        )
+        self._next_id = 0
+        self._initialized = False
+
+    def close(self):
+        if self._proc and self._proc.poll() is None:
+            self._proc.terminate()
+            try:
+                self._proc.wait(timeout=5)
+            except subprocess.TimeoutExpired:
+                self._proc.kill()
+
+    @property
+    def stderr(self):
+        return self._proc.stderr
+
+    def send_request(self, method: str, params: dict | None = None) -> dict:
+        self._next_id += 1
+        req = {
+            "jsonrpc": "2.0",
+            "id": self._next_id,
+            "method": method,
+            "params": params or {},
+        }
+        line = json.dumps(req)
+        self._proc.stdin.write(line + "\n")
+        self._proc.stdin.flush()
+        return self._read_response(self._next_id)
+
+    def _read_response(self, expected_id: int, timeout: float = 60.0) -> dict:
+        deadline = time.monotonic() + timeout
+        while time.monotonic() < deadline:
+            line = self._proc.stdout.readline()
+            if not line:
+                raise RuntimeError("Bridge process terminated")
+            resp = json.loads(line)
+            rid = resp.get("id")
+            if rid == expected_id:
+                return resp
+            # Could be a notification; ignore and keep reading
+        raise TimeoutError(f"No response for id={expected_id} within {timeout}s")
+
+    def initialize(self, protocol_version: str = "2025-03-26") -> dict:
+        resp = self.send_request("initialize", {
+            "protocolVersion": protocol_version,
+            "capabilities": {},
+            "clientInfo": {"name": "test", "version": "1.0"},
+        })
+        # Send initialized notification
+        self._proc.stdin.write(
+            json.dumps({"jsonrpc": "2.0", "method": "notifications/initialized", "params": {}}) + "\n"
+        )
+        self._proc.stdin.flush()
+        self._initialized = True
+        return resp
+
+    def call_tool(self, name: str, arguments: dict | None = None) -> dict:
+        resp = self.send_request("tools/call", {"name": name, "arguments": arguments or {}})
+        content = resp.get("result", {}).get("content", [])
+        if content and content[0].get("type") == "text":
+            text = content[0]["text"]
+            try:
+                return json.loads(text)
+            except (json.JSONDecodeError, TypeError):
+                return {"_raw": text}
+        return resp.get("result", {})
+
+    def list_tools(self) -> list[dict]:
+        resp = self.send_request("tools/list")
+        return resp.get("result", {}).get("tools", [])
\ No newline at end of file
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
new file mode 100755
index 0000000..48768f7
--- /dev/null
+++ b/tests/run_tests.sh
@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+# Run the gammaray-mcp test suite.
+# Usage:
+#   ./run_tests.sh               # probe-required tests (default)
+#   ./run_tests.sh --no-probe    # only unit tests (no probe needed)
+#   ./run_tests.sh -v            # verbose
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+
+# Ensure the bridge is built
+if [ ! -f "$PROJECT_ROOT/bridge/build/qml-sg-mcp-bridge" ]; then
+    echo "Building bridge first..."
+    cmake -S "$PROJECT_ROOT/bridge" -B "$PROJECT_ROOT/bridge/build" -G Ninja \
+        -DCMAKE_PREFIX_PATH="$PROJECT_ROOT/install-prefix"
+    cmake --build "$PROJECT_ROOT/bridge/build"
+fi
+
+# Use the same env as run.sh
+export LD_LIBRARY_PATH="$PROJECT_ROOT/install-prefix/lib"
+export QT_QPA_PLATFORM=offscreen
+export QT_PLUGIN_PATH="$PROJECT_ROOT/bridge/build/lib/x86_64-linux-gnu/qt6/plugins"
+
+cd "$SCRIPT_DIR"
+
+# Install test dependencies if needed
+python3 -c "import pytest" 2>/dev/null || {
+    echo "pytest not found. Installing..."
+    pip3 install pytest --user
+}
+
+exec python3 -m pytest "$@" .
\ No newline at end of file
diff --git a/tests/test_connection.py b/tests/test_connection.py
new file mode 100644
index 0000000..7020627
--- /dev/null
+++ b/tests/test_connection.py
@@ -0,0 +1,50 @@
+"""Tests for connection management tools."""
+
+import pytest
+
+
+class TestConnection:
+    """Verify connectProbe, probeStatus, disconnectProbe work."""
+
+    def test_tools_listed(self, bridge):
+        tools = bridge.list_tools()
+        names = [t["name"] for t in tools]
+        for expected in ["connectProbe", "connectProbeDefault",
+                         "disconnectProbe", "probeStatus"]:
+            assert expected in names, f"Missing tool: {expected}"
+
+    def test_probe_status_disconnected(self, bridge):
+        status = bridge.call_tool("probeStatus")
+        assert isinstance(status, dict)
+        assert status.get("state") in ("disconnected", "connecting")
+        assert status.get("ready") is False
+
+    def test_connect_and_disconnect(self, connected_bridge):
+        # connectProbeDefault is already called by connected_bridge fixture
+        status = connected_bridge.call_tool("probeStatus")
+        assert isinstance(status, dict)
+        assert status.get("state") == "ready"
+        assert status.get("ready") is True
+        assert "tcp://" in status.get("url", "")
+
+        # Now disconnect
+        result = connected_bridge.call_tool("disconnectProbe")
+        assert isinstance(result, dict)
+        assert result.get("state") == "disconnected"
+
+    def test_reconnect(self, connected_bridge):
+        # Disconnect
+        connected_bridge.call_tool("disconnectProbe")
+
+        # Reconnect with explicit args
+        result = connected_bridge.call_tool("connectProbe",
+                                            {"host": "127.0.0.1", "port": 11732})
+        assert isinstance(result, dict)
+        assert result.get("connected") is True
+        assert result.get("state") == "ready"
+
+    def test_connect_default_after_disconnect(self, connected_bridge):
+        connected_bridge.call_tool("disconnectProbe")
+        result = connected_bridge.call_tool("connectProbeDefault")
+        assert isinstance(result, dict)
+        assert result.get("connected") is True
\ No newline at end of file
diff --git a/tests/test_items.py b/tests/test_items.py
new file mode 100644
index 0000000..1479de5
--- /dev/null
+++ b/tests/test_items.py
@@ -0,0 +1,150 @@
+"""Tests for QML item selection and property inspection."""
+
+import pytest
+import time
+
+
+class TestItemProperties:
+    """Verify selectQuickItem and getItemProperties."""
+
+    @pytest.mark.probe
+    def test_tools_listed(self, bridge):
+        tools = bridge.list_tools()
+        names = [t["name"] for t in tools]
+        for expected in ["selectQuickItem", "getItemProperties"]:
+            assert expected in names
+
+    @pytest.mark.probe
+    def test_select_quick_item(self, connected_bridge):
+        # First get items
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        items = connected_bridge.call_tool("listQuickItems")
+        assert isinstance(items, list) and len(items) > 0, "No items found"
+
+        # Find the first Button-like item
+        def find_buttons(items_list):
+            buttons = []
+            for item in items_list:
+                if "Button" in (item.get("type", "")):
+                    buttons.append(item.get("name", ""))
+                buttons.extend(find_buttons(item.get("children", [])))
+            return buttons
+
+        buttons = find_buttons(items)
+        if not buttons:
+            # Try any item
+            def first_addr(items_list):
+                for item in items_list:
+                    return item.get("name", "")
+            addr = first_addr(items)
+        else:
+            addr = buttons[0]
+
+        result = connected_bridge.call_tool("selectQuickItem", {"address": addr})
+        assert isinstance(result, dict), f"selectQuickItem failed: {result}"
+        assert result.get("propertyCount", 0) > 0, \
+            f"No properties for item {addr}: {result}"
+
+    @pytest.mark.probe
+    def test_get_item_properties(self, connected_bridge):
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        items = connected_bridge.call_tool("listQuickItems")
+
+        def find_any_item(items_list):
+            for item in items_list:
+                addr = item.get("name", "")
+                if addr and not addr.startswith("Loading"):
+                    return addr
+                found = find_any_item(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_any_item(items)
+        if not addr:
+            pytest.skip("No usable item address found")
+
+        props = connected_bridge.call_tool("getItemProperties", {"address": addr})
+        assert isinstance(props, dict), f"getItemProperties failed: {props}"
+        assert "properties" in props, f"No 'properties' key: {list(props.keys())}"
+
+    @pytest.mark.probe
+    def test_item_has_position(self, connected_bridge):
+        """Verify that a Button item has x, y, width, height properties."""
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        items = connected_bridge.call_tool("listQuickItems")
+
+        # Find a Button_QMLTYPE item
+        def find_button(items_list):
+            for item in items_list:
+                if "Button" in (item.get("type", "")):
+                    return item.get("name", "")
+                found = find_button(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_button(items)
+        if not addr:
+            pytest.skip("No Button item found")
+
+        props = connected_bridge.call_tool("getItemProperties", {"address": addr})
+        simple = props.get("properties", {})
+        for key in ("x", "y", "width", "height"):
+            assert key in simple, f"Button missing '{key}' property"
+            val = simple[key].get("value", "")
+            assert val != "", f"Button.{key} is empty"
+
+    @pytest.mark.probe
+    def test_item_has_visual_properties(self, connected_bridge):
+        """Verify items have opacity, visible, z, rotation, scale."""
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        items = connected_bridge.call_tool("listQuickItems")
+
+        def find_addr(items_list):
+            for item in items_list:
+                addr = item.get("name", "")
+                if addr and not addr.startswith("Loading") and addr != "ApplicationWindow":
+                    return addr
+                found = find_addr(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_addr(items)
+        if not addr:
+            pytest.skip("No suitable item found")
+
+        props = connected_bridge.call_tool("getItemProperties", {"address": addr})
+        simple = props.get("properties", {})
+        for key in ("opacity", "visible", "z"):
+            assert key in simple, f"Item missing '{key}'"
+
+    @pytest.mark.probe
+    def test_property_model_has_groups(self, connected_bridge):
+        """Verify items have nested property groups (background, contentItem, etc.)."""
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        items = connected_bridge.call_tool("listQuickItems")
+
+        def find_button(items_list):
+            for item in items_list:
+                if "Button" in (item.get("type", "")):
+                    return item.get("name", "")
+                found = find_button(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_button(items)
+        if not addr:
+            pytest.skip("No Button item found")
+
+        props = connected_bridge.call_tool("getItemProperties", {"address": addr})
+        groups = props.get("groups", {})
+        # Buttons typically have [background], [contentItem], [parent], [window]
+        assert len(groups) > 0, f"No property groups found: {list(props.keys())}"
\ No newline at end of file
diff --git a/tests/test_navigation.py b/tests/test_navigation.py
new file mode 100644
index 0000000..0e691a7
--- /dev/null
+++ b/tests/test_navigation.py
@@ -0,0 +1,93 @@
+"""Tests for navigation tools (windows, items, scene graph tree)."""
+
+import pytest
+
+
+class TestNavigation:
+    """Verify listQuickWindows, selectQuickWindow, listQuickItems, listScenegraphNodes."""
+
+    def test_tools_listed(self, bridge):
+        tools = bridge.list_tools()
+        names = [t["name"] for t in tools]
+        for expected in ["listQuickWindows", "selectQuickWindow",
+                         "listQuickItems", "listScenegraphNodes"]:
+            assert expected in names
+
+    @pytest.mark.probe
+    def test_list_windows(self, connected_bridge):
+        windows = connected_bridge.call_tool("listQuickWindows")
+        assert isinstance(windows, list)
+        assert len(windows) >= 1
+        for w in windows:
+            assert "address" in w
+            assert "type" in w
+
+    @pytest.mark.probe
+    def test_select_window(self, connected_bridge):
+        result = connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        assert isinstance(result, dict)
+        assert result.get("status") == "selected"
+
+    @pytest.mark.probe
+    def test_list_items(self, connected_bridge):
+        # Select window first so item model populates
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        import time
+        time.sleep(1)
+        items = connected_bridge.call_tool("listQuickItems")
+        assert isinstance(items, list)
+        # May be empty if model hasn't populated yet; that's OK
+        if items:
+            assert isinstance(items[0], dict)
+            assert "type" in items[0]
+
+    @pytest.mark.probe
+    def test_list_items_with_window_count(self, connected_bridge):
+        """Collect all items and verify at least some are found."""
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        import time
+        time.sleep(1)
+        items = connected_bridge.call_tool("listQuickItems")
+
+        def count_all(items_list):
+            count = 0
+            for item in items_list:
+                count += 1
+                count += count_all(item.get("children", []))
+            return count
+
+        if items:
+            total = count_all(items)
+            assert total > 0
+
+    @pytest.mark.probe
+    def test_list_scenegraph_nodes(self, connected_bridge):
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        import time
+        time.sleep(1)
+
+        nodes = connected_bridge.call_tool("listScenegraphNodes")
+        assert isinstance(nodes, list)
+        if nodes:
+            assert isinstance(nodes[0], dict)
+            # Root should be "Root Node"
+            assert nodes[0].get("type") == "Root Node"
+
+    @pytest.mark.probe
+    def test_scenegraph_has_geometry_nodes(self, connected_bridge):
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        import time
+        time.sleep(1)
+        nodes = connected_bridge.call_tool("listScenegraphNodes")
+
+        def find_geometry(items_list):
+            for item in items_list:
+                if item.get("type") == "Geometry Node":
+                    return item
+                found = find_geometry(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        geo = find_geometry(nodes)
+        assert geo is not None, "No Geometry Node found in SG tree"
\ No newline at end of file
diff --git a/tests/test_scenegraph.py b/tests/test_scenegraph.py
new file mode 100644
index 0000000..77dd24c
--- /dev/null
+++ b/tests/test_scenegraph.py
@@ -0,0 +1,157 @@
+"""Tests for SceneGraph node selection and geometry/material tools."""
+
+import pytest
+import time
+
+
+class TestSceneGraph:
+    """Verify selectScenegraphNode, getNodeVertices, getNodeAdjacency, etc."""
+
+    @pytest.mark.probe
+    def test_tools_listed(self, bridge):
+        tools = bridge.list_tools()
+        names = [t["name"] for t in tools]
+        for expected in [
+            "selectScenegraphNode", "getNodeVertices", "getNodeAdjacency",
+            "getMaterialShaders", "getShaderSource", "getMaterialProperties",
+            "setRenderMode", "setSlowMode",
+        ]:
+            assert expected in names, f"Missing tool: {expected}"
+
+    @pytest.mark.probe
+    def test_select_scenegraph_node(self, connected_bridge):
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        nodes = connected_bridge.call_tool("listScenegraphNodes")
+
+        # Find first Geometry Node
+        def find_geo(items_list):
+            for item in items_list:
+                if item.get("type") == "Geometry Node":
+                    return item.get("address", "")
+                found = find_geo(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_geo(nodes)
+        if not addr:
+            pytest.skip("No Geometry Node found")
+
+        result = connected_bridge.call_tool("selectScenegraphNode", {"address": addr})
+        assert isinstance(result, dict), f"selectScenegraphNode failed: {result}"
+        assert result.get("type") == "Geometry Node"
+        assert "hasGeometry" in result
+        assert "hasMaterial" in result
+
+    @pytest.mark.probe
+    def test_get_node_vertices(self, connected_bridge):
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        nodes = connected_bridge.call_tool("listScenegraphNodes")
+
+        def find_geo(items_list):
+            for item in items_list:
+                if item.get("type") == "Geometry Node":
+                    return item.get("address", "")
+                found = find_geo(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_geo(nodes)
+        if not addr:
+            pytest.skip("No Geometry Node found")
+
+        result = connected_bridge.call_tool("getNodeVertices", {"address": addr})
+        assert isinstance(result, dict)
+        # May return "no vertex data" for software renderer -- that's OK
+        assert "error" in result or "vertexCount" in result
+
+    @pytest.mark.probe
+    def test_get_node_adjacency(self, connected_bridge):
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        nodes = connected_bridge.call_tool("listScenegraphNodes")
+
+        def find_geo(items_list):
+            for item in items_list:
+                if item.get("type") == "Geometry Node":
+                    return item.get("address", "")
+                found = find_geo(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_geo(nodes)
+        if not addr:
+            pytest.skip("No Geometry Node found")
+
+        result = connected_bridge.call_tool("getNodeAdjacency", {"address": addr})
+        assert isinstance(result, dict)
+        assert "error" in result or "drawingMode" in result
+
+    @pytest.mark.probe
+    def test_get_material_shaders(self, connected_bridge):
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        nodes = connected_bridge.call_tool("listScenegraphNodes")
+
+        def find_geo(items_list):
+            for item in items_list:
+                if item.get("type") == "Geometry Node":
+                    return item.get("address", "")
+                found = find_geo(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_geo(nodes)
+        if not addr:
+            pytest.skip("No Geometry Node found")
+
+        result = connected_bridge.call_tool("getMaterialShaders", {"address": addr})
+        assert isinstance(result, dict)
+        # Software renderer -> no shaders; that's expected
+        assert "error" in result or isinstance(result, list)
+
+    @pytest.mark.probe
+    def test_get_material_properties(self, connected_bridge):
+        connected_bridge.call_tool("selectQuickWindow", {"index": 0})
+        time.sleep(1)
+        nodes = connected_bridge.call_tool("listScenegraphNodes")
+
+        def find_geo(items_list):
+            for item in items_list:
+                if item.get("type") == "Geometry Node":
+                    return item.get("address", "")
+                found = find_geo(item.get("children", []))
+                if found:
+                    return found
+            return None
+
+        addr = find_geo(nodes)
+        if not addr:
+            pytest.skip("No Geometry Node found")
+
+        result = connected_bridge.call_tool("getMaterialProperties", {"address": addr})
+        assert isinstance(result, dict)
+        assert "error" in result or "properties" in result
+
+    @pytest.mark.probe
+    def test_set_render_mode(self, connected_bridge):
+        result = connected_bridge.call_tool("setRenderMode",
+                                            {"mode": "VisualizeOverdraw"})
+        assert isinstance(result, dict)
+        assert result.get("renderMode") == "VisualizeOverdraw"
+
+        # Reset
+        connected_bridge.call_tool("setRenderMode", {"mode": "NormalRendering"})
+
+    @pytest.mark.probe
+    def test_set_slow_mode(self, connected_bridge):
+        result = connected_bridge.call_tool("setSlowMode", {"enabled": True})
+        assert isinstance(result, dict)
+        assert result.get("slowMode") is True
+
+        connected_bridge.call_tool("setSlowMode", {"enabled": False})
\ No newline at end of file