diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..bd3ad87
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,60 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project overview
+
+`qtm_rt` is the Qualisys SDK for Python — a client library that implements Qualisys' RealTime (RT) protocol for talking to QTM (Qualisys Track Manager). Published to PyPI as `qtm-rt`. Targets Python 3.10+ and RT protocol version 1.8+. Little-endian only; default port 22223.
+
+## Common commands
+
+```bash
+# Setup
+python -m venv .venv
+source ./.venv/Scripts/activate   # Windows bash; on PowerShell: .\.venv\Scripts\Activate.ps1
+pip install -r requirements-dev.txt
+
+# Tests
+pytest test/
+pytest test/qrtconnection_test.py::test_connect_no_loop   # single test
+
+# Lint
+python -m ruff check .
+
+# Build sdist + wheel into dist/
+python -m build
+
+# Build Sphinx docs into docs/_build/html/
+make -C docs html
+
+# Enable debug logging at runtime
+QTM_LOGGING=debug python your_script.py
+```
+
+Release flow — bump `version` in `pyproject.toml` (and `docs/conf.py`), open a PR, merge to master, then create a GitHub Release on the tag `vX.Y.Z`. Publishing the release fires `.github/workflows/release.yml`, which lints with Ruff, runs tests, builds the sdist+wheel, twine-checks, uploads to PyPI via Trusted Publishing, and attaches `qtm-rt-examples.zip` (the `examples/` directory plus `Demo.qtm`) to the release. Docs are still a manual step: build with `make -C docs html`, copy `docs/_build/html/*` into the sibling `../qualisys_python_sdk_gh_pages` checkout **preserving the legacy `v102/`, `v103/`, `v212/` directories**, commit/push that branch.
+
+## Architecture
+
+Everything is `asyncio`-based and built around `qtm_rt.connect()` → returns a `QRTConnection`. The data flow:
+
+- **`qrt.py`** — public API surface. `connect()` opens a TCP connection wrapped in `QTMProtocol`, negotiates the RT protocol version (default `"1.25"`), and returns a `QRTConnection` exposing async methods for every RT command (`stream_frames`, `get_current_frame`, `get_parameters`, `take_control`, `start`, `stop`, `load`, `save`, `calibrate`, etc.). The `@validate_response([...])` decorator asserts the server's reply starts with an expected prefix and raises `QRTCommandException` otherwise. `QRTConnection` is an async context manager — prefer `async with await qtm_rt.connect(...) as c:` so the transport is closed deterministically on scope exit.
+- **`protocol.py`** — `QTMProtocol` is an `asyncio.Protocol` subclass. Outgoing commands are framed with `RTheader` (`<II`: size + packet type) and one of the `QRTPacketType` variants. Responses are dispatched through a `_handlers` dict keyed on packet type. Single-shot command replies are delivered via a `request_queue` of futures (FIFO via `popleft`, with done-future skipping so a late response to a cancelled caller doesn't crash the transport); streaming data goes to the user-supplied `on_packet` callback instead. The first `streamframes` response is synthesized as `b"Ok"` so callers can await the command even though real data packets arrive on the streaming path.
+- **`receiver.py`** — buffers raw bytes, slices them into complete packets using the header size field, converts the type byte to `QRTPacketType`, wraps data/event payloads into `QRTPacket`/`QRTEvent`, and routes to the handler.
+- **`packet.py`** — all binary layouts. Uses `struct.Struct` and `namedtuple` for every RT component type (2D/3D/6D/Analog/Force/GazeVector/EyeTracker/Image/Skeleton/Timecode/etc.). `QRTPacket` exposes `get_*` accessors that lazily parse components on demand. `QRTPacketType` and `QRTEvent` are enums matching the protocol byte values.
+- **`discovery.py`** — UDP broadcast discovery of QTM instances on the LAN (`Discover`). Tracks the datagram transport and closes it on iteration end so the socket doesn't leak.
+- **`control.py`** — `TakeControl`, an async context manager wrapping `take_control`/`release_control`.
+- **`reboot.py`** — utility to reboot cameras.
+
+Key invariants when modifying:
+
+- Component and parameter names accepted by `stream_frames` / `get_current_frame` / `get_parameters` are validated against hardcoded allow-lists in `qrt.py` (`_validate_components` and the inline list in `get_parameters`). Adding a new RT component requires updating **both** that list and `packet.py`.
+- `request_queue` is FIFO (`popleft`). When a caller's `asyncio.wait_for` cancels the queued future, the next QTM response is dropped rather than delivered to it — keep this property when adding code paths that enqueue futures.
+- `on_packet` callbacks are sync; they run inside the asyncio event loop, so blocking work there will stall the protocol.
+
+## Testing notes
+
+Tests use `pytest`, `pytest-asyncio` (markers required: `@pytest.mark.asyncio`), and `pytest-mock`. They exercise `connect()` and `QRTConnection` by mocking `loop.create_connection` — there is no live QTM in CI. The Python-version matrix (3.10–3.14) runs on every PR via `.github/workflows/ci.yml`. New protocol commands should get analogous mocked tests in `test/qrtconnection_test.py` or `test/qtmprotocol_test.py`.
+
+## Known gaps (from README)
+
+`GetCaptureC3D`, `GetCaptureQTM`, and per-channel analog selection are intentionally not implemented.
diff --git a/qtm_rt/discovery.py b/qtm_rt/discovery.py
index 7c9efa4..cad4ef3 100644
--- a/qtm_rt/discovery.py
+++ b/qtm_rt/discovery.py
@@ -66,6 +66,7 @@ def __init__(self, ip_address):
         self.ip_address = ip_address
         self.queue = asyncio.Queue()
         self.first = True
+        self._transport = None
 
     def __aiter__(self):
         return self
@@ -78,7 +79,7 @@ async def __anext__(self) -> QRTDiscoveryResponse:
             def protocol_factory():
                 return QRTDiscoveryProtocol(receiver=self.queue.put_nowait)
 
-            _, protocol = await loop.create_datagram_endpoint(
+            self._transport, protocol = await loop.create_datagram_endpoint(
                 protocol_factory,
                 local_addr=(self.ip_address, 0),
                 allow_broadcast=True,
@@ -92,10 +93,16 @@ def protocol_factory():
         result = await self.queue.get()
         if result is None:
             LOG.debug("Discovery timed out")
+            self._close()
             raise StopAsyncIteration
 
         LOG.debug(result)
         call_handle.cancel()
         return result
 
+    def _close(self):
+        if self._transport is not None:
+            self._transport.close()
+            self._transport = None
+
 
diff --git a/qtm_rt/qrt.py b/qtm_rt/qrt.py
index 2e0f449..ff60a1c 100644
--- a/qtm_rt/qrt.py
+++ b/qtm_rt/qrt.py
@@ -45,9 +45,16 @@ def __init__(self, protocol: QTMProtocol, timeout):
         self._protocol = protocol
         self._timeout = timeout
 
+    async def __aenter__(self):
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb):
+        self.disconnect()
+
     def disconnect(self):
-        """Disconnect from QTM."""
-        self._protocol.transport.close()
+        """Disconnect from QTM. Safe to call multiple times."""
+        if self._protocol.transport is not None:
+            self._protocol.transport.close()
 
     def has_transport(self):
         """ Check if connected to QTM """