diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..038e186
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,200 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+**instrumentserver** is a client-server framework for managing QCoDeS instruments in a networked environment. It enables remote control of lab instruments through proxy objects, allowing multiple clients to interact with instruments running on a central server. The server manages a QCoDeS Station and exposes instruments/parameters via ZMQ messaging.
+
+## Installation
+
+```bash
+# Developer install (no dependencies)
+pip install --no-deps -e /path/to/instrumentserver/
+
+# With dependencies
+pip install -e /path/to/instrumentserver/
+```
+
+## Console Scripts
+
+The package installs four console scripts:
+
+```bash
+# Start server with GUI (default)
+instrumentserver -p 5555
+
+# Start server without GUI
+instrumentserver -p 5555 --gui False
+
+# Start with config file
+instrumentserver -c /path/to/config.yaml
+
+# Start detached server
+instrumentserver-detached
+
+# Start parameter manager GUI
+instrumentserver-param-manager --name parameter_manager --port 5555
+
+# Start monitoring listener
+instrumentserver-listener
+```
+
+### Server Arguments
+- `-p/--port` - Port number (default: 5555)
+- `--gui` - Enable/disable GUI (default: True)
+- `--allow_user_shutdown` - Allow users to shutdown server
+- `-a/--listen_at` - Network addresses to listen on
+- `-i/--init_script` - Initialization script path
+- `-c/--config` - YAML config file path
+
+## Testing
+
+```bash
+# Run all tests
+pytest
+
+# Run specific test
+pytest test/pytest/test_basic_functionality.py
+pytest test/pytest/test_serialize.py
+
+# Run with verbose output
+pytest -v
+```
+
+Tests are in `test/pytest/` with fixtures defined in `test/pytest/conftest.py`.
+
+## Core Architecture
+
+### Client-Server Communication
+
+The architecture uses **ZMQ (ZeroMQ)** with a REQ-REP pattern for client-server communication plus PUB-SUB for broadcasting parameter updates.
+
+**Server Side:**
+- **StationServer** ([instrumentserver/server/core.py](instrumentserver/server/core.py)) - Main server managing a QCoDeS Station
+  - Listens on port N (e.g., 5555) for requests via ZMQ ROUTER socket
+  - Broadcasts on port N+1 (e.g., 5556) via ZMQ PUB socket for parameter updates
+  - Runs in a QThread with Qt signals for GUI integration
+  - Handles concurrent requests via ThreadPoolExecutor
+
+**Client Side:**
+- **BaseClient** ([instrumentserver/client/core.py](instrumentserver/client/core.py)) - Low-level ZMQ client
+  - Uses DEALER socket for async request/reply
+  - Handles timeouts and reconnection
+  - Configurable exception raising
+- **Client** ([instrumentserver/client/proxy.py](instrumentserver/client/proxy.py)) - High-level client that creates proxy objects
+
+### Blueprint System
+
+The **blueprints** module ([instrumentserver/blueprints.py](instrumentserver/blueprints.py)) defines all objects exchanged between client and server. This is the communication contract.
+
+**Key Blueprint Types:**
+- `ParameterBluePrint` - Describes a parameter (name, path, gettable/settable, unit)
+- `InstrumentModuleBluePrint` - Describes an instrument/channel (parameters, methods, submodules)
+- `MethodBluePrint` - Describes a callable method
+- `ParameterBroadcastBluePrint` - Parameter update broadcasts
+
+**Message Types:**
+- `ServerInstruction` - Client requests (operations: get_blueprint, call, get, set, create_instrument, etc.)
+- `ServerResponse` - Server responses (message, error)
+- `CallSpec` - Function call specification (target, args, kwargs)
+- `InstrumentCreationSpec` - Instrument instantiation spec
+
+**Serialization:**
+All blueprints implement `toJson()` for serialization. The module handles nested objects, numpy arrays, and custom classes via introspection. Use `deserialize_obj()` to reconstruct objects from JSON.
+
+### Proxy Objects
+
+Clients interact with instruments through **proxy objects** that mirror the server-side structure:
+
+- **ProxyInstrument** - Mirrors QCoDeS Instrument
+- **ProxyParameter** - Mirrors QCoDeS Parameter
+  - `get()` sends ServerInstruction with Operation.get
+  - `set(value)` sends ServerInstruction with Operation.set
+- **ProxyMethod** - Mirrors instrument methods
+
+All inherit from **ProxyMixin** which provides:
+- `askServer()` - Send requests via client or direct sendRequest
+- Blueprint-based initialization
+- Remote path tracking
+
+Pattern:
+```python
+cli = Client(host='localhost', port=5555)
+instrument = cli.find_or_create_instrument('my_instrument')
+param = instrument.some_parameter
+value = param()  # Sends get request to server
+param(new_value)  # Sends set request to server
+```
+
+### Parameter Manager
+
+**ParameterManager** ([instrumentserver/params.py](instrumentserver/params.py)) is a virtual QCoDeS instrument for managing arbitrary parameters without physical instruments:
+
+- Stores parameters in JSON "profiles" (e.g., `parameter_manager-qubit1.json`)
+- Allows dynamic parameter addition/removal
+- Supports nested parameter groups
+- Used for experiment configuration and calibration values
+
+### Serialization System
+
+**serialize.py** ([instrumentserver/serialize.py](instrumentserver/serialize.py)) provides JSON serialization for instrument states:
+
+**Key Functions:**
+- `toParamDict(station/instrument)` - Extract parameter values to dict
+- `fromParamDict(paramDict, station/instrument)` - Load parameter values from dict
+
+**Format:**
+```python
+{
+    "instrument.parameter": {
+        "value": 123,
+        "unit": "mV"
+    }
+}
+# or simplified:
+{
+    "instrument.parameter": 123
+}
+```
+
+Parameter addressing matches QCoDeS station paths: `station.instrument.submodule.parameter`.
+
+## Module Organization
+
+- **instrumentserver/server/** - Server implementation
+  - `core.py` - StationServer, request handling
+  - `application.py` - GUI application wrapper
+  - `pollingWorker.py` - Background parameter polling
+- **instrumentserver/client/** - Client implementation
+  - `core.py` - BaseClient, low-level communication
+  - `proxy.py` - Client class, proxy objects
+- **instrumentserver/gui/** - Qt GUI components
+  - `instruments.py` - Instrument control widgets
+  - `parameters.py` - Parameter editing widgets
+- **instrumentserver/** - Core utilities
+  - `blueprints.py` - Communication protocol definitions
+  - `params.py` - ParameterManager
+  - `serialize.py` - Instrument state serialization
+  - `helpers.py` - Utility functions (nestedAttributeFromString, etc.)
+  - `base.py` - ZMQ send/recv helpers
+  - `config.py` - YAML config loading
+  - `apps.py` - Console script entry points
+- **instrumentserver/monitoring/** - Monitoring tools
+  - `listener.py` - Broadcast listener for monitoring
+- **instrumentserver/testing/** - Test utilities and dummy instruments
+- **instrumentserver/deployment/** - Grafana dashboard for instrument monitoring (Docker setup)
+
+## Key Patterns
+
+### Nested Attribute Access
+Use `nestedAttributeFromString(obj, "sub.module.param")` to access nested attributes from dot-notation strings.
+
+### Operations Enum
+All server operations are defined in `Operation` enum (blueprints.py): `get_blueprint`, `call`, `get`, `set`, `create_instrument`, `list_instruments`, etc.
+
+### Thread Safety
+Server uses Qt threading model - StationServer runs in separate QThread, parameter access happens via thread pool to avoid blocking the message loop.
+
+### Broadcasting
+Parameter sets trigger broadcasts on port+1, clients can subscribe to monitor parameter changes in real-time without polling.
diff --git a/instrumentserver/gui/instruments.py b/instrumentserver/gui/instruments.py
index 0d5ccf3..87b00d8 100644
--- a/instrumentserver/gui/instruments.py
+++ b/instrumentserver/gui/instruments.py
@@ -304,7 +304,11 @@ def updateParameter(self, bp: ParameterBroadcastBluePrint):
             item = self.findItems(fullName, QtCore.Qt.MatchExactly | QtCore.Qt.MatchRecursive, 0)
             if len(item) == 0:
                 if fullName not in self.itemsHide:
-                    self.addItem(fullName, element=nestedAttributeFromString(self.instrument, fullName))
+                    try:
+                        self.addItem(fullName, element=nestedAttributeFromString(self.instrument, fullName))
+                    except AttributeError:
+                        # Parameter/submodule no longer exists (likely due to profile switch)
+                        logger.debug(f"Ignoring broadcast for non-existent parameter: {fullName}")
             else:
                 assert isinstance(item[0], ItemBase)
                 # The model can't actually modify the widget since it knows nothing about the view itself.
@@ -457,7 +461,7 @@ def refresh(self):
         self.clear()
         for profile in self.params.list_profiles():
             self.addItem(self.params.cleanProfileName(profile))
-            if profile == currentlySelected:
+            if self.params.cleanProfileName(profile) == currentlySelected:
                 self.setCurrentIndex(self.count() - 1)
         self.refreshing = False