The @agent-link/agent npm package contains malicious code that connects to a hardcoded WebSocket relay at wss://msclaude.ai. This relay can send commands that are executed interactively on the host system via a locally spawned shell, enabling remote command execution. The package also fetches and installs updates from the same unverified origin, allowing an attacker controlling the relay to replace the package with malicious versions. The publisher identity and origin of the relay are unclear and unverified, increasing the risk of supply chain compromise. Multiple specific versions of the package are affected.