The anthropic-toolkit npm package is a typosquatting malicious package that does not provide legitimate library code but instead executes a post-install script that collects extensive sensitive information from the host system. This includes host and user identifiers, git configuration and history, SSH public key emails, cloud account details, internal DNS domains, and CI environment metadata. The collected data is sent to a remote server, enabling high-value reconnaissance for targeted phishing and supply-chain attacks. Installation of this package compromises the host, and all secrets and keys on the affected system should be rotated from a separate, trusted machine.