dsh-prompt-antivirus: DeepSeek Harness Global Prompt Injection Prevention Plugin

`dsh-prompt-antivirus` is a global prompt-injection prevention plugin for LLM agents, designed to defend against "context virus" infections. It scans across four key points—tool parameters, tool results, model messages, and output streams—and offers three defense modes: isolation, blocking, and monitoring, with isolation as the default. Its core advantage is a disk-based signature library that supports hot updates, enabling the learning of attack samples via commands and the export/import of rules. Implemented entirely in JS with no native dependencies, the plugin is mounted at the profile layer and applies globally to presets and subagents, effectively mitigating known attacks through least-privilege and human-approval policies.