Fable 5 Unleashes Agents in Your Editor—Opening New Security Vulnerabilities

Anthropic's Fable 5 brings autonomous, multi-agent capabilities to VS Code, empowering extensions to read files, execute commands, and access external APIs with minimal human oversight. This shift introduces new attack vectors—particularly tool poisoning, where hidden malicious instructions can lurk in tool descriptions. With 43% of public MCP servers already containing vulnerabilities, the burden of AI security now falls largely on developers rather than platform gatekeepers.