ToolTrust Scanner is a free static security scanner designed for MCP tool definitions, offering a robust solution for assessing the trustworthiness of tools before use. It operates as an MCP server, CLI, or CI tool, evaluating each tool's risk and assigning a trust grade from A to F, which indicates the level of security and potential vulnerabilities associated with that tool. This feature is crucial for developers and organizations looking to mitigate risks related to prompt injections, data exfiltration, and other security threats.

The scanner utilizes a series of predefined static analysis rules to inspect tool definitions, identifying critical issues such as tool poisoning and privilege escalation. It connects to live MCP servers or reads local configurations to perform comprehensive scans in seconds, ensuring that security assessments are both efficient and thorough. ToolTrust aims to enhance the security of MCP workflows by providing real-time risk assessments and actionable insights.