MCP Defender – OSS AI Firewall for Protecting MCP in Cursor/Claude etc

Show HN: MCP Defender – OSS AI Firewall for Protecting MCP in Cursor/Claude etc

MCP Defender – OSS AI Firewall for Protecting MCP in Cursor/Claude etc operates in show hn launch.

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Hi HN,MCP Defender is an open source desktop app that automatically proxies your MCP traffic in AI apps like Cursor, Claude, Windsurf and VSCode. It then scans all requests and responses between the apps and the MCP tools they call. If it detects anything malicious, it alerts you and lets you allow or block the tool call.While the threat landscape of MCP is still being actively researched, there are dangerous things that MCP Defender can block today. For example, a developer asks Cursor to fix a Github issue with an attached crash log. However, the Github issue was created by an attacker who included secret instructions buried in the crash log. These instructions tell Cursor to send the deve

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Website: mcpdefender.com