MCP Security KitMCP config security checker
Paste the MCP config from Claude Desktop, Cursor, VS Code or Windsurf. In a second you'll see hard-coded secrets, unpinned packages, over-broad file access, unencrypted remote servers and risky container settings, with a fix for each.
Nothing leaves your browser. The check runs on this page, and the page is blocked from making network requests, so your config is never uploaded.
Where to find it: Claude Desktop claude_desktop_config.json · Cursor ~/.cursor/mcp.json · VS Code .vscode/mcp.json · Windsurf ~/.codeium/windsurf/mcp_config.json
Checking the file is step one
These checks read how servers are configured. They can't see what a server does once it's running. Agent Trust Cloud keeps a registry of MCP servers and their tools, classifies each tool's risk, and decides at runtime whether an agent's tool call is allowed, denied or sent for approval.
Start free with Discover How MCP security works in Agent Trust Cloud
What this checks
- Secrets written into the file — API keys, tokens and passwords in
env, headers, arguments or URLs. Values are shown partly hidden. - Unpinned packages and images —
npx,uvxanddockerservers that fetch whatever version is newest on every start. - Broad file access — filesystem servers given
/, your home folder or a whole drive. - Unencrypted remote servers —
http://endpoints that aren't on your own machine. - Container settings —
--privileged, host networking, the Docker socket and broad host mounts. - Command execution — servers launched through a shell or built to run shell commands, and tools set to run without asking.
What it can't check
It doesn't connect to your servers, so it can't see tool descriptions that carry hidden instructions, tools that change after you approved them, or what data a server actually reads. Those need controls where the agent runs. The MCP server security guide covers the full threat model and a pre-install checklist.
Questions
Is my config sent anywhere?
No. The page is served as plain files and its security policy blocks all outgoing requests (connect-src 'none'). You can disconnect from the internet after the page loads and it still works.
Which clients does it understand?
Configs with an mcpServers block (Claude Desktop, Cursor, Windsurf and most others) and VS Code's servers block, including its comments and trailing commas.
Is a clean result a guarantee?
No. These are pattern checks on the file, a quick first pass rather than a full review.