filesystem-mcp-env-guard
A path-level protection project for filesystem MCP servers written in Rust, designed to prevent agents from reading sensitive files such as .env through the filesystem MCP. It performs parameter checks and response modifications before and after the execution of tools/call requests via the ExtMCP gRPC service.
Timeline (last 90 days)
The policy server's deny list includes: .env, .ssh, .git/, credentials, id_rsa, id_ed25519, .aws/, .npmrc, .netrc.
A post in the r/mcp community describes this failure mode: Claude nearly read a production .env through the filesystem MCP, the poster eventually wrote a set of protections in Rust, and the author built the filesystem-mcp-env-guard project for this purpose.
All Facts (2)
The policy server's deny list includes: .env, .ssh, .git/, credentials, id_rsa, id_ed25519, .aws/, .npmrc, .netrc.
50%UnverifiedA post in the r/mcp community describes this failure mode: Claude nearly read a production .env through the filesystem MCP, the poster eventually wrote a set of protections in Rust, and the author built the filesystem-mcp-env-guard project for this purpose.
50%