Claude almost read his production .env, so he built a 1MB Rust MCP guardrail
Significant_Yak2566 · reddit · 2026-10-05
A developer found Claude Desktop, via the official filesystem MCP server, attempting to read his root .env containing live API credentials and database strings. He argues the Allow/Deny modal fails in practice: "Always allow" is muscle memory, permissions are all-or-nothing, and hallucinated relative paths are happily served. He open-sourced Argos, a 1MB Rust binary acting as a transparent deterministic policy checker between Claude and any MCP server — no Python, no Docker, no telemetry. Repo: github.com/JUSICK/Argos-mcp-guardrail.
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