diff --git a/rust/flake.nix b/rust/flake.nix
index 7daacf2..40b9b6b 100644
--- a/rust/flake.nix
+++ b/rust/flake.nix
@@ -18,7 +18,10 @@
         pkgs = import nixpkgs { inherit system; };
         fx = fenix.packages.${system};
         rust = fx.combine [
-          fx.stable.toolchain
+          (fx.fromToolchainFile {
+            file = ./rox/rust-toolchain.toml;
+            sha256 = "sha256-AJ6LX/Q/Er9kS15bn9iflkUwcgYqRQxiOIL2ToVAXaU=";
+          })
         ];
         buildInputs = [
           rust
diff --git a/rust/rox/rust-toolchain.toml b/rust/rox/rust-toolchain.toml
new file mode 100644
index 0000000..971210b
--- /dev/null
+++ b/rust/rox/rust-toolchain.toml
@@ -0,0 +1,4 @@
+[toolchain]
+channel = "1.85.0"
+components = ["rust-src", "rustc", "cargo", "rust-std", "rustfmt", "clippy", "rust-analyzer"]
+profile = "minimal"