flake.lock

@@ -18,7 +18,24 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-nixpkgs": "rust-nixpkgs"
+      }
+    },
+    "rust-nixpkgs": {
+      "locked": {
+        "lastModified": 1786599213,
+        "narHash": "sha256-yNJd40f11EzXBjSByCB7IPpeFFAdeoSKKM67dGkfFoU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "0e251e24a4f24e036a084b6b4b2d2491af4167f4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "0e251e24a4f24e036a084b6b4b2d2491af4167f4",
+        "type": "github"
       }
     }
   },

flake.nix

@@ -12,10 +12,14 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    # Newer nixpkgs for yarr: the pinned nixpkgs has rustc 1.95 but yarr
+    # needs 1.97.1. Bumping the main nixpkgs input breaks aioimaplib
+    # (email server dep), so use a separate input just for yarr's rust.
+    rust-nixpkgs.url = "github:NixOS/nixpkgs/0e251e24a4f24e036a084b6b4b2d2491af4167f4";
   };
 
   outputs =
-    { self, nixpkgs, ... }:
+    { self, nixpkgs, rust-nixpkgs, ... }:
     let
       supportedSystems = [
         "x86_64-linux"
@@ -36,7 +40,10 @@
             inherit system;
             overlays = [ self.overlays.default ];
           };
-          mcpPackages = import ./packages { inherit pkgs; };
+          # yarr needs rustc 1.97.1; the main nixpkgs input only has 1.95.
+          # Build its rust toolchain from the newer rust-nixpkgs input.
+          rustPkgs = import rust-nixpkgs { inherit system; };
+          mcpPackages = import ./packages { inherit pkgs rustPkgs; };
         in
         mcpPackages // {
           default = pkgs.symlinkJoin {
@@ -53,7 +60,8 @@
             inherit system;
             overlays = [ self.overlays.default ];
           };
-          mcpPackages = import ./packages { inherit pkgs; };
+          rustPkgs = import rust-nixpkgs { inherit system; };
+          mcpPackages = import ./packages { inherit pkgs rustPkgs; };
         in
         {
           default = pkgs.mkShell {

overlays/default.nix

@@ -16,8 +16,11 @@
 #     };
 #   }
 #
+# Note: yarr is excluded from the overlay because it needs rustc 1.97.1
+# from a specific nixpkgs input. Build it via nix build .#yarr on the
+# flake directly.
 final: prev:
 let
   mcpPackages = import ../packages { pkgs = final; };
 in
-mcpPackages
+builtins.removeAttrs mcpPackages [ "yarr" ]

packages/default.nix

@@ -1,4 +1,4 @@
-{ pkgs }:
+{ pkgs, rustPkgs ? pkgs }:
 
 {
   manim-mcp-server = pkgs.callPackage ./manim-mcp-server/package.nix { };
@@ -28,5 +28,6 @@
   navidrome-mcp = pkgs.callPackage ./navidrome-mcp/package.nix { };
   ovhcloud-mcp = pkgs.callPackage ./ovhcloud-mcp/package.nix { };
   slskd-mcp = pkgs.callPackage ./slskd-mcp/package.nix { };
+  yarr = rustPkgs.callPackage ./yarr/package.nix { };
   # example-mcp-server = pkgs.callPackage ./example-mcp-server/package.nix { };
-}
+}

packages/yarr/package.nix

@@ -0,0 +1,31 @@
+{
+  lib,
+  rustPlatform,
+  fetchFromGitHub,
+}:
+
+rustPlatform.buildRustPackage rec {
+  pname = "yarr";
+  version = "2.2.2";
+
+  src = fetchFromGitHub {
+    owner = "dinglebear-ai";
+    repo = "yarr";
+    rev = "15a599bab38a";
+    hash = "sha256-PlD2NYK06rVdKirUq2dw04WL9yFrM2TB1d67Weero0k=";
+  };
+
+  cargoHash = "sha256-e89uYPLqwhh1epedUvVEDTT4y35nuwLWlco4AVvKoK4=";
+
+  # The cargo test phase hangs (0% CPU, no rustc procs) — likely a test
+  # blocking on network. Skip tests; we only need the binary.
+  doCheck = false;
+
+  meta = with lib; {
+    description = "Rust MCP server for media automation fleets - Sonarr, Radarr, Prowlarr, Jellyfin, SABnzbd, qBittorrent, Plex";
+    homepage = "https://github.com/dinglebear-ai/yarr";
+    license = licenses.agpl3Only;
+    mainProgram = "yarr";
+    platforms = platforms.all;
+  };
+}