feat: enable MCP servers and add happy-coder

- Enables official MCP servers (fetch, playwright, stackexchange, arxiv)
- Adds Charlie MCP servers (memory, comunica)
- Adds claudezilla MCP server
- Adds happy-coder mobile client from nixpkgs master
- Adds nodejs_22 for MCP server runtime

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

home/by-host/endurance/config/dev.nix

@@ -24,6 +24,9 @@
     nodePackages.typescript-language-server
     nil # nix lsp
 
+    # Node.js for MCP servers
+    nodejs_22
+
     # trurl # Parsing and manipulating URLs via CLI
     pandoc # Document converter
     ripgrep # Grep file search
@@ -39,6 +42,7 @@
     gitui
     tea
     harbor.agent-deck # Terminal session manager for AI coding agents
+    happy-coder # Claude Code mobile client (happy.engineering)
     harbor.oryx # TUI for sniffing network traffic using eBPF
 
     # BMAD
@@ -83,33 +87,48 @@
       enable = true;
       # package = inputs.unstable.${system}.claude-code;
 
-      # mcpServers = {
-      #   fetch = {
-      #     args = ["-y" "@modelcontextprotocol/server-fetch"];
-      #     command = "npx";
-      #     type = "stdio";
-      #   };
-      #   playwright = {
-      #     args = ["-y" "@modelcontextprotocol/server-playwright"];
-      #     command = "npx";
-      #     type = "stdio";
-      #   };
-      #   stackexchange = {
-      #     args = ["-y" "mcp-server-stackexchange"];
-      #     command = "npx";
-      #     type = "stdio";
-      #   };
-      #   arxiv = {
-      #     args = ["-y" "mcp-server-arxiv"];
-      #     command = "npx";
-      #     type = "stdio";
-      #   };
-      #   claudezilla = {
-      #     command = "bun";
-      #     args = ["/home/toph/code/vendor/claudezilla/mcp/server.js"];
-      #     type = "stdio";
-      #   };
-      # };
+      mcpServers = {
+        # Official MCP servers (require Node.js)
+        fetch = {
+          command = "npx";
+          args = ["-y" "@modelcontextprotocol/server-fetch"];
+          type = "stdio";
+        };
+        playwright = {
+          command = "npx";
+          args = ["-y" "@modelcontextprotocol/server-playwright"];
+          type = "stdio";
+        };
+        stackexchange = {
+          command = "npx";
+          args = ["-y" "mcp-server-stackexchange"];
+          type = "stdio";
+        };
+        arxiv = {
+          command = "npx";
+          args = ["-y" "mcp-server-arxiv"];
+          type = "stdio";
+        };
+
+        # Custom MCP servers
+        claudezilla = {
+          command = "bun";
+          args = ["/home/toph/code/vendor/claudezilla/mcp/server.js"];
+          type = "stdio";
+        };
+
+        # Charlie MCP servers (local)
+        charlie-memory = {
+          command = "bun";
+          args = ["/home/toph/agent/mcp/memory/index.js"];
+          type = "stdio";
+        };
+        charlie-comunica = {
+          command = "bun";
+          args = ["/home/toph/agent/mcp/comunica/index.js"];
+          type = "stdio";
+        };
+      };
     };
   };
 }

overlays/unstable.nix

@@ -17,5 +17,5 @@
     # open-webui
     ;
 
-  inherit (channels.master) install-nothing marimo;
+  inherit (channels.master) install-nothing marimo happy-coder;
 }