Add Nix development environment and Claude guidance file (#4)

# Add Nix development environment and Claude.ai integration

This PR adds support for Nix development environments and improves Claude.ai integration:

1. Added a `CLAUDE.md` file that provides guidance to Claude Code when working with this repository, including:
   - Project overview and architecture explanation
   - Development commands and testing instructions
   - Environment variable documentation

2. Added Nix development environment support:
   - Created `flake.nix` and `flake.lock` for reproducible development environments
   - Configured development shell with bun, nodejs, and code quality tools
   - Added treefmt integration for consistent code formatting

3. Updated `.gitignore` to exclude Nix-related files:
   - `.direnv`
   - `.envrc`
   - `.claude`

These changes make it easier for developers using Nix to contribute to the project and improve the experience when using Claude Code with this repository.

Author: ThomasK33

.gitignore

@@ -32,3 +32,7 @@ report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
 
 # Finder (MacOS) folder config
 .DS_Store
+
+.direnv
+.envrc
+.claude

CLAUDE.md

@@ -0,0 +1,67 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+anyclaude is a proxy wrapper for Claude Code that enables using alternative LLM providers (OpenAI, Google, xAI, Azure) through the Anthropic API format. It intercepts Anthropic API calls and translates them to/from the Vercel AI SDK format for the specified provider.
+
+## Architecture
+
+The proxy works by:
+
+1. Spawning a local HTTP server that mimics the Anthropic API
+2. Intercepting `/v1/messages` requests containing `<provider>/<model>` format
+3. Converting Anthropic message format to AI SDK format
+4. Routing to the appropriate provider (OpenAI, Google, xAI, Azure)
+5. Converting responses back to Anthropic format
+6. Setting `ANTHROPIC_BASE_URL` to point Claude Code at the proxy
+
+Key components:
+
+- `src/main.ts`: Entry point that sets up providers and spawns Claude with proxy
+- `src/anthropic-proxy.ts`: HTTP server that handles request/response translation
+- `src/convert-anthropic-messages.ts`: Bidirectional message format conversion
+- `src/convert-to-anthropic-stream.ts`: Stream response conversion
+- `src/json-schema.ts`: Schema adaptation for different providers
+
+## Development Commands
+
+```bash
+# Install dependencies
+bun install
+
+# Build the project (creates dist/main.js with shebang)
+bun run build
+
+# The build command:
+# 1. Compiles TypeScript to CommonJS for Node.js compatibility
+# 2. Adds Node shebang for CLI execution
+```
+
+## Testing
+
+Test the proxy manually:
+
+```bash
+# Run in proxy-only mode to get the URL
+PROXY_ONLY=true bun run src/main.ts
+
+# Test with a provider
+OPENAI_API_KEY=your-key bun run src/main.ts --model openai/gpt-4
+```
+
+## Environment Variables
+
+Required for each provider:
+
+- `OPENAI_API_KEY` + optional `OPENAI_API_URL` for OpenAI/OpenRouter
+- `GOOGLE_API_KEY` + optional `GOOGLE_API_URL` for Google
+- `XAI_API_KEY` + optional `XAI_API_URL` for xAI
+- `AZURE_API_KEY` + optional `AZURE_API_URL` for Azure
+- `ANTHROPIC_API_KEY` + optional `ANTHROPIC_API_URL` for Anthropic passthrough
+
+Special modes:
+
+- `PROXY_ONLY=true`: Run proxy server without spawning Claude Code
+

README.md

@@ -14,7 +14,7 @@ Use Claude Code with OpenAI, Google, xAI, and other providers.
 
 ```sh
 # Use your favorite package manager (bun, pnpm, and npm are supported)
-$ pnpm install -g anyclaude 
+$ pnpm install -g anyclaude
 
 # anyclaude is a wrapper for the Claude CLI
 # `openai/`, `google/`, `xai/`, and `anthropic/` are supported

flake.lock

@@ -0,0 +1,55 @@
+{
+  description = "AnyClaude development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    treefmt-nix.url = "github:numtide/treefmt-nix";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, treefmt-nix }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+
+        treefmt = treefmt-nix.lib.evalModule pkgs {
+          projectRootFile = "flake.nix";
+          programs = {
+            nixpkgs-fmt.enable = true;
+            shfmt.enable = true;
+            shellcheck.enable = true;
+          };
+        };
+      in
+      {
+        # Format the source tree
+        formatter = treefmt.config.build.wrapper;
+
+        # Check formatting
+        checks.formatting = treefmt.config.build.check self;
+
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            # Primary runtime and package manager
+            bun
+
+            # Node.js for compatibility (required by some tools)
+            nodejs_22
+
+            # Code quality tools (already included by treefmt)
+            treefmt.config.build.wrapper
+
+            # Version control
+            git
+
+            # Utilities
+            jq
+            ripgrep
+            bat
+          ];
+
+          # Environment variables
+          NODE_ENV = "development";
+        };
+      });
+}

flake.nix

@@ -32,4 +32,4 @@
   "scripts": {
     "build": "bun build --target node --outfile dist/main.js ./src/main.ts --format cjs && sed -i '0,/^/s//#!\\/usr\\/bin\\/env node\\n/' ./dist/main.js"
   }
-}
+}