ai-sdk rewrite (#1021)

Author: ibolmo

internal/golden/README.md

@@ -7,6 +7,7 @@ These test files validate the Braintrust SDK's integration with different AI pro
 - `anthropic.ts` - Tests for Anthropic/Claude integration
 - `openai.ts` - Tests for OpenAI integration
 - `google_genai.py` - Tests for Google Generative AI integration
+- `ai-sdk.ts` - Tests for AI SDK (Vercel) integration across multiple versions
 
 Each test suite validates:
 
@@ -19,6 +20,47 @@ Each test suite validates:
 - Tool use and function calling
 - Mixed content types
 
+## AI SDK Version Testing
+
+The `ai-sdk.ts` test file can be run against multiple versions of the Vercel AI SDK (v3, v4, v5, and v6 beta) to ensure compatibility across versions. Each version has its own directory with compatible provider packages:
+
+- `ai-sdk-v3/` - AI SDK v3.x with compatible providers
+- `ai-sdk-v4/` - AI SDK v4.x with compatible providers
+- `ai-sdk-v5/` - AI SDK v5.x with compatible providers
+- `ai-sdk-v6/` - AI SDK v6.x beta with compatible providers
+
+### Running AI SDK Version Tests
+
+```bash
+# Install dependencies for a specific version
+cd ai-sdk-v5
+pnpm install --ignore-workspace
+
+# Run the tests
+npx tsx ai-sdk.ts
+
+# Or test another version
+cd ../ai-sdk-v3
+pnpm install --ignore-workspace
+npx tsx ai-sdk.ts
+```
+
+### Updating Test Files
+
+When you update the main `ai-sdk.ts` file, sync it to all version directories:
+
+```bash
+./sync-test-file.sh
+```
+
+Or manually:
+
+```bash
+for dir in ai-sdk-v{3,4,5,6}; do
+  cp ai-sdk.ts $dir/ai-sdk.ts
+done
+```
+
 ## Running Tests
 
 ### TypeScript Tests