feat(ai-vercel-adapter): add Vercel AI adapter

Author: gwardwell

packages/ai-vercel-adapter/src/VercelAIAdapter.ts

@@ -0,0 +1,55 @@
+import { ApolloLink } from "@apollo/client";
+import { type LanguageModel, generateObject } from "ai";
+import { AIAdapter } from "@apollo/client-ai";
+import { isFormattedExecutionResult } from "@apollo/client/utilities";
+
+namespace VercelAIAdapter {
+  export interface Options extends AIAdapter.Options {
+    model: LanguageModel;
+  }
+}
+
+type GenerateObjectOptions = {
+  model: LanguageModel;
+  mode: "json";
+  prompt: string;
+  system?: string;
+  output: "no-schema";
+};
+
+export class VercelAIAdapter extends AIAdapter {
+  public model: LanguageModel;
+
+  constructor(options: VercelAIAdapter.Options) {
+    super(options);
+
+    this.model = options.model;
+  }
+
+  public async generateResponseForOperation(
+    operation: ApolloLink.Operation,
+    prompt: string
+  ): Promise<AIAdapter.Result> {
+    const promptOptions: GenerateObjectOptions = {
+      mode: "json",
+      model: this.model,
+      prompt: this.createPrompt(operation, prompt),
+      system: this.systemPrompt,
+      output: "no-schema",
+    };
+
+    return generateObject(promptOptions).then(
+      ({ object: result, finishReason, usage, warnings }) => {
+        if (!result || typeof result !== "object") {
+          return { data: null };
+        }
+        // Type guard to ensure result is a valid FormattedExecutionResult
+        if (isFormattedExecutionResult(result)) {
+          return result;
+        }
+        // Fallback: wrap in data property if not a valid execution result
+        return { data: result };
+      }
+    );
+  }
+}