feat: use vercel ai gateway (#38)

utils/ai/client.ts

@@ -0,0 +1,52 @@
+import { generateText, tool, jsonSchema } from 'ai';
+import { BaseTool } from './tool';
+import type { JSONSchema7 } from 'json-schema';
+
+export async function getMessage<T>(text: string, baseTool: BaseTool) {
+  console.info('Vercel AI Gateway request with text: ', text);
+
+  try {
+    const { steps } = await generateText({
+      model: 'anthropic/claude-sonnet-4.5',
+      temperature: 1,
+      tools: {
+        [baseTool.name]: tool({
+          description: baseTool.input_schema.description || '',
+          inputSchema: jsonSchema(baseTool.input_schema as JSONSchema7),
+          execute: async args => args
+        })
+      },
+      toolChoice: {
+        type: 'tool',
+        toolName: baseTool.name
+      },
+      prompt: text
+    });
+
+    console.info('Vercel AI Gateway response steps: ', steps);
+
+    const toolCalls = steps.flatMap(step => step.toolCalls);
+
+    if (!toolCalls || toolCalls.length === 0) {
+      throw new Error('No tool calls found in response');
+    }
+
+    const typedCall = toolCalls[0] as unknown as {
+      toolName: string;
+      input: Record<string, unknown>;
+    };
+
+    console.info('Tool call input: ', typedCall.input);
+
+    if (typedCall.toolName !== baseTool.name) {
+      throw new Error(
+        `Expected tool ${baseTool.name} but got ${typedCall.toolName}`
+      );
+    }
+
+    return typedCall.input as T;
+  } catch (error) {
+    console.error('Vercel AI Gateway error: ', error);
+    throw new Error('Failed to get message from AI Gateway');
+  }
+}