Fix streaming for z-ai in anthropic provider, add preliminary support for tool call streaming. Only reporting argument string deltas, not partial JSON objects

packages/ai/src/agent/tools/calculate.ts

@@ -0,0 +1,34 @@
+import type { AgentTool } from "../../agent";
+
+export interface CalculateResult {
+	output: string;
+	details: undefined;
+}
+
+export function calculate(expression: string): CalculateResult {
+	try {
+		const result = new Function("return " + expression)();
+		return { output: `${expression} = ${result}`, details: undefined };
+	} catch (e: any) {
+		throw new Error(e.message || String(e));
+	}
+}
+
+export const calculateTool: AgentTool<undefined> = {
+	label: "Calculator",
+	name: "calculate",
+	description: "Evaluate mathematical expressions",
+	parameters: {
+		type: "object",
+		properties: {
+			expression: {
+				type: "string",
+				description: "The mathematical expression to evaluate",
+			},
+		},
+		required: ["expression"],
+	},
+	execute: async (args: { expression: string }) => {
+		return calculate(args.expression);
+	},
+};