feat: add routed online search providers

tests/tavily-override.test.ts

@@ -0,0 +1,22 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { prefixTavilyTool } from "../extensions/tavily-tool-prefix.ts";
+
+test("Tavily override prefixes tool identity and internal tool references", () => {
+	const tool = prefixTavilyTool({
+		name: "web_search",
+		label: "Web Search",
+		description: "Use web_search, then web_fetch with Tavily.",
+		promptSnippet: "Call web_search.",
+		promptGuidelines: ["Use web_fetch after web_search."],
+		parameters: {} as never,
+		execute: async () => ({ content: [{ type: "text" as const, text: "ok" }] }),
+	});
+
+	assert.equal(tool.name, "tavily_web_search");
+	assert.equal(tool.label, "Tavily Web Search");
+	assert.equal(tool.description, "Use tavily_web_search, then tavily_web_fetch with Tavily.");
+	assert.equal(tool.promptSnippet, "Call tavily_web_search.");
+	assert.deepEqual(tool.promptGuidelines, ["Use tavily_web_fetch after tavily_web_search."]);
+});