perf(js): load the ElevenLabs SDK only when voice runs

javascript/examples/openai-realtime-demo/package.json

@@ -11,7 +11,8 @@
     "format": "pnpm lint --fix"
   },
   "dependencies": {
-    "@openai/agents": "^0.16.0"
+    "@openai/agents": "^0.16.0",
+    "zod": "^4.1.13"
   },
   "devDependencies": {
     "@types/node": "^26.2.0",

javascript/src/voice/__tests__/elevenlabs-sdk.test.ts

@@ -0,0 +1,76 @@
+/**
+ * The ElevenLabs SDK must stay out of the module graph until voice runs.
+ *
+ * A module-scope `import ... from "@elevenlabs/elevenlabs-js"` anywhere under
+ * `src/` puts it back into every consumer of the package, because `index.ts`
+ * re-exports the voice namespace. That cost 4,972 modules and 237MB of RSS on
+ * a plain `import "@langwatch/scenario"`, paid by text-only scenarios too.
+ *
+ * This is a source scan rather than a runtime check because the regression is
+ * a static import, and a static import is exactly what a runtime probe of an
+ * already-bundled build can no longer distinguish.
+ */
+import { readdirSync, readFileSync, statSync } from "node:fs";
+import { join, relative, resolve } from "node:path";
+import { describe, expect, it } from "vitest";
+
+/** javascript/src, from src/voice/__tests__/. */
+const SRC = resolve(__dirname, "../..");
+
+/** The seam is the one module allowed to name the SDK, and only in a body. */
+const SEAM = "voice/elevenlabs-sdk.ts";
+
+function sourceFiles(dir: string): string[] {
+  return readdirSync(dir).flatMap((entry) => {
+    const path = join(dir, entry);
+    if (statSync(path).isDirectory()) {
+      return entry === "__tests__" ? [] : sourceFiles(path);
+    }
+    return path.endsWith(".ts") && !path.endsWith(".d.ts") ? [path] : [];
+  });
+}
+
+/**
+ * Every specifier reached by a static import, in all the forms that load a
+ * module: named, type-only, re-export, and bare side-effect.
+ *
+ * A named import may wrap over several lines, so the `from` pattern has to
+ * cross newlines. What stops it running into a function body and finding the
+ * seam's own `import(...)` is excluding `;`, `(` and `)`: every dynamic import
+ * sits inside a call, and no static import declaration contains one.
+ *
+ * `matchAll` rather than `.test()`, because a `g`-flagged regex carries
+ * `lastIndex` between calls and would skip every second offending file.
+ */
+const IMPORT_FROM = /^[ \t]*(?:import|export)\s[^;()]*?\bfrom\s*["']([^"']+)["']/gm;
+const IMPORT_BARE = /^[ \t]*import\s+["']([^"']+)["']/gm;
+
+function staticallyImportsSdk(text: string): boolean {
+  for (const pattern of [IMPORT_FROM, IMPORT_BARE]) {
+    for (const [, specifier] of text.matchAll(pattern)) {
+      if (specifier?.startsWith("@elevenlabs/")) return true;
+    }
+  }
+  return false;
+}
+
+describe("given the package is imported without running voice", () => {
+  describe("when a consumer imports the entry point", () => {
+    it("loads no ElevenLabs module, because nothing imports the SDK statically", () => {
+      const offenders = sourceFiles(SRC)
+        .map((path) => ({ path, text: readFileSync(path, "utf8") }))
+        .filter(({ text }) => staticallyImportsSdk(text))
+        .map(({ path }) => relative(SRC, path));
+
+      expect(
+        offenders,
+        `these modules import the ElevenLabs SDK at module scope, which pulls ~5k modules into every consumer. Route the call through ${SEAM} instead`,
+      ).toEqual([]);
+    });
+
+    it("keeps the SDK reachable through the seam, so voice still works", () => {
+      const seam = readFileSync(resolve(SRC, SEAM), "utf8");
+      expect(seam).toMatch(/await import\(\s*\n?\s*["']@elevenlabs\//);
+    });
+  });
+});