diff --git a/src/ml/imf/index.ts b/src/ml/imf/index.ts
index b865c7b..30e36bd 100644
--- a/src/ml/imf/index.ts
+++ b/src/ml/imf/index.ts
@@ -18,4 +18,12 @@ export {
 } from "./registry.js"
 export { pickTier, warmUp, type TierCandidate } from "./tiers.js"
 export { normalizeArabicInput, repetitionGuardCut } from "./guards.js"
-export { encode, decode, BYTE_OFFSET, EOS_ID, PAD_ID, UNK_ID } from "./tokens.js"
+export {
+  encode,
+  decode,
+  firstAlternates,
+  BYTE_OFFSET,
+  EOS_ID,
+  PAD_ID,
+  UNK_ID,
+} from "./tokens.js"
diff --git a/test/ml/public-surface.test.ts b/test/ml/public-surface.test.ts
new file mode 100644
index 0000000..15ff494
--- /dev/null
+++ b/test/ml/public-surface.test.ts
@@ -0,0 +1,13 @@
+import { describe, expect, it } from "vitest"
+import * as ml from "../../src/ml/index.js"
+
+// Public-surface guard: the decode-contract helpers must be reachable
+// through the package barrel, not only via source-tree imports.
+// (npm 5.8.0 shipped tokens.js with firstAlternates but the imf
+// barrel never re-exported it — unreachable by any documented import.)
+describe("ml public surface", () => {
+  it("exposes imf.firstAlternates through the barrel", () => {
+    expect(typeof ml.imf.firstAlternates).toBe("function")
+    expect(ml.imf.firstAlternates("a/b c")).toBe("a c")
+  })
+})