diff --git a/docs/SUMMARY.md b/docs/SUMMARY.md
index 82760dee..9bfe6790 100644
--- a/docs/SUMMARY.md
+++ b/docs/SUMMARY.md
@@ -11,6 +11,7 @@
 
 ## Guides
 
+- [Guides](guides/README.md)
 - [Market orders](guides/market-orders.md)
 - [Agent wallets and vaults](guides/agent-wallets-and-vaults.md)
 - [Browser wallets](guides/browser-wallets.md)
@@ -18,4 +19,5 @@
 
 ## Reference
 
+- [Reference](reference/README.md)
 - [Known documentation drift](reference/known-drift.md)
diff --git a/docs/guides/README.md b/docs/guides/README.md
index 6ae1da70..6bc39131 100644
--- a/docs/guides/README.md
+++ b/docs/guides/README.md
@@ -1,2 +1 @@
 # guides
-
diff --git a/docs/reference/README.md b/docs/reference/README.md
index d3673bac..c7704085 100644
--- a/docs/reference/README.md
+++ b/docs/reference/README.md
@@ -1,2 +1 @@
 # reference
-
diff --git a/src/signing/_fastWallet.ts b/src/signing/_fastWallet.ts
index 096bb100..b2f06663 100644
--- a/src/signing/_fastWallet.ts
+++ b/src/signing/_fastWallet.ts
@@ -43,10 +43,17 @@ let fallbackWarningShown = false;
  * Dynamically imports `tiny-secp256k1`, returning `undefined` when the optional dependency is
  * missing or unusable. The shape check guards against a partially linked install the same way the
  * `try` guards against an absent one: both route to the viem/noble fallback.
+ *
+ * Exported (never from `mod.ts`) so tests can drive the failure arms through the same code the
+ * real path uses: ESM module records are immutable, so a rejecting or partially linked real
+ * import cannot be simulated any other way — see {@linkcode _setEccLoaderForTests} for why module
+ * mocking is not an option. Production calls always take the default real import.
  */
-async function loadTinySecp256k1(): Promise<TinySecp256k1 | undefined> {
+export async function loadTinySecp256k1(
+  importEcc: () => Promise<unknown> = () => import("tiny-secp256k1"),
+): Promise<TinySecp256k1 | undefined> {
   try {
-    const ecc = await import("tiny-secp256k1");
+    const ecc = (await importEcc()) as TinySecp256k1;
     if (
       typeof ecc.signRecoverable !== "function" ||
       typeof ecc.pointFromScalar !== "function" ||
diff --git a/tests/signing/fastWallet.test.ts b/tests/signing/fastWallet.test.ts
index f6e8979b..21d847fe 100644
--- a/tests/signing/fastWallet.test.ts
+++ b/tests/signing/fastWallet.test.ts
@@ -26,7 +26,7 @@ import {
   signUserSignedAction,
 } from "@bloxwap/hyperliquid/signing";
 import { ApproveAgentTypes } from "@bloxwap/hyperliquid/api/exchange";
-import { _setEccLoaderForTests } from "../../src/signing/_fastWallet.ts";
+import { _setEccLoaderForTests, loadTinySecp256k1 } from "../../src/signing/_fastWallet.ts";
 
 // --- Fixtures (same shapes as tests/signing/fastDigest.test.ts) --------------
 
@@ -276,6 +276,38 @@ describe("createFastLocalWallet() WASM module validation", () => {
   });
 });
 
+// --- Real loader failure arms ---------------------------------------------------
+
+describe("loadTinySecp256k1() failure arms", () => {
+  test("returns undefined when the real import rejects (dependency absent)", async () => {
+    // The same code path the default call takes: a rejecting import lands in the catch arm.
+    await expect(loadTinySecp256k1(() => Promise.reject(new Error("Cannot find module")))).resolves.toBeUndefined();
+  });
+
+  test("returns undefined when the module is partially linked (shape check)", async () => {
+    // Missing one of the three required functions — the shape guard routes to the fallback.
+    await expect(
+      loadTinySecp256k1(() =>
+        Promise.resolve({ signRecoverable: () => new Uint8Array(65), pointFromScalar: () => new Uint8Array(33) }),
+      ),
+    ).resolves.toBeUndefined();
+  });
+
+  test("returns the module when the shape check passes", async () => {
+    const ecc = {
+      isPrivate: () => true,
+      pointFromScalar: () => new Uint8Array(33),
+      signRecoverable: () => ({ signature: new Uint8Array(64), recoveryId: 0 }),
+    };
+    await expect(loadTinySecp256k1(() => Promise.resolve(ecc))).resolves.toBe(ecc);
+  });
+
+  test("the default import resolves to the real tiny-secp256k1", async () => {
+    const ecc = await loadTinySecp256k1();
+    expect(typeof ecc?.signRecoverable).toBe("function");
+  });
+});
+
 // --- JSON-RPC wallets stay untouched --------------------------------------------
 
 describe("createFastLocalWallet() alongside JSON-RPC wallets", () => {