diff --git a/js/nostr/client.js b/js/nostr/client.js
index e7fa1fd2..c1452801 100644
--- a/js/nostr/client.js
+++ b/js/nostr/client.js
@@ -173,7 +173,7 @@ import {
   readStoredSessionActorEntry,
   isSessionActor,
 } from "./sessionActor.js";
-import { HEX64_REGEX, normalizeHexHash } from "../utils/hex.js";
+import { HEX64_REGEX, normalizeHexHash, bytesToHex } from "../utils/hex.js";
 import {
   NIP46_RPC_KIND,
   NIP46_HANDSHAKE_TIMEOUT_MS,
diff --git a/js/utils/hex.js b/js/utils/hex.js
index 49307eb0..247ead81 100644
--- a/js/utils/hex.js
+++ b/js/utils/hex.js
@@ -12,6 +12,16 @@ export function normalizeHexString(value) {
 export const normalizeHexId = normalizeHexString;
 export const normalizeHexPubkey = normalizeHexString;
 
+// Lowercase hex encoding of a byte array (e.g. a generated secret key).
+export function bytesToHex(bytes) {
+  if (!bytes) {
+    return "";
+  }
+  return Array.from(bytes)
+    .map((byte) => byte.toString(16).padStart(2, "0"))
+    .join("");
+}
+
 export function normalizeHexHash(value) {
   if (value === undefined || value === null) {
     return "";
diff --git a/tests/nip17-send-gift-wrap.test.mjs b/tests/nip17-send-gift-wrap.test.mjs
new file mode 100644
index 00000000..56ef3beb
--- /dev/null
+++ b/tests/nip17-send-gift-wrap.test.mjs
@@ -0,0 +1,151 @@
+// Sending a NIP-17 DM (kind 1059 gift wrap) must generate an ephemeral wrapper
+// keypair. That keygen hex-encodes the generated secret via bytesToHex; a
+// missing import made bytesToHex throw (swallowed into "") so keygen returned
+// null and every NIP-17 send failed with `nip17-keygen-failed`. The legacy
+// (kind 4 / NIP-04) send tests delete nip44Encrypt, so they never exercised
+// this path. This test forces the NIP-17 path and asserts a gift wrap is built
+// and published.
+//
+// test_integrity_note:
+//   change_type: ["new_tests"]
+//   scenarios:
+//     - id: SCN-nip17-send-gift-wrap
+//       given: "a nip44-capable signer and known DM relays"
+//       when: "sendDirectMessage is called with useNip17:true"
+//       then: "it resolves ok and publishes a kind-1059 gift wrap (no keygen failure)"
+//   observable_outcomes:
+//     - "result.ok === true (not { error: 'nip17-keygen-failed' })"
+//     - "a kind 1059 gift-wrap event is published to the recipient relay"
+//   determinism_controls:
+//     - "real nostr-tools injected; pool.publish/list stubbed; relay hints supplied"
+//   anti_cheat_rationale:
+//     prevents: ["hard-coded return value", "over-mocking internal logic"]
+//   relaxation:
+//     did_relax_any_assertion: false
+
+import assert from "node:assert/strict";
+import test, { after } from "node:test";
+
+const RELAY_URL = "wss://relay.nip17.test";
+
+after(() => {
+  setTimeout(() => process.exit(0), 100);
+});
+
+test("sendDirectMessage (NIP-17) builds and publishes a kind-1059 gift wrap", async () => {
+  const previousCanonical = globalThis.__BITVID_CANONICAL_NOSTR_TOOLS__;
+  const previousNostrTools = globalThis.NostrTools;
+  const previousReady = globalThis.nostrToolsReady;
+
+  const nostrTools = await import("nostr-tools");
+  const canonicalTools = { ...nostrTools };
+
+  try {
+    globalThis.__BITVID_CANONICAL_NOSTR_TOOLS__ = canonicalTools;
+    globalThis.NostrTools = canonicalTools;
+    globalThis.nostrToolsReady = Promise.resolve({ ok: true, value: canonicalTools });
+
+    const [{ nostrClient }, { getActiveSigner, clearActiveSigner }] =
+      await Promise.all([
+        import("../js/nostrClientFacade.js"),
+        import("../js/nostr/client.js"),
+      ]);
+
+    const previousPool = nostrClient.pool;
+    const previousRelays = nostrClient.relays;
+    const previousPubkey = nostrClient.pubkey;
+
+    const publishInvocations = [];
+    nostrClient.pool = {
+      publish(urls, event) {
+        publishInvocations.push({ urls, event });
+        return {
+          on(eventName, handler) {
+            if (eventName === "ok") setTimeout(() => handler(), 0);
+            return true;
+          },
+        };
+      },
+      list() {
+        return Promise.resolve([]);
+      },
+    };
+    nostrClient.relays = [RELAY_URL];
+    nostrClient.readRelays = [RELAY_URL];
+    nostrClient.writeRelays = [RELAY_URL];
+
+    const senderSecret = canonicalTools.generateSecretKey();
+    const senderPubkey = canonicalTools.getPublicKey(senderSecret);
+    const recipientSecret = canonicalTools.generateSecretKey();
+    const recipientPubkey = canonicalTools.getPublicKey(recipientSecret);
+
+    await nostrClient.registerPrivateKeySigner({
+      privateKey: canonicalTools.utils.bytesToHex(senderSecret),
+      pubkey: senderPubkey,
+    });
+    nostrClient.pubkey = senderPubkey;
+
+    const signer = getActiveSigner();
+    // Keep nip44 (so the NIP-17 path is taken) and give it a working impl.
+    signer.signEvent = (event) => {
+      const finalized = canonicalTools.finalizeEvent(event, senderSecret);
+      return { ...event, id: finalized.id, sig: finalized.sig };
+    };
+    signer.nip44Encrypt = async (peerPubkey, plaintext) => {
+      const key = canonicalTools.nip44.v2.utils.getConversationKey(
+        senderSecret,
+        peerPubkey,
+      );
+      return canonicalTools.nip44.v2.encrypt(plaintext, key);
+    };
+
+    const result = await nostrClient.sendDirectMessage(
+      recipientPubkey,
+      "nip17 gift wrap smoke test",
+      {
+        useNip17: true,
+        recipientRelayHints: [RELAY_URL],
+        senderRelayHints: [RELAY_URL],
+      },
+    );
+
+    assert.equal(
+      result.ok,
+      true,
+      `NIP-17 send should succeed, got: ${JSON.stringify(result)}`,
+    );
+    assert.notEqual(
+      result.error,
+      "nip17-keygen-failed",
+      "ephemeral wrapper keygen must not fail",
+    );
+
+    const giftWraps = publishInvocations.filter(
+      ({ event }) => event?.kind === 1059,
+    );
+    assert.ok(
+      giftWraps.length >= 1,
+      "at least one kind-1059 gift wrap should be published",
+    );
+    // A gift wrap is signed by a fresh ephemeral key, never the sender's.
+    assert.notEqual(
+      giftWraps[0].event.pubkey,
+      senderPubkey,
+      "gift wrap must be authored by the ephemeral wrapper key, not the sender",
+    );
+
+    signer.signEvent = undefined;
+    signer.nip44Encrypt = undefined;
+    clearActiveSigner();
+    nostrClient.pool = previousPool;
+    nostrClient.relays = previousRelays;
+    nostrClient.pubkey = previousPubkey;
+  } finally {
+    if (previousCanonical === undefined) delete globalThis.__BITVID_CANONICAL_NOSTR_TOOLS__;
+    else globalThis.__BITVID_CANONICAL_NOSTR_TOOLS__ = previousCanonical;
+    if (previousNostrTools === undefined) delete globalThis.NostrTools;
+    else globalThis.NostrTools = previousNostrTools;
+    if (previousReady === undefined) delete globalThis.nostrToolsReady;
+    else globalThis.nostrToolsReady = previousReady;
+  }
+});