diff --git a/deploy/scripts/register-challenge-backends.sh b/deploy/scripts/register-challenge-backends.sh
index fc8074e69..d3d2e14a3 100755
--- a/deploy/scripts/register-challenge-backends.sh
+++ b/deploy/scripts/register-challenge-backends.sh
@@ -52,9 +52,12 @@ register_one() {
   local payload http body token
   local -a auth=()
   token="$(resolve_admin_token || true)"
-  if [[ -n "${token}" ]]; then
-    auth=(-H "Authorization: Bearer ${token}")
+  if [[ -z "${token}" ]]; then
+    echo "register-challenge-backends: missing gateway admin token" >&2
+    echo "  set BASE_GATEWAY_ADMIN_TOKEN or deploy/secrets/gateway_admin_token" >&2
+    return 1
   fi
+  auth=(-H "Authorization: Bearer ${token}")
   payload="$(printf '{"challenge_id":"%s","base_url":"%s","weight":1}' "$challenge_id" "$base_url")"
   if [[ "$COMPOSE_MODE" -eq 1 ]]; then
     body="$(docker compose -f docker-compose.yml \
@@ -62,12 +65,12 @@ register_one() {
       exec -T gateway \
       curl -sS -w '\n%{http_code}' -X POST http://127.0.0.1:8080/v1/admin/backends \
       -H 'content-type: application/json' \
-      ${auth[@]+"${auth[@]}"} \
+      "${auth[@]}" \
       -d "$payload" 2>/dev/null || true)"
   else
     body="$(curl -sS -w '\n%{http_code}' -X POST "${GATEWAY_URL%/}/v1/admin/backends" \
       -H 'content-type: application/json' \
-      ${auth[@]+"${auth[@]}"} \
+      "${auth[@]}" \
       -d "$payload" 2>/dev/null || true)"
   fi
   http="$(printf '%s' "$body" | tail -n1)"
diff --git a/deploy/scripts/remote-deploy.sh b/deploy/scripts/remote-deploy.sh
index 0dbb25aed..bc17f0d99 100755
--- a/deploy/scripts/remote-deploy.sh
+++ b/deploy/scripts/remote-deploy.sh
@@ -442,11 +442,49 @@ if [[ '$ROLE' == 'master' ]]; then
   # The gateway races this script on boot, so retry until registration sticks,
   # then prove proxy routing end-to-end: a missed reseed leaves /challenge/*
   # at 503 while /healthz stays green. Both must fail the deploy loudly.
+  # Gateway /v1/admin/* requires Authorization: Bearer (gateway_admin_token).
   echo "remote-deploy: registering challenge backends"
   reseed_ok=0
   for attempt in \$(seq 1 15); do
     if python3 - <<'PY'
-import json, sys, urllib.request, urllib.error
+import json, os, sys, urllib.error, urllib.request
+from pathlib import Path
+
+def resolve_admin_token() -> str:
+    token = (os.environ.get("BASE_GATEWAY_ADMIN_TOKEN") or "").strip()
+    if token:
+        return token
+    candidates = []
+    env_file = (os.environ.get("BASE_GATEWAY_ADMIN_TOKEN_FILE") or "").strip()
+    if env_file:
+        candidates.append(Path(env_file))
+    # remote-deploy cds to REMOTE_DIR (/opt/base); secrets live beside the tree.
+    candidates.extend(
+        [
+            Path("deploy/secrets/gateway_admin_token"),
+            Path("/opt/base/deploy/secrets/gateway_admin_token"),
+        ]
+    )
+    for path in candidates:
+        if path.is_file():
+            token = path.read_text(encoding="utf-8").strip()
+            if token:
+                return token
+    return ""
+
+token = resolve_admin_token()
+if not token:
+    print(
+        "ERROR: gateway admin token missing "
+        "(set BASE_GATEWAY_ADMIN_TOKEN or deploy/secrets/gateway_admin_token)",
+        flush=True,
+    )
+    sys.exit(1)
+
+headers = {
+    "content-type": "application/json",
+    "Authorization": f"Bearer {token}",
+}
 backends = [
     ("prism", "http://prism-challenge:8092"),
     ("design", "http://design-challenge:8093"),
@@ -457,7 +495,7 @@ for cid, url in backends:
     req = urllib.request.Request(
         "http://127.0.0.1:8080/v1/admin/backends",
         data=payload,
-        headers={"content-type": "application/json"},
+        headers=headers,
         method="POST",
     )
     try:
diff --git a/docs/runbooks/staging-testnet-e2e.md b/docs/runbooks/staging-testnet-e2e.md
index 8e14b35d1..c257c0bf1 100644
--- a/docs/runbooks/staging-testnet-e2e.md
+++ b/docs/runbooks/staging-testnet-e2e.md
@@ -55,16 +55,20 @@ are registered. `remote-deploy.sh` (master) re-seeds automatically; to do it by
 hand:
 
 ```bash
-# From this repo (against a reachable gateway):
+# From this repo (against a reachable gateway; reads deploy/secrets/gateway_admin_token):
 GATEWAY_URL=http://staging.api.joinbase.ai ./deploy/scripts/register-challenge-backends.sh
 
-# Or on the droplet:
+# Or on the droplet (admin bearer required after #100):
+TOKEN=$(tr -d '[:space:]' </opt/base/deploy/secrets/gateway_admin_token)
 curl -fsS -X POST http://127.0.0.1:8080/v1/admin/backends \
   -H 'content-type: application/json' \
+  -H "Authorization: Bearer ${TOKEN}" \
   -d '{"challenge_id":"prism","base_url":"http://prism-challenge:8092","weight":1}'
 curl -fsS -X POST http://127.0.0.1:8080/v1/admin/backends \
   -H 'content-type: application/json' \
+  -H "Authorization: Bearer ${TOKEN}" \
   -d '{"challenge_id":"design","base_url":"http://design-challenge:8093","weight":1}'
+unset TOKEN
 curl -fsS http://staging.api.joinbase.ai/challenge/prism/health
 curl -fsS http://staging.api.joinbase.ai/challenge/design/health
 ```