diff --git a/CHANGELOG.md b/CHANGELOG.md
index 19c1bc1..7077833 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -62,6 +62,13 @@ Newest entries on top, within each tool.
 
 ## aikit
 
+### 1.15.5 — 2026-07-03
+- **Fix: invalid virtual key no longer silently accepted during model discovery** (POK-88).
+  Gateway HTTP clients (`gateway models`, `gateway on`, passthrough probes, doctor
+  reachability) sent both `Authorization: Bearer` and `x-api-key`. On gateways that
+  enforce Bearer but accept any `x-api-key`, a typo'd key looked valid. Clients now
+  send Bearer only, matching LiteLLM virtual-key semantics.
+
 ### 1.15.4 — 2026-07-02
 - **Fix: five POK-65 agents falsely showed "needs auth" when authenticated** (POK-78).
   `auggie`, `devin`, `qodo`, `openinterpreter`, and `plandex` were registered without
diff --git a/aikit b/aikit
index 8ca4a2b..245d08f 100755
--- a/aikit
+++ b/aikit
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 """
-aikit — AI Coding Agent CLI Installer & Manager  v1.15.4
+aikit — AI Coding Agent CLI Installer & Manager  v1.15.5
 Install, update, authenticate, and manage 31 AI coding agent CLIs from one tool.
 
 Architecture:
@@ -52,7 +52,7 @@ from rich.progress import Progress, SpinnerColumn, TextColumn
 from rich.table import Table
 from rich.text import Text
 
-__version__ = "1.15.4"
+__version__ = "1.15.5"
 
 import scriptkit as sk
 
@@ -3222,6 +3222,20 @@ def _normalize_gateway_url(url):
 
 
 # --- model discovery client ------------------------------------------------
+def _gateway_auth_headers(key):
+    """Auth headers for gateway HTTP clients.
+
+    LiteLLM virtual keys authenticate via ``Authorization: Bearer``. Also sending
+    ``x-api-key`` can mask a rejected key on gateways that enforce Bearer but accept
+    any ``x-api-key`` (POK-88).
+    """
+    return {
+        "Authorization": f"Bearer {key}",
+        "Accept": "application/json",
+        "User-Agent": f"aikit/{__version__}",
+    }
+
+
 def _gateway_get_json(url, key, timeout=20):
     """GET ``url`` with gateway auth headers; return parsed JSON.
 
@@ -3230,12 +3244,7 @@ def _gateway_get_json(url, key, timeout=20):
     """
     import requests
 
-    headers = {
-        "Authorization": f"Bearer {key}",
-        "x-api-key": key,
-        "Accept": "application/json",
-        "User-Agent": f"aikit/{__version__}",
-    }
+    headers = _gateway_auth_headers(key)
     try:
         resp = requests.get(url, headers=headers, timeout=timeout)
     except requests.exceptions.RequestException as e:
@@ -3346,12 +3355,7 @@ def _probe_status(url, key, *, timeout=6):
     """
     import requests
 
-    headers = {
-        "Authorization": f"Bearer {key}",
-        "x-api-key": key,
-        "Accept": "application/json",
-        "User-Agent": f"aikit/{__version__}",
-    }
+    headers = _gateway_auth_headers(key)
     try:
         return requests.get(url, headers=headers, timeout=timeout).status_code
     except requests.exceptions.RequestException:
diff --git a/tests/test_aikit_gateway.py b/tests/test_aikit_gateway.py
index 3eb5672..67315e0 100644
--- a/tests/test_aikit_gateway.py
+++ b/tests/test_aikit_gateway.py
@@ -148,6 +148,33 @@ def fake_getter(url, key):
         aikit.discover_models("https://gw", "k", getter=fake_getter)
 
 
+def test_gateway_auth_headers_are_bearer_only(aikit):
+    headers = aikit._gateway_auth_headers("sk-test")
+    assert headers["Authorization"] == "Bearer sk-test"
+    assert "x-api-key" not in headers
+
+
+def test_gateway_get_json_rejects_invalid_key_without_x_api_key_mask(aikit, monkeypatch):
+    """POK-88: a lenient x-api-key must not bypass Bearer enforcement."""
+    import requests
+
+    def fake_get(url, headers=None, timeout=None):
+        auth = (headers or {}).get("Authorization", "")
+        if (headers or {}).get("x-api-key"):
+            # Gateway accepts any x-api-key — would have masked a bad bearer if sent.
+            return type("Resp", (), {"status_code": 200, "ok": True,
+                                      "json": lambda self: {"data": []}})()
+        if auth == "Bearer sk-valid":
+            return type("Resp", (), {"status_code": 200, "ok": True,
+                                      "json": lambda self: {"data": []}})()
+        return type("Resp", (), {"status_code": 401, "ok": False})()
+
+    monkeypatch.setattr(requests, "get", fake_get)
+    with pytest.raises(aikit.AikitError, match="rejected the key"):
+        aikit._gateway_get_json("https://gw/v1/models", "sk-bogus")
+    aikit._gateway_get_json("https://gw/v1/models", "sk-valid")
+
+
 def test_providers_in_use(aikit):
     models = ["openai/gpt-4o", "anthropic/claude", "bogusprov/x", "bare-model"]
     detail = {"openai/gpt-4o": {"provider": "openai"}}