diff --git a/agent/vertex_adapter.py b/agent/vertex_adapter.py
index 6e425753f0..ac2658b662 100644
--- a/agent/vertex_adapter.py
+++ b/agent/vertex_adapter.py
@@ -226,3 +226,26 @@ def has_vertex_credentials() -> bool:
     if _resolve_project_override():
         return True
     return False
+
+
+def has_explicit_vertex_config() -> bool:
+    """True only when the user deliberately pointed Hermes at Vertex.
+
+    Stricter than :func:`has_vertex_credentials`, which also returns True for
+    an ambient ``GOOGLE_APPLICATION_CREDENTIALS`` path — a var commonly set
+    globally for unrelated GCP work. That ambient signal must NOT mark Vertex
+    "explicitly configured" for the model-picker gate, or a user who never set
+    Hermes up for Vertex would suddenly see it (and could spend against those
+    credentials). So this checks only Hermes-scoped signals:
+
+      * ``VERTEX_PROJECT_ID`` env or ``vertex.project_id`` in config.yaml
+        (``_resolve_project_override``), or
+      * a resolvable ``VERTEX_CREDENTIALS_PATH`` service-account file
+        (the Hermes-specific path var — NOT ``GOOGLE_APPLICATION_CREDENTIALS``).
+    """
+    if _resolve_project_override():
+        return True
+    sa_path = _get_secret("VERTEX_CREDENTIALS_PATH")
+    if sa_path and os.path.exists(sa_path):
+        return True
+    return False
diff --git a/hermes_cli/auth.py b/hermes_cli/auth.py
index 449588d539..cdc1f566c8 100644
--- a/hermes_cli/auth.py
+++ b/hermes_cli/auth.py
@@ -2009,6 +2009,39 @@ def is_provider_explicitly_configured(provider_id: str) -> bool:
     except Exception:
         pass
 
+    # 5. OAuth-token / cloud-SDK providers (Vertex AI, Bedrock) have NO API-key
+    # env var to detect in step 3 and mint short-lived tokens from ADC / a
+    # service account / the AWS SDK chain. The user "explicitly configures"
+    # them by writing non-secret routing settings into config.yaml
+    # (``vertex.project_id`` / a credentials path, ``bedrock.region``) rather
+    # than by pasting a key — so without this branch such a provider is only
+    # ever "explicitly configured" while it is the *current* provider, and it
+    # silently vanishes from explicit-only pickers (desktop chat model menu)
+    # otherwise. Treat the presence of that deliberate config as explicit.
+    #
+    # NOTE: this uses has_explicit_vertex_config(), NOT has_vertex_credentials()
+    # — the latter also counts an ambient GOOGLE_APPLICATION_CREDENTIALS path
+    # (commonly set globally for unrelated GCP work), which would mark Vertex
+    # explicit for users who never set Hermes up for it. Only Hermes-scoped
+    # signals (VERTEX_PROJECT_ID / vertex.project_id / VERTEX_CREDENTIALS_PATH)
+    # count here.
+    try:
+        if normalized in ("vertex", "google-vertex", "vertex-ai", "gcp-vertex", "vertexai"):
+            from agent.vertex_adapter import has_explicit_vertex_config
+
+            if has_explicit_vertex_config():
+                return True
+        elif normalized == "bedrock":
+            from hermes_cli.config import load_config as _load_cfg
+
+            bedrock_cfg = _load_cfg().get("bedrock")
+            if isinstance(bedrock_cfg, dict) and str(
+                bedrock_cfg.get("region") or ""
+            ).strip():
+                return True
+    except Exception:
+        pass
+
     return False
 
 
diff --git a/tests/hermes_cli/test_auth_provider_gate.py b/tests/hermes_cli/test_auth_provider_gate.py
index 94cb33a5cc..a3996876a2 100644
--- a/tests/hermes_cli/test_auth_provider_gate.py
+++ b/tests/hermes_cli/test_auth_provider_gate.py
@@ -52,6 +52,70 @@ def test_ambient_pool_source_does_not_count_as_explicit(tmp_path, monkeypatch):
     assert is_provider_explicitly_configured("copilot") is False
 
 
+def test_vertex_adc_counts_as_explicit_when_config_present(tmp_path, monkeypatch):
+    """A keyless Vertex provider is explicitly configured when the user pointed
+    Hermes at it (VERTEX_PROJECT_ID / vertex.project_id / VERTEX_CREDENTIALS_PATH),
+    even when it is NOT the current provider — otherwise it silently vanishes
+    from explicit-only pickers (desktop chat model menu) unless already selected."""
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes"))
+    for var in ("VERTEX_PROJECT_ID", "VERTEX_CREDENTIALS_PATH", "GOOGLE_APPLICATION_CREDENTIALS"):
+        monkeypatch.delenv(var, raising=False)
+    _write_auth_store(tmp_path, {"version": 1, "providers": {}, "active_provider": None})
+
+    from hermes_cli.auth import is_provider_explicitly_configured
+
+    # vertex.project_id in config.yaml is a deliberate, Hermes-scoped signal.
+    _write_config(tmp_path, {
+        "model": {"provider": "anthropic", "default": "claude-opus-4-8"},
+        "vertex": {"project_id": "my-gcp-project"},
+    })
+    assert is_provider_explicitly_configured("vertex") is True
+
+    # No Hermes-scoped Vertex config at all → stays hidden.
+    _write_config(tmp_path, {"model": {"provider": "anthropic", "default": "claude-opus-4-8"}})
+    assert is_provider_explicitly_configured("vertex") is False
+
+
+def test_vertex_ambient_google_creds_env_does_not_count_as_explicit(tmp_path, monkeypatch):
+    """An ambient GOOGLE_APPLICATION_CREDENTIALS path (commonly set globally for
+    unrelated GCP work) must NOT mark Vertex explicit — only Hermes-scoped
+    signals do. Regression guard for the picker gate (PR review feedback)."""
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes"))
+    monkeypatch.delenv("VERTEX_PROJECT_ID", raising=False)
+    monkeypatch.delenv("VERTEX_CREDENTIALS_PATH", raising=False)
+    _write_config(tmp_path, {"model": {"provider": "anthropic", "default": "claude-opus-4-8"}})
+    _write_auth_store(tmp_path, {"version": 1, "providers": {}, "active_provider": None})
+
+    # A real, existing SA file pointed to ONLY by the ambient Google var.
+    sa = tmp_path / "adc.json"
+    sa.write_text("{}")
+    monkeypatch.setenv("GOOGLE_APPLICATION_CREDENTIALS", str(sa))
+
+    from hermes_cli.auth import is_provider_explicitly_configured
+    assert is_provider_explicitly_configured("vertex") is False
+
+
+def test_bedrock_region_counts_as_explicit(tmp_path, monkeypatch):
+    """Bedrock (AWS SDK auth, no API key) is explicitly configured once the
+    user pins a region in config.yaml, mirroring the Vertex keyless case."""
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes"))
+    _write_auth_store(tmp_path, {"version": 1, "providers": {}, "active_provider": None})
+
+    from hermes_cli.auth import is_provider_explicitly_configured
+
+    _write_config(tmp_path, {
+        "model": {"provider": "anthropic", "default": "claude-opus-4-8"},
+        "bedrock": {"region": "us-east-1"},
+    })
+    assert is_provider_explicitly_configured("bedrock") is True
+
+    _write_config(tmp_path, {
+        "model": {"provider": "anthropic", "default": "claude-opus-4-8"},
+        "bedrock": {"region": ""},
+    })
+    assert is_provider_explicitly_configured("bedrock") is False
+
+
 def test_returns_true_when_moa_reference_slot_uses_provider(tmp_path, monkeypatch):
     """MoA advisor slots are explicit provider selections for auth gating."""
     monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes"))