diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6115c51f..0c6a77dd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@
 
 ### Fixed
 
+- **PR #2135** by @franksong2702 — `/api/models/live?provider=custom:<slug>` now scopes custom-provider fallback models and direct `/v1/models` fetches to the requested named provider instead of leaking sibling `custom_providers` entries from the active profile. Bare `custom` only reads unnamed custom-provider entries, named custom providers also include `models` dict/list entries, and live fetch fallback uses the matched entry's `base_url` / `api_key` pair.
+
 - **PR #2117** by @ayushere — `ctl.sh start` no longer crashes on macOS (bash 3.2) with `preserved[@]: unbound variable`. The dotenv-preserve loop in `_load_repo_dotenv_preserving_env()` iterated `"${preserved[@]}"` under `set -euo pipefail`, which bash 4+ silently allows on empty arrays but bash 3.2 (still the default `/usr/bin/bash` on macOS) treats as an unbound-variable error. Guards the iteration with `if [[ ${#preserved[@]} -gt 0 ]]; then ... fi` — matches the canonical bash 3.2 strict-mode pattern. This is the third bash 3.2 compat fix to land in `ctl.sh` (prior: `025f137f` guarded `CTL_BOOTSTRAP_ARGS[@]` with the `${arr[@]+...}` pass-through pattern, `630981a0` replaced `[[ -v ${key} ]]` with `[[ -n "${!key+x}" ]]`). Defense-in-depth: added `tests/test_ctl_bash32_compat.py` (5 static-pattern regressions) pinning both empty-array guards plus a denylist for bash 4+ syntax (`declare -A`, `mapfile`, `[[ -v ]]`, `${var^^}`, `${var,,}`) so the next regression surfaces in CI instead of a macOS user's terminal. Stage-343 reviewer added the regression-test file alongside the contributor's 5-LOC fix to ctl.sh.
 
 ## [v0.51.49] — 2026-05-12 — Release Y (stage-342 — 3-PR contributor batch — read-only worktree status endpoint + worktree-retained response preference + Codex quota credential-pool fallback)
diff --git a/api/routes.py b/api/routes.py
index efae299c..49442eca 100644
--- a/api/routes.py
+++ b/api/routes.py
@@ -6104,27 +6104,85 @@ def _handle_live_models(handler, parsed):
             ids = []
 
         if not ids:
+            custom_provider_entry = None
+
+            def _custom_provider_entries_for_request():
+                if not (provider == "custom" or provider.startswith("custom:")):
+                    return []
+                try:
+                    from api.config import _custom_provider_slug_from_name
+                    _cp_entries = cfg.get("custom_providers", [])
+                    if not isinstance(_cp_entries, list):
+                        return []
+                    _matches = []
+                    for _cp in _cp_entries:
+                        if not isinstance(_cp, dict):
+                            continue
+                        _slug = _custom_provider_slug_from_name(_cp.get("name", ""))
+                        if provider.startswith("custom:"):
+                            if _slug == provider:
+                                _matches.append(_cp)
+                        elif provider == "custom" and not _slug:
+                            _matches.append(_cp)
+                    return _matches
+                except Exception:
+                    return []
+
+            def _custom_provider_model_ids(_cp):
+                _ids = []
+
+                def _append(_mid):
+                    _mid = str(_mid or "").strip()
+                    if _mid and _mid not in _ids:
+                        _ids.append(_mid)
+
+                _append(_cp.get("model", ""))
+                _models = _cp.get("models")
+                if isinstance(_models, dict):
+                    for _mid in _models:
+                        if isinstance(_mid, str):
+                            _append(_mid)
+                elif isinstance(_models, list):
+                    for _item in _models:
+                        if isinstance(_item, str):
+                            _append(_item)
+                        elif isinstance(_item, dict):
+                            _append(_item.get("id") or _item.get("model") or _item.get("name"))
+                return _ids
+
+            def _custom_provider_api_key(_cp):
+                _raw = _cp.get("api_key")
+                if _raw is not None:
+                    _key = str(_raw).strip()
+                    if _key.startswith("${") and _key.endswith("}") and len(_key) > 3:
+                        _key = os.getenv(_key[2:-1], "").strip()
+                    if _key:
+                        return _key
+                _env = str(_cp.get("key_env") or "").strip()
+                return os.getenv(_env, "").strip() if _env else ""
+
             # For 'custom' and 'custom:*' providers, provider_model_ids()
             # returns [] because they aren't real hermes_cli endpoints.
             # Fall back to the custom_providers entries from config.yaml so
             # the live-model enrichment step can add any models that weren't
             # already in the static list (issue #1619).
             if provider == "custom" or provider.startswith("custom:"):
-                try:
-                    _cp_entries = cfg.get("custom_providers", [])
-                    if isinstance(_cp_entries, list):
-                        ids = [
-                            _cp.get("model", "")
-                            for _cp in _cp_entries
-                            if isinstance(_cp, dict) and _cp.get("model", "")
-                        ]
-                except Exception:
-                    pass
+                for _cp in _custom_provider_entries_for_request():
+                    if custom_provider_entry is None:
+                        custom_provider_entry = _cp
+                    ids.extend(_custom_provider_model_ids(_cp))
             
             # If still no ids, try fetching from base_url directly (OpenAI-compat endpoint)
             if not ids and (provider == "custom" or provider.startswith("custom:")):
-                _base_url = cfg.get("model", {}).get("base_url")
-                _api_key = cfg.get("model", {}).get("api_key")
+                _base_url = None
+                _api_key = None
+                if custom_provider_entry:
+                    _base_url = custom_provider_entry.get("base_url")
+                    _api_key = _custom_provider_api_key(custom_provider_entry)
+                else:
+                    _model_cfg = cfg.get("model", {})
+                    _base_url = _model_cfg.get("base_url")
+                    _api_key = _model_cfg.get("api_key")
                 if _base_url and _api_key:
                     try:
                         import urllib.request
diff --git a/tests/test_byok_model_dropdown.py b/tests/test_byok_model_dropdown.py
index 181d68f4..835d17c8 100644
--- a/tests/test_byok_model_dropdown.py
+++ b/tests/test_byok_model_dropdown.py
@@ -177,6 +177,32 @@ class TestLiveModelsCustomProviderFallback:
     """When provider='custom' and provider_model_ids() returns [],
     /api/models/live must fall back to custom_providers entries from config.yaml."""
 
+    @staticmethod
+    def _install_provider_model_ids(monkeypatch, fn):
+        import types
+
+        hermes_cli = types.ModuleType("hermes_cli")
+        hermes_cli.__path__ = []
+        models = types.ModuleType("hermes_cli.models")
+        models.provider_model_ids = fn
+        monkeypatch.setitem(sys.modules, "hermes_cli", hermes_cli)
+        monkeypatch.setitem(sys.modules, "hermes_cli.models", models)
+
+    @staticmethod
+    def _call_live_models(monkeypatch, cfg, provider):
+        import api.config as c
+        import api.routes as r
+
+        r._clear_live_models_cache()
+        monkeypatch.setattr(c, "get_config", lambda: cfg)
+        monkeypatch.setattr(c, "_resolve_provider_alias", lambda p: p)
+        monkeypatch.setattr(r, "j", lambda _handler, payload, **_kw: payload)
+        TestLiveModelsCustomProviderFallback._install_provider_model_ids(monkeypatch, lambda _p: [])
+
+        parsed = mock.MagicMock()
+        parsed.query = f"provider={provider}"
+        return r._handle_live_models(object(), parsed)
+
     def test_custom_fallback_code_present(self):
         src = read("api/routes.py")
         m = re.search(
@@ -241,6 +267,110 @@ class TestLiveModelsCustomProviderFallback:
             f"got {model_ids}"
         )
 
+    def test_named_custom_fallback_returns_only_matching_provider_models(self, monkeypatch):
+        """custom:<slug> must not leak sibling custom_providers models."""
+        cfg = {
+            "model": {"provider": "custom:infini-ai"},
+            "custom_providers": [
+                {
+                    "name": "rightcode-codex",
+                    "model": "gpt-5.5",
+                    "models": {"gpt-5.5-mini": {}},
+                    "base_url": "https://right.codes/codex/v1",
+                },
+                {
+                    "name": "infini-ai",
+                    "model": "glm-5.1",
+                    "base_url": "https://open.bigmodel.cn/api/paas/v4",
+                },
+                {
+                    "name": "xiaomi-mimo",
+                    "models": ["mimo-v2.5-pro"],
+                    "base_url": "https://mimo.example.com/v1",
+                },
+            ],
+        }
+
+        resp = self._call_live_models(monkeypatch, cfg, "custom:rightcode-codex")
+
+        assert resp["provider"] == "custom:rightcode-codex"
+        assert [m["id"] for m in resp["models"]] == ["gpt-5.5", "gpt-5.5-mini"]
+
+    def test_bare_custom_fallback_ignores_named_custom_provider_models(self, monkeypatch):
+        """Bare custom only represents unnamed custom entries, not named siblings."""
+        cfg = {
+            "model": {"provider": "custom"},
+            "custom_providers": [
+                {"name": "rightcode-codex", "model": "gpt-5.5"},
+                {"name": "infini-ai", "model": "glm-5.1"},
+                {"model": "unnamed-byok-model"},
+            ],
+        }
+
+        resp = self._call_live_models(monkeypatch, cfg, "custom")
+
+        assert resp["provider"] == "custom"
+        assert [m["id"] for m in resp["models"]] == ["unnamed-byok-model"]
+
+    def test_named_custom_live_fetch_uses_matching_entry_endpoint(self, monkeypatch):
+        """custom:<slug> live fetch must use that entry, not the active model config."""
+        import json
+        import urllib.request
+
+        requests = []
+
+        class Response:
+            def __enter__(self):
+                return self
+
+            def __exit__(self, exc_type, exc, tb):
+                return False
+
+            def read(self):
+                return json.dumps({"data": [{"id": "right-live-model"}]}).encode("utf-8")
+
+        def fake_urlopen(req, timeout=None):
+            requests.append(
+                {
+                    "url": req.full_url,
+                    "authorization": req.headers.get("Authorization"),
+                    "timeout": timeout,
+                }
+            )
+            return Response()
+
+        cfg = {
+            "model": {
+                "provider": "custom:infini-ai",
+                "base_url": "https://infini.example.com/v1",
+                "api_key": "infini-key",
+            },
+            "custom_providers": [
+                {
+                    "name": "rightcode-codex",
+                    "base_url": "https://right.codes/codex/v1",
+                    "api_key": "right-key",
+                },
+                {
+                    "name": "infini-ai",
+                    "base_url": "https://infini.example.com/v1",
+                    "api_key": "infini-key",
+                },
+            ],
+        }
+        monkeypatch.setattr(urllib.request, "urlopen", fake_urlopen)
+
+        resp = self._call_live_models(monkeypatch, cfg, "custom:rightcode-codex")
+
+        assert requests == [
+            {
+                "url": "https://right.codes/codex/v1/models",
+                "authorization": "Bearer right-key",
+                "timeout": 8,
+            }
+        ]
+        assert [m["id"] for m in resp["models"]] == ["right-live-model"]
+
 
 # ── Regression: known-good providers still work ───────────────────────────────