diff --git a/CHANGELOG.md b/CHANGELOG.md
index fa8707a0..8236ccb2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,17 @@
 # Hermes Web UI -- Changelog
 
+## [v0.50.282] — 2026-05-03
+
+### Fixed (1 PR — closes #1538, #1539)
+
+- **Nous Portal full live catalog + dropdown cache invalidation on provider remove** (#1544; closes #1538, #1539) — two related dropdown-staleness bugs reported by Deor (Discord, May 03 2026, relayed by AvidFuturist). Same root shape: a model picker showing stale data because the live source of truth was never asked.
+
+  **#1538 — Nous Portal picker stuck at 4 hardcoded models.** `_PROVIDER_MODELS["nous"]` had four hardcoded entries (Claude Opus 4.6 / Sonnet 4.6, GPT-5.4 Mini, Gemini 3.1 Pro Preview) and `_build_available_models_uncached()` fell through to the generic `pid in _PROVIDER_MODELS` branch, deepcopying that four-entry list. The actual live Nous catalog has 30 models — Claude Opus 4.7, GPT-5.5, Kimi K2.6, MiniMax M2.7, Gemini 3.1 Pro/Flash, several Xiaomi/Tencent/StepFun entries, and more. Two parallel surfaces showed the stale four: `/api/models` (composer picker, Settings → Default Model, /model slash) and `/api/providers` (Settings → Providers card). **Fix:** new `_format_nous_label()` helper in `api/config.py` that drops the vendor namespace and appends ` (via Nous)` (reusing `_format_ollama_label`'s token rules); new `elif pid == "nous":` branch in `_build_available_models_uncached()` mirroring the Ollama Cloud pattern (live-fetch via `hermes_cli.models.provider_model_ids("nous")`, prefix every id with `@nous:` to match the existing routing convention pinned by `tests/test_nous_portal_routing.py`, fall back to the curated 4-entry static list when `hermes_cli` is unavailable so the picker is never empty); same fix applied to `api/providers.py:get_providers()` for the parallel card-list path.
+
+  **#1539 — Removed provider lingered in dropdowns until restart.** Server-side cache was correctly flushed (`set_provider_key()` calls `invalidate_models_cache()` on both add and remove), but three JS-side caches were never dropped after `/api/providers/delete`: `_slashModelCache`/`_slashModelCachePromise` (commands.js — feeds /model slash suggestions) and `_dynamicModelLabels`/`window._configuredModelBadges` (ui.js — populated by `populateModelDropdown`). Pre-fix, `_removeProviderKey()` only refreshed the providers card list and never asked any consumer to re-fetch /api/models. **Fix:** new `_invalidateSlashModelCache()` helper in `static/commands.js` (typeof-window-guarded so the module remains importable in headless `vm.runInContext` test contexts used by `tests/test_cli_only_slash_commands.py`); new `_refreshModelDropdownsAfterProviderChange()` helper in `static/panels.js` that calls the invalidator + `populateModelDropdown()`, wrapped in try/catch with a fire-and-forget `Promise.resolve(...).catch(()=>{})` so a slow `/api/models` doesn't block the providers panel refresh. Both `_saveProviderKey` and `_removeProviderKey` invoke the helper — defense-in-depth, the same staleness shape applies to the add path too.
+
+  Verified live on port 8789: `/api/models` Nous group returns 30 models (was 4); browser `document.getElementById('modelSelect')` exposes 30 options under "Nous Portal"; the dropdown-flush helpers are callable from the browser and round-trip rebuild keeps the dropdown at 30 options. nesquena APPROVED before merge with full end-to-end trace + behavioral harness on the label formatter; one non-blocking docstring observation (3-letter token rule produces "PRO" rather than "Pro" on tokens like `gemini-3.1-pro-preview`) addressed in a follow-up `docs:` commit on the same branch — pure docstring text, no behavioral change. 23 new regression tests (12 on `tests/test_issue1538_nous_live_catalog.py` covering live-fetch + @nous: prefix invariant + " (via Nous)" suffix invariant + recent-flagship coverage + static fallback when hermes_cli raises + label formatter unit tests + static-list preservation; 11 on `tests/test_issue1539_provider_removal_dropdown_invalidation.py` covering helper definition + both cache slots cleared + window exposure with typeof guard + both save and remove paths invoke flush + helper resilience to missing modules + helper does not block panel refresh + server-side `set_provider_key → invalidate_models_cache` invariant pinned). 4013 tests pass (was 3990 → 4013, +23 from this PR).
+
 ## [v0.50.281] — 2026-05-03
 
 ### Fixed (1 PR by external contributor — closes #1527, #1530)
diff --git a/ROADMAP.md b/ROADMAP.md
index e6037424..e3b862d6 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -2,7 +2,7 @@
 
 > Web companion to the Hermes Agent CLI. Same workflows, browser-native.
 >
-> Last updated: v0.50.281 (May 03, 2026) — 3995 tests collected
+> Last updated: v0.50.282 (May 03, 2026) — 4018 tests collected
 > Test source: `pytest tests/ --collect-only -q`
 > Per-version detail: see [CHANGELOG.md](./CHANGELOG.md)
 
diff --git a/TESTING.md b/TESTING.md
index 532502fa..37eaaabd 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -1835,8 +1835,8 @@ Bridged CLI sessions:
 
 ---
 
-*Last updated: v0.50.281, May 03, 2026*
-*Total automated tests collected: 3995*
+*Last updated: v0.50.282, May 03, 2026*
+*Total automated tests collected: 4018*
 *Regression gate: tests/test_regressions.py*
 *Run: pytest tests/ -v --timeout=60*
 *Source: <repo>/*
diff --git a/api/config.py b/api/config.py
index f6bd774f..694867b9 100644
--- a/api/config.py
+++ b/api/config.py
@@ -860,6 +860,37 @@ def _format_ollama_label(mid: str) -> str:
     return label
 
 
+def _format_nous_label(mid: str) -> str:
+    """Turn a Nous Portal model id into a readable display label.
+
+    Nous IDs are ``<vendor>/<model>[:<variant>]`` (e.g. ``anthropic/claude-opus-4.7``);
+    drop the vendor namespace, prettify the model name with the same token
+    rules as :func:`_format_ollama_label` (short acronyms uppercase, size
+    suffixes uppercase, capitalize the rest), then append ``" (via Nous)"``
+    so the entry is visually distinct from same-named models in other
+    provider groups (e.g. direct Anthropic).
+
+    Examples (matches the helper's actual output — labels are produced by
+    :func:`_format_ollama_label`'s token rules, so 3-letter tokens like
+    ``GPT`` and ``PRO`` render uppercase)::
+
+        anthropic/claude-opus-4.7         -> Claude Opus 4.7 (via Nous)
+        openai/gpt-5.4-mini               -> GPT 5.4 Mini (via Nous)
+        google/gemini-3.1-pro-preview     -> Gemini 3.1 PRO Preview (via Nous)
+        moonshotai/kimi-k2.6              -> Kimi K2.6 (via Nous)
+        qwen/qwen3.5-plus-02-15           -> Qwen3.5 Plus 02 15 (via Nous)
+        nvidia/nemotron-3-super-120b-a12b -> Nemotron 3 Super 120B A12b (via Nous)
+        minimax/minimax-m2.5:free         -> MiniMax M2.5 (Free) (via Nous)
+    """
+    name_part = mid.split("/", 1)[-1] if "/" in mid else mid
+    # MiniMax-CN ids come back lowercase on the live wire (`minimax-m2.5`) but
+    # the curated label convention is mixed-case "MiniMax M2.5" — match that.
+    if name_part.lower().startswith("minimax"):
+        name_part = "MiniMax" + name_part[len("minimax"):]
+    base = _format_ollama_label(name_part)
+    return f"{base} (via Nous)"
+
+
 def _apply_provider_prefix(
     raw_models: list[dict],
     provider_id: str,
@@ -2100,6 +2131,44 @@ def get_available_models() -> dict:
                     except Exception:
                         logger.warning("Failed to load Ollama Cloud models from hermes_cli")
 
+                    if raw_models:
+                        models = _apply_provider_prefix(raw_models, pid, active_provider)
+                        groups.append(
+                            {
+                                "provider": provider_name,
+                                "provider_id": pid,
+                                "models": models,
+                            }
+                        )
+                elif pid == "nous":
+                    # Nous Portal exposes a curated catalog (~30 models, currently)
+                    # via inference-api.nousresearch.com. Like ollama-cloud, we
+                    # live-fetch through hermes_cli.models.provider_model_ids()
+                    # rather than relying on the static four-entry list, which
+                    # chronically drifts out of date (#1538). Fall back to the
+                    # static list when hermes_cli is unavailable (test envs,
+                    # package mismatches) so the picker is never empty.
+                    raw_models = []
+                    try:
+                        from hermes_cli.models import provider_model_ids as _provider_model_ids
+
+                        live_ids = _provider_model_ids("nous") or []
+                        raw_models = [
+                            # Prefix every live id with "@nous:" so routing matches
+                            # the explicit-provider-hint branch of resolve_model_provider
+                            # (same convention as the curated static list — see
+                            # tests/test_nous_portal_routing.py for the invariant).
+                            {"id": f"@nous:{mid}", "label": _format_nous_label(mid)}
+                            for mid in live_ids
+                        ]
+                    except Exception:
+                        logger.warning("Failed to load Nous Portal models from hermes_cli")
+
+                    if not raw_models:
+                        # Static fallback: deepcopy so dedup/prefix mutation
+                        # below does not bleed into the module-level catalog.
+                        raw_models = copy.deepcopy(_PROVIDER_MODELS.get("nous", []))
+
                     if raw_models:
                         models = _apply_provider_prefix(raw_models, pid, active_provider)
                         groups.append(
diff --git a/api/providers.py b/api/providers.py
index 4226aa1f..74b41354 100644
--- a/api/providers.py
+++ b/api/providers.py
@@ -391,7 +391,26 @@ def get_providers() -> dict[str, Any]:
                 except Exception:
                     pass
 
-        models = _PROVIDER_MODELS.get(pid, [])
+        models = list(_PROVIDER_MODELS.get(pid, []))
+        # Nous Portal: prefer the live catalog so the providers card matches
+        # the dropdown picker (#1538). Same fallback shape as the static-only
+        # case below — when hermes_cli is unavailable or its lookup raises,
+        # we keep the four-entry curated list.
+        if pid == "nous":
+            try:
+                from hermes_cli.models import provider_model_ids as _provider_model_ids
+
+                live_ids = _provider_model_ids("nous") or []
+                if live_ids:
+                    # Lazy-import to avoid circular dep with api.config.
+                    from api.config import _format_nous_label
+
+                    models = [
+                        {"id": f"@nous:{mid}", "label": _format_nous_label(mid)}
+                        for mid in live_ids
+                    ]
+            except Exception:
+                logger.debug("Failed to load Nous Portal models from hermes_cli")
         # Also include models from config.yaml providers section
         if isinstance(providers_cfg, dict):
             provider_cfg = providers_cfg.get(pid, {})
diff --git a/static/commands.js b/static/commands.js
index dc806f19..375a9d67 100644
--- a/static/commands.js
+++ b/static/commands.js
@@ -88,6 +88,22 @@ let _slashPersonalityCachePromise=null;
 let _agentCommandCache=null;
 let _agentCommandCachePromise=null;
 
+// Invalidate the /api/models slash-suggestion cache. Called by panels.js
+// after a provider is added or removed so the next /model autocomplete
+// rebuilds from a fresh /api/models response (#1539). Returning a function
+// rather than letting callers poke the module-local lets/promises directly
+// keeps the cache shape encapsulated to this module.
+function _invalidateSlashModelCache(){
+  _slashModelCache=null;
+  _slashModelCachePromise=null;
+}
+// Expose on window when available. Guarded by typeof so the module is
+// importable in headless test contexts (vm.runInContext) that don't
+// define a window global — see tests/test_cli_only_slash_commands.py.
+if(typeof window!=='undefined'){
+  window._invalidateSlashModelCache=_invalidateSlashModelCache;
+}
+
 function _normalizeSlashSubArg(value){
   return String(value||'').trim();
 }
diff --git a/static/panels.js b/static/panels.js
index 5934a5c9..f633a7f4 100644
--- a/static/panels.js
+++ b/static/panels.js
@@ -3364,6 +3364,11 @@ async function _saveProviderKey(providerId){
     if(res.ok){
       showToast(res.provider+' key '+res.action);
       els.input.value='';
+      // Invalidate every dropdown surface that caches /api/models so the
+      // newly-configured provider's models show up without a server restart
+      // or page reload (#1539). Server-side invalidate_models_cache() is
+      // already called by api/providers.py:set_provider_key.
+      _refreshModelDropdownsAfterProviderChange();
       await loadProvidersPanel(); // refresh list
     }else{
       showToast(res.error||'Failed to save key');
@@ -3385,6 +3390,12 @@ async function _removeProviderKey(providerId){
     const res=await api('/api/providers/delete',{method:'POST',body:JSON.stringify({provider:providerId})});
     if(res.ok){
       showToast(res.provider+' key '+t('providers_key_removed').toLowerCase());
+      // Drop the removed provider from every cached dropdown surface so it
+      // disappears immediately — composer picker, /model slash command,
+      // Settings → Default Model, configured-model badges (#1539).
+      // Without this, a stale list from before the delete keeps offering
+      // the now-removed provider's models until the page is reloaded.
+      _refreshModelDropdownsAfterProviderChange();
       await loadProvidersPanel(); // refresh list
     }else{
       showToast(res.error||'Failed to remove key');
@@ -3396,6 +3407,28 @@ async function _removeProviderKey(providerId){
   }
 }
 
+// Shared dropdown-cache flush invoked after a provider add/remove. The
+// server-side TTL cache is already invalidated by /api/providers and
+// /api/providers/delete (via api/providers.py:set_provider_key); this
+// flushes the JS-side caches so the next render rebuilds from a fresh
+// /api/models response. Wrapped in a try/catch so a UI module that hasn't
+// loaded yet (e.g. during early Settings open) cannot break the save flow.
+function _refreshModelDropdownsAfterProviderChange(){
+  try{
+    if(typeof window._invalidateSlashModelCache==='function'){
+      window._invalidateSlashModelCache();
+    }
+    if(typeof populateModelDropdown==='function'){
+      // Fire-and-forget: don't block the providers panel refresh on a
+      // dropdown rebuild. The composer/Settings dropdowns will catch up
+      // on the very next paint frame.
+      Promise.resolve(populateModelDropdown()).catch(()=>{});
+    }
+  }catch(_e){
+    // Swallow — dropdown refresh is best-effort, providers panel must still update.
+  }
+}
+
 async function _refreshProviderModels(providerId, btn){
   btn.disabled=true;
   const orig=btn.innerHTML;
diff --git a/tests/test_issue1538_nous_live_catalog.py b/tests/test_issue1538_nous_live_catalog.py
new file mode 100644
index 00000000..4a9ddb03
--- /dev/null
+++ b/tests/test_issue1538_nous_live_catalog.py
@@ -0,0 +1,313 @@
+"""Regression tests for #1538 — Nous Portal model picker should live-fetch
+the full catalog (~30 models) instead of returning the four-entry static list.
+
+Background
+----------
+Settings → Default Model showed only four Nous models (Claude Opus 4.6, Claude
+Sonnet 4.6, GPT-5.4 Mini, Gemini 3.1 Pro Preview) because
+``_build_available_models_uncached()`` fell through to the generic
+``pid in _PROVIDER_MODELS`` branch and returned ``copy.deepcopy(_PROVIDER_MODELS["nous"])``.
+The actual Nous Portal catalog has ~30 models live — including the latest
+Anthropic 4.7 family, GPT-5.5, Gemini 3.1 Pro/Flash, Kimi K2.6, MiniMax M2.7,
+several Xiaomi/Tencent/StepFun entries.
+
+Fix
+---
+A dedicated ``elif pid == "nous":`` branch in ``_build_available_models_uncached()``
+mirroring the Ollama Cloud pattern: live-fetch via
+``hermes_cli.models.provider_model_ids("nous")``, prefix every id with ``@nous:``
+to match the existing routing convention, fall back to the curated static
+list when ``hermes_cli`` is unavailable.
+"""
+
+from __future__ import annotations
+
+import sys
+import types
+
+import api.config as config
+import api.profiles as profiles
+
+
+# Sample Nous catalog used in the live-fetch test. Mirrors the shape returned
+# by hermes_cli.models.provider_model_ids("nous") (see #1538 issue body).
+SAMPLE_NOUS_LIVE_IDS = [
+    "moonshotai/kimi-k2.6",
+    "xiaomi/mimo-v2.5-pro",
+    "anthropic/claude-opus-4.7",
+    "anthropic/claude-opus-4.6",
+    "anthropic/claude-sonnet-4.6",
+    "anthropic/claude-haiku-4.5",
+    "openai/gpt-5.5",
+    "openai/gpt-5.4-mini",
+    "openai/gpt-5.3-codex",
+    "google/gemini-3-pro-preview",
+    "google/gemini-3.1-pro-preview",
+    "google/gemini-3.1-flash-lite-preview",
+    "qwen/qwen3.5-plus-02-15",
+    "minimax/minimax-m2.7",
+    "z-ai/glm-5.1",
+    "x-ai/grok-4.20-beta",
+    "tencent/hy3-preview",
+    "stepfun/step-3.5-flash",
+    "nvidia/nemotron-3-super-120b-a12b",
+    "arcee-ai/trinity-large-thinking",
+]
+
+
+def _install_fake_hermes_cli(monkeypatch, *, nous_ids=None, raise_on_lookup=False):
+    """Install fake ``hermes_cli`` modules so detection sees Nous as authenticated
+    and ``provider_model_ids("nous")`` returns the desired catalog.
+
+    Mirrors :func:`tests.test_issue1420_lmstudio_provider_env_var._install_fake_hermes_cli`
+    but specialised for Nous detection (Nous is OAuth so the env-var path
+    is not used — we drive detection via ``hermes_cli.auth.list_auth_providers``).
+    """
+    fake_pkg = types.ModuleType("hermes_cli")
+    fake_pkg.__path__ = []
+
+    fake_models = types.ModuleType("hermes_cli.models")
+    fake_models.list_available_providers = lambda: []
+    if raise_on_lookup:
+        def _raise(_pid):
+            raise RuntimeError("simulated hermes_cli failure")
+        fake_models.provider_model_ids = _raise
+    else:
+        ids = list(nous_ids) if nous_ids is not None else []
+        fake_models.provider_model_ids = lambda pid: ids if pid == "nous" else []
+
+    fake_auth = types.ModuleType("hermes_cli.auth")
+
+    def _list_auth_providers():
+        return [{"id": "nous", "authenticated": True}]
+
+    def _get_auth_status(pid):
+        return {"logged_in": True, "key_source": ""} if pid == "nous" else {}
+
+    fake_auth.list_auth_providers = _list_auth_providers
+    fake_auth.get_auth_status = _get_auth_status
+
+    monkeypatch.setitem(sys.modules, "hermes_cli", fake_pkg)
+    monkeypatch.setitem(sys.modules, "hermes_cli.models", fake_models)
+    monkeypatch.setitem(sys.modules, "hermes_cli.auth", fake_auth)
+    monkeypatch.delitem(sys.modules, "agent.credential_pool", raising=False)
+    monkeypatch.delitem(sys.modules, "agent", raising=False)
+
+    config.invalidate_models_cache()
+
+
+def _swap_in_test_config(extra_cfg):
+    """Snapshot config.cfg, replace with a minimal test config; return restore-fn."""
+    old_cfg = dict(config.cfg)
+    old_mtime = config._cfg_mtime
+    config.cfg.clear()
+    config.cfg["model"] = {}
+    config.cfg.update(extra_cfg)
+    try:
+        config._cfg_mtime = config.Path(config._get_config_path()).stat().st_mtime
+    except Exception:
+        config._cfg_mtime = 0.0
+
+    def _restore():
+        config.cfg.clear()
+        config.cfg.update(old_cfg)
+        config._cfg_mtime = old_mtime
+
+    return _restore
+
+
+def _scrub_provider_env(monkeypatch):
+    """Drop every provider env var so detection only sees what we install
+    via the fake hermes_cli stubs (not unrelated keys leaked from the runner)."""
+    for var in (
+        "ANTHROPIC_API_KEY", "OPENAI_API_KEY", "GOOGLE_API_KEY", "GEMINI_API_KEY",
+        "DEEPSEEK_API_KEY", "XAI_API_KEY", "GROQ_API_KEY",
+        "MISTRAL_API_KEY", "OPENROUTER_API_KEY",
+        "OLLAMA_CLOUD_API_KEY", "OLLAMA_API_KEY",
+        "GLM_API_KEY", "KIMI_API_KEY", "MOONSHOT_API_KEY",
+        "MINIMAX_API_KEY", "MINIMAX_CN_API_KEY",
+        "OPENCODE_ZEN_API_KEY", "OPENCODE_GO_API_KEY",
+        "NOUS_API_KEY", "NVIDIA_API_KEY", "LM_API_KEY", "LMSTUDIO_API_KEY",
+    ):
+        monkeypatch.delenv(var, raising=False)
+
+
+class TestNousLiveCatalog:
+    """When the Nous live catalog is available, the dropdown must surface it
+    in full (>=20 entries) — not the four-entry static fallback (#1538)."""
+
+    def test_nous_models_live_fetch_when_hermes_cli_available(self, monkeypatch, tmp_path):
+        _scrub_provider_env(monkeypatch)
+        _install_fake_hermes_cli(monkeypatch, nous_ids=SAMPLE_NOUS_LIVE_IDS)
+        monkeypatch.setattr(profiles, "get_active_hermes_home", lambda: tmp_path)
+
+        restore = _swap_in_test_config({"model": {"provider": "nous"}})
+        try:
+            data = config.get_available_models()
+            nous_groups = [g for g in data.get("groups", []) if g.get("provider_id") == "nous"]
+            assert len(nous_groups) == 1, (
+                f"Expected exactly one Nous group, got {len(nous_groups)}: "
+                f"{[g.get('provider_id') for g in data.get('groups', [])]}"
+            )
+            models = nous_groups[0]["models"]
+            assert len(models) >= 20, (
+                f"Live-fetched Nous catalog should expose >=20 entries, got "
+                f"{len(models)}. The dispatch branch fell through to the four-entry "
+                f"static list — pre-#1538 behaviour."
+            )
+        finally:
+            restore()
+
+    def test_nous_model_ids_carry_at_nous_prefix(self, monkeypatch, tmp_path):
+        _scrub_provider_env(monkeypatch)
+        _install_fake_hermes_cli(monkeypatch, nous_ids=SAMPLE_NOUS_LIVE_IDS)
+        monkeypatch.setattr(profiles, "get_active_hermes_home", lambda: tmp_path)
+
+        restore = _swap_in_test_config({"model": {"provider": "nous"}})
+        try:
+            data = config.get_available_models()
+            nous_group = next(g for g in data["groups"] if g["provider_id"] == "nous")
+            for m in nous_group["models"]:
+                assert m["id"].startswith("@nous:"), (
+                    f"Every Nous model id must start with '@nous:' so "
+                    f"resolve_model_provider routes through the explicit-provider-hint "
+                    f"branch (matches the static-list invariant from "
+                    f"tests/test_nous_portal_routing.py). Got: {m['id']!r}"
+                )
+        finally:
+            restore()
+
+    def test_nous_labels_carry_via_nous_suffix(self, monkeypatch, tmp_path):
+        _scrub_provider_env(monkeypatch)
+        _install_fake_hermes_cli(monkeypatch, nous_ids=SAMPLE_NOUS_LIVE_IDS)
+        monkeypatch.setattr(profiles, "get_active_hermes_home", lambda: tmp_path)
+
+        restore = _swap_in_test_config({"model": {"provider": "nous"}})
+        try:
+            data = config.get_available_models()
+            nous_group = next(g for g in data["groups"] if g["provider_id"] == "nous")
+            for m in nous_group["models"]:
+                assert m["label"].endswith(" (via Nous)"), (
+                    f"Every Nous live-fetched label must end with ' (via Nous)' so "
+                    f"the user can distinguish them from same-named direct-provider "
+                    f"entries (e.g. 'Claude Opus 4.7' via direct Anthropic). "
+                    f"Got: {m['label']!r}"
+                )
+        finally:
+            restore()
+
+    def test_nous_live_catalog_includes_recent_models(self, monkeypatch, tmp_path):
+        """Sanity: the recent-flagship models from the user's bug report
+        (Claude Opus 4.7, GPT-5.5, Kimi K2.6) must reach the dropdown."""
+        _scrub_provider_env(monkeypatch)
+        _install_fake_hermes_cli(monkeypatch, nous_ids=SAMPLE_NOUS_LIVE_IDS)
+        monkeypatch.setattr(profiles, "get_active_hermes_home", lambda: tmp_path)
+
+        restore = _swap_in_test_config({"model": {"provider": "nous"}})
+        try:
+            data = config.get_available_models()
+            nous_group = next(g for g in data["groups"] if g["provider_id"] == "nous")
+            ids = {m["id"] for m in nous_group["models"]}
+            for required in (
+                "@nous:anthropic/claude-opus-4.7",
+                "@nous:openai/gpt-5.5",
+                "@nous:moonshotai/kimi-k2.6",
+                "@nous:google/gemini-3.1-pro-preview",
+                "@nous:minimax/minimax-m2.7",
+            ):
+                assert required in ids, (
+                    f"{required} missing from live-fetched Nous catalog. Either "
+                    f"the hermes_cli dispatch is broken or the @nous: prefix is "
+                    f"missing."
+                )
+        finally:
+            restore()
+
+
+class TestNousStaticFallback:
+    """When ``hermes_cli`` is not importable or its lookup raises, we fall back
+    to the curated four-entry static list — never empty."""
+
+    def test_static_fallback_when_hermes_cli_raises(self, monkeypatch, tmp_path):
+        _scrub_provider_env(monkeypatch)
+        _install_fake_hermes_cli(monkeypatch, raise_on_lookup=True)
+        monkeypatch.setattr(profiles, "get_active_hermes_home", lambda: tmp_path)
+
+        restore = _swap_in_test_config({"model": {"provider": "nous"}})
+        try:
+            data = config.get_available_models()
+            nous_groups = [g for g in data.get("groups", []) if g.get("provider_id") == "nous"]
+            assert nous_groups, (
+                "Nous group must still appear when hermes_cli fails — the "
+                "branch should fall back to the curated static list."
+            )
+            models = nous_groups[0]["models"]
+            assert len(models) == 4, (
+                f"Static fallback should expose exactly the four curated entries "
+                f"in _PROVIDER_MODELS['nous']. Got {len(models)}: "
+                f"{[m['id'] for m in models]}"
+            )
+            for m in models:
+                assert m["id"].startswith("@nous:"), m["id"]
+        finally:
+            restore()
+
+
+class TestFormatNousLabel:
+    """Unit tests for the label formatter helper."""
+
+    def test_strips_vendor_namespace(self):
+        from api.config import _format_nous_label
+        assert _format_nous_label("anthropic/claude-opus-4.7") == "Claude Opus 4.7 (via Nous)"
+        assert _format_nous_label("openai/gpt-5.4-mini") == "GPT 5.4 Mini (via Nous)"
+
+    def test_handles_missing_vendor(self):
+        from api.config import _format_nous_label
+        # Defensive: id without slash should still render a sane label.
+        assert _format_nous_label("kimi-k2.6") == "Kimi K2.6 (via Nous)"
+
+    def test_handles_variant_after_colon(self):
+        from api.config import _format_nous_label
+        # Variant rendered in parentheses, mirroring _format_ollama_label.
+        out = _format_nous_label("minimax/minimax-m2.5:free")
+        assert out.endswith(" (via Nous)")
+        assert "Free" in out
+        assert "MiniMax M2.5" in out
+
+    def test_minimax_renders_mixed_case(self):
+        from api.config import _format_nous_label
+        # Live wire returns lowercase 'minimax/minimax-...' but the curated
+        # convention is mixed-case 'MiniMax'.
+        assert _format_nous_label("minimax/minimax-m2.7").startswith("MiniMax M2.7")
+
+    def test_label_always_ends_with_via_nous_suffix(self):
+        from api.config import _format_nous_label
+        for sample in [
+            "anthropic/claude-opus-4.7",
+            "openai/gpt-5.5",
+            "google/gemini-3.1-pro-preview",
+            "moonshotai/kimi-k2.6",
+            "z-ai/glm-5.1",
+            "stepfun/step-3.5-flash",
+        ]:
+            assert _format_nous_label(sample).endswith(" (via Nous)"), sample
+
+
+class TestStaticListPreservedAsFallback:
+    """The curated ``_PROVIDER_MODELS['nous']`` entry stays as the static
+    fallback; existing routing invariants from
+    :mod:`tests.test_nous_portal_routing` must remain valid."""
+
+    def test_static_list_present(self):
+        from api.config import _PROVIDER_MODELS
+        assert _PROVIDER_MODELS.get("nous"), (
+            "The curated static Nous list must remain in _PROVIDER_MODELS as "
+            "a fallback for environments where hermes_cli is unavailable."
+        )
+
+    def test_static_list_keeps_at_nous_prefix(self):
+        # Keep parity with tests/test_nous_portal_routing.py — ensures the
+        # static fallback path produces correctly-routable ids when used.
+        from api.config import _PROVIDER_MODELS
+        for m in _PROVIDER_MODELS["nous"]:
+            assert m["id"].startswith("@nous:"), m["id"]
diff --git a/tests/test_issue1539_provider_removal_dropdown_invalidation.py b/tests/test_issue1539_provider_removal_dropdown_invalidation.py
new file mode 100644
index 00000000..59ada50d
--- /dev/null
+++ b/tests/test_issue1539_provider_removal_dropdown_invalidation.py
@@ -0,0 +1,225 @@
+"""Regression tests for #1539 — removing a provider in Settings must invalidate
+every dropdown surface that caches /api/models, so the removed provider
+disappears immediately without a server restart or page reload.
+
+The bug
+-------
+Pre-fix, ``_removeProviderKey()`` in ``static/panels.js`` only called
+``loadProvidersPanel()`` after deletion. That refreshed the providers card
+list but left these JS-side caches stale:
+
+  * ``_slashModelCache`` / ``_slashModelCachePromise`` (``static/commands.js``) —
+    cache for the ``/model`` slash-command suggestions.
+  * ``_dynamicModelLabels`` / ``window._configuredModelBadges`` (``static/ui.js``) —
+    populated by ``populateModelDropdown()`` on boot and on profile switch.
+
+Layered server-side cache via ``api/config.invalidate_models_cache`` was
+already flushed (``set_provider_key`` calls it on both add + remove), so the
+next ``/api/models`` request would return the correct list — but no consumer
+was triggering one.
+
+The fix
+-------
+``static/commands.js`` exposes an ``_invalidateSlashModelCache()`` helper on
+``window``. ``static/panels.js`` calls it from a shared
+``_refreshModelDropdownsAfterProviderChange()`` helper after both the save
+and the remove paths, plus invokes ``populateModelDropdown()`` to rebuild
+the composer / Settings dropdowns and ``_configuredModelBadges`` map.
+"""
+
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+import pytest
+
+
+REPO = Path(__file__).resolve().parent.parent
+
+
+def _read_static(name: str) -> str:
+    return (REPO / "static" / name).read_text(encoding="utf-8")
+
+
+def _extract_function_body(src: str, signature: str) -> str:
+    """Return the source of a top-level ``async function NAME(...)`` /
+    ``function NAME(...)`` declaration via brace-balance — robust to nested
+    blocks (try/catch/await) and not dependent on indentation.
+    """
+    idx = src.find(signature)
+    if idx == -1:
+        raise AssertionError(f"signature {signature!r} not found in source")
+    open_idx = src.find("{", idx)
+    if open_idx == -1:
+        raise AssertionError(f"could not find opening brace after {signature!r}")
+    depth = 0
+    for i in range(open_idx, len(src)):
+        c = src[i]
+        if c == "{":
+            depth += 1
+        elif c == "}":
+            depth -= 1
+            if depth == 0:
+                return src[idx : i + 1]
+    raise AssertionError(f"unbalanced braces in {signature!r}")
+
+
+class TestSlashModelCacheInvalidator:
+    """``static/commands.js`` must export the helper to ``window`` so
+    ``static/panels.js`` can drop the slash-command cache without poking
+    module-local lets across module boundaries."""
+
+    def test_invalidator_helper_defined(self):
+        src = _read_static("commands.js")
+        assert "function _invalidateSlashModelCache(" in src, (
+            "_invalidateSlashModelCache helper missing from static/commands.js. "
+            "Without it static/panels.js cannot drop the /model slash-command "
+            "cache when a provider is added/removed (#1539)."
+        )
+
+    def test_invalidator_clears_both_cache_slots(self):
+        src = _read_static("commands.js")
+        body = _extract_function_body(src, "function _invalidateSlashModelCache(")
+        # Cache slots from static/commands.js:84-85 — keep both null'd.
+        assert "_slashModelCache=null" in body, (
+            "_invalidateSlashModelCache must null _slashModelCache so the next "
+            "/model autocomplete refetches /api/models."
+        )
+        assert "_slashModelCachePromise=null" in body, (
+            "_invalidateSlashModelCache must null _slashModelCachePromise so an "
+            "in-flight load doesn't resolve into the stale cache slot after "
+            "invalidation."
+        )
+
+    def test_invalidator_exposed_on_window(self):
+        src = _read_static("commands.js")
+        # Exposed on window via a typeof-guarded assignment so the module is
+        # also importable in headless test contexts (vm.runInContext) that
+        # don't define a window global.
+        assert "window._invalidateSlashModelCache=_invalidateSlashModelCache" in src, (
+            "_invalidateSlashModelCache must be exposed on window so static/panels.js "
+            "can invoke it across module boundaries."
+        )
+        assert "typeof window!=='undefined'" in src, (
+            "The window-export assignment must be guarded by `typeof window!=='undefined'` "
+            "so static/commands.js stays importable in headless vm contexts (the "
+            "tests/test_cli_only_slash_commands.py harness has no window global)."
+        )
+
+
+class TestProviderRemoveInvalidatesDropdowns:
+    """The remove path in ``static/panels.js`` must trigger the dropdown-cache
+    flush and rebuild — otherwise the dropped provider lingers in every
+    /model dropdown until the page reloads (#1539)."""
+
+    def test_remove_path_invokes_dropdown_flush(self):
+        src = _read_static("panels.js")
+        body = _extract_function_body(src, "async function _removeProviderKey(")
+        assert "_refreshModelDropdownsAfterProviderChange()" in body, (
+            "_removeProviderKey must call _refreshModelDropdownsAfterProviderChange() "
+            "after a successful delete. Without this, the JS-side caches "
+            "(_slashModelCache, _dynamicModelLabels, _configuredModelBadges) "
+            "still offer the deleted provider's models until reload (#1539)."
+        )
+
+    def test_save_path_invokes_dropdown_flush(self):
+        """Defense-in-depth: adding a key has the same staleness shape — the
+        new provider's models won't show up until reload without this call.
+        Bundled in #1539."""
+        src = _read_static("panels.js")
+        body = _extract_function_body(src, "async function _saveProviderKey(")
+        assert "_refreshModelDropdownsAfterProviderChange()" in body, (
+            "_saveProviderKey must also call _refreshModelDropdownsAfterProviderChange() "
+            "so a newly-configured provider's models appear in every dropdown "
+            "without a reload. Same staleness shape as the remove path (#1539)."
+        )
+
+    def test_dropdown_flush_helper_defined(self):
+        src = _read_static("panels.js")
+        assert "function _refreshModelDropdownsAfterProviderChange(" in src, (
+            "_refreshModelDropdownsAfterProviderChange must be defined in "
+            "static/panels.js (single helper used by both save + remove paths)."
+        )
+
+    def test_dropdown_flush_calls_slash_cache_invalidator(self):
+        src = _read_static("panels.js")
+        body = _extract_function_body(src, "function _refreshModelDropdownsAfterProviderChange(")
+        # Must invoke the commands.js helper — directly poking module-local
+        # lets across module boundaries is brittle.
+        assert "_invalidateSlashModelCache" in body, (
+            "_refreshModelDropdownsAfterProviderChange must call "
+            "window._invalidateSlashModelCache() so the /model slash-command "
+            "cache is dropped (covers the slash-command surface from #1539)."
+        )
+
+    def test_dropdown_flush_calls_populate_model_dropdown(self):
+        src = _read_static("panels.js")
+        body = _extract_function_body(src, "function _refreshModelDropdownsAfterProviderChange(")
+        assert "populateModelDropdown" in body, (
+            "_refreshModelDropdownsAfterProviderChange must call "
+            "populateModelDropdown() so the composer model picker, Settings → "
+            "Default Model dropdown, _dynamicModelLabels, and "
+            "_configuredModelBadges all rebuild from a fresh /api/models "
+            "response (covers the dropdown + badge surfaces from #1539)."
+        )
+
+    def test_dropdown_flush_is_resilient_to_missing_modules(self):
+        """If commands.js or ui.js failed to load, the providers panel must
+        still update — the dropdown flush is best-effort (#1539)."""
+        src = _read_static("panels.js")
+        body = _extract_function_body(src, "function _refreshModelDropdownsAfterProviderChange(")
+        # Outer try/catch wraps the whole helper so a runtime error inside
+        # populateModelDropdown / cache flush cannot surface as an unhandled
+        # rejection that breaks the surrounding save/remove flow.
+        assert re.search(r"\btry\s*\{", body), (
+            "_refreshModelDropdownsAfterProviderChange must wrap its work in "
+            "try/catch — if commands.js or ui.js failed to load, a missing "
+            "function should not break the providers panel update (#1539)."
+        )
+        # And the populateModelDropdown call must be guarded by typeof — the
+        # dropdown rebuild is best-effort.
+        assert "typeof populateModelDropdown" in body, (
+            "populateModelDropdown lookup must use typeof so it gracefully "
+            "skips when ui.js hasn't loaded yet."
+        )
+
+    def test_dropdown_flush_does_not_block_panel_refresh(self):
+        """populateModelDropdown is async; its result must not be awaited
+        synchronously inside the helper — otherwise a slow /api/models would
+        delay the providers panel re-render (#1539)."""
+        src = _read_static("panels.js")
+        body = _extract_function_body(src, "function _refreshModelDropdownsAfterProviderChange(")
+        # The helper itself is non-async (signature checked indirectly: the
+        # source begins with 'function _refresh...', not 'async function').
+        # Anything async is fired with Promise.resolve(...).catch(...) so the
+        # provider panel re-render is not blocked.
+        assert body.startswith("function _refreshModelDropdownsAfterProviderChange"), (
+            "_refreshModelDropdownsAfterProviderChange should be a sync helper "
+            "that fires-and-forgets populateModelDropdown — not an async one "
+            "the save/remove paths await."
+        )
+
+
+class TestServerSideInvariantPreserved:
+    """Server-side ``invalidate_models_cache()`` is the load-bearing invariant
+    that lets the next /api/models request return correct data; #1539 was a
+    pure frontend bug, but pin the server-side wiring so a refactor of
+    ``set_provider_key`` cannot silently regress it."""
+
+    def test_set_provider_key_invalidates_cache(self):
+        src = (REPO / "api" / "providers.py").read_text(encoding="utf-8")
+        # set_provider_key is the canonical write path — both add and remove
+        # flow through it (remove_provider_key calls set_provider_key(pid, None)).
+        m = re.search(
+            r"def set_provider_key\([^)]*\).*?(?=\ndef |\Z)",
+            src,
+            re.DOTALL,
+        )
+        assert m, "set_provider_key not found in api/providers.py"
+        body = m.group(0)
+        assert "invalidate_models_cache()" in body, (
+            "set_provider_key must call invalidate_models_cache() so the "
+            "server-side TTL cache is flushed on every add/remove. Without "
+            "this, even a perfectly-cached frontend would receive stale data."
+        )