feat: support multiple named custom providers in hermes model

Users with multiple local servers or custom endpoints can now define
them all in config.yaml and switch between them from the model
selection menu:

  custom_providers:
    - name: 'Local Llama 70B'
      base_url: 'http://localhost:8000/v1'
      api_key: 'not-needed'
    - name: 'RunPod vLLM'
      base_url: 'https://xyz.runpod.ai/v1'
      api_key: 'rp_xxxxx'

These appear in `hermes model` provider selection alongside the
built-in providers. When selected, the endpoint's /models API is
probed to show available models in a selection menu.

Previously only a single 'Custom endpoint' option existed, requiring
manual URL entry each time you wanted to switch between local servers.

Requested by @ZiarnoBobu on Twitter.

hermes_cli/main.py

@@ -761,9 +761,32 @@ def cmd_model(args):
         ("kimi-coding", "Kimi / Moonshot (Moonshot AI direct API)"),
         ("minimax", "MiniMax (global direct API)"),
         ("minimax-cn", "MiniMax China (domestic direct API)"),
-        ("custom", "Custom endpoint (self-hosted / VLLM / etc.)"),
     ]
 
+    # Add user-defined custom providers from config.yaml
+    custom_providers_cfg = config.get("custom_providers") or []
+    _custom_provider_map = {}  # key → {name, base_url, api_key}
+    if isinstance(custom_providers_cfg, list):
+        for entry in custom_providers_cfg:
+            if not isinstance(entry, dict):
+                continue
+            name = entry.get("name", "").strip()
+            base_url = entry.get("base_url", "").strip()
+            if not name or not base_url:
+                continue
+            # Generate a stable key from the name
+            key = "custom:" + name.lower().replace(" ", "-")
+            short_url = base_url.replace("https://", "").replace("http://", "").rstrip("/")
+            providers.append((key, f"{name} ({short_url})"))
+            _custom_provider_map[key] = {
+                "name": name,
+                "base_url": base_url,
+                "api_key": entry.get("api_key", ""),
+            }
+
+    # Always add the manual custom endpoint option last
+    providers.append(("custom", "Custom endpoint (enter URL manually)"))
+
     # Reorder so the active provider is at the top
     known_keys = {k for k, _ in providers}
     active_key = active if active in known_keys else "custom"
@@ -791,6 +814,8 @@ def cmd_model(args):
         _model_flow_openai_codex(config, current_model)
     elif selected_provider == "custom":
         _model_flow_custom(config)
+    elif selected_provider.startswith("custom:") and selected_provider in _custom_provider_map:
+        _model_flow_named_custom(config, _custom_provider_map[selected_provider])
     elif selected_provider in ("zai", "kimi-coding", "minimax", "minimax-cn"):
         _model_flow_api_key_provider(config, selected_provider, current_model)
 
@@ -1062,6 +1087,92 @@ def _model_flow_custom(config):
         print("Endpoint saved. Use `/model` in chat or `hermes model` to set a model.")
 
 
+def _model_flow_named_custom(config, provider_info):
+    """Handle a named custom provider from config.yaml custom_providers list."""
+    from hermes_cli.auth import _save_model_choice, deactivate_provider
+    from hermes_cli.config import save_env_value, load_config, save_config
+    from hermes_cli.models import fetch_api_models
+
+    name = provider_info["name"]
+    base_url = provider_info["base_url"]
+    api_key = provider_info.get("api_key", "")
+
+    print(f"  Provider: {name}")
+    print(f"  URL:      {base_url}")
+    print()
+
+    # Try to fetch available models from the endpoint
+    print("Fetching available models...")
+    models = fetch_api_models(api_key, base_url, timeout=8.0)
+
+    if models:
+        print(f"Found {len(models)} model(s):\n")
+        # Show model selection menu
+        try:
+            from simple_term_menu import TerminalMenu
+            menu_items = [f"  {m}" for m in models] + ["  Cancel"]
+            menu = TerminalMenu(
+                menu_items, cursor_index=0,
+                menu_cursor="-> ", menu_cursor_style=("fg_green", "bold"),
+                menu_highlight_style=("fg_green",),
+                cycle_cursor=True, clear_screen=False,
+                title=f"Select model from {name}:",
+            )
+            idx = menu.show()
+            print()
+            if idx is None or idx >= len(models):
+                print("Cancelled.")
+                return
+            model_name = models[idx]
+        except (ImportError, NotImplementedError):
+            # Fallback: numbered list
+            for i, m in enumerate(models, 1):
+                print(f"  {i}. {m}")
+            print(f"  {len(models) + 1}. Cancel")
+            print()
+            try:
+                val = input(f"Choice [1-{len(models) + 1}]: ").strip()
+                if not val:
+                    print("Cancelled.")
+                    return
+                idx = int(val) - 1
+                if idx < 0 or idx >= len(models):
+                    print("Cancelled.")
+                    return
+                model_name = models[idx]
+            except (ValueError, KeyboardInterrupt, EOFError):
+                print("\nCancelled.")
+                return
+    else:
+        print("Could not fetch models from endpoint. Enter model name manually.")
+        try:
+            model_name = input("Model name: ").strip()
+        except (KeyboardInterrupt, EOFError):
+            print("\nCancelled.")
+            return
+        if not model_name:
+            print("No model specified. Cancelled.")
+            return
+
+    # Save the endpoint + model
+    save_env_value("OPENAI_BASE_URL", base_url)
+    if api_key:
+        save_env_value("OPENAI_API_KEY", api_key)
+    _save_model_choice(model_name)
+
+    # Update config
+    cfg = load_config()
+    model = cfg.get("model")
+    if isinstance(model, dict):
+        model["provider"] = "custom"
+        model["base_url"] = base_url
+    save_config(cfg)
+    deactivate_provider()
+
+    print(f"\n✅ Model set to: {model_name}")
+    print(f"   Provider: {name} ({base_url})")
+
+
 # Curated model lists for direct API-key providers
 _PROVIDER_MODELS = {
     "zai": [