fix(custom-endpoint): verify /models and suggest working /v1 base URL

hermes_cli/main.py

@@ -1112,8 +1112,32 @@ def _model_flow_custom(config):
 
     effective_key = api_key or current_key
 
+    from hermes_cli.models import probe_api_models
+
+    probe = probe_api_models(effective_key, effective_url)
+    if probe.get("used_fallback") and probe.get("resolved_base_url"):
+        print(
+            f"Warning: endpoint verification worked at {probe['resolved_base_url']}/models, "
+            f"not the exact URL you entered. Saving the working base URL instead."
+        )
+        effective_url = probe["resolved_base_url"]
+        if base_url:
+            base_url = effective_url
+    elif probe.get("models") is not None:
+        print(
+            f"Verified endpoint via {probe.get('probed_url')} "
+            f"({len(probe.get('models') or [])} model(s) visible)"
+        )
+    else:
+        print(
+            f"Warning: could not verify this endpoint via {probe.get('probed_url')}. "
+            f"Hermes will still save it."
+        )
+        if probe.get("suggested_base_url"):
+            print(f"  If this server expects /v1, try base URL: {probe['suggested_base_url']}")
+
     if base_url:
-        save_env_value("OPENAI_BASE_URL", base_url)
+        save_env_value("OPENAI_BASE_URL", effective_url)
     if api_key:
         save_env_value("OPENAI_API_KEY", api_key)
 

hermes_cli/models.py

@@ -308,6 +308,62 @@ def _fetch_anthropic_models(timeout: float = 5.0) -> Optional[list[str]]:
         return None
 
 
+def probe_api_models(
+    api_key: Optional[str],
+    base_url: Optional[str],
+    timeout: float = 5.0,
+) -> dict[str, Any]:
+    """Probe an OpenAI-compatible ``/models`` endpoint with light URL heuristics."""
+    normalized = (base_url or "").strip().rstrip("/")
+    if not normalized:
+        return {
+            "models": None,
+            "probed_url": None,
+            "resolved_base_url": "",
+            "suggested_base_url": None,
+            "used_fallback": False,
+        }
+
+    if normalized.endswith("/v1"):
+        alternate_base = normalized[:-3].rstrip("/")
+    else:
+        alternate_base = normalized + "/v1"
+
+    candidates: list[tuple[str, bool]] = [(normalized, False)]
+    if alternate_base and alternate_base != normalized:
+        candidates.append((alternate_base, True))
+
+    tried: list[str] = []
+    headers: dict[str, str] = {}
+    if api_key:
+        headers["Authorization"] = f"Bearer {api_key}"
+
+    for candidate_base, is_fallback in candidates:
+        url = candidate_base.rstrip("/") + "/models"
+        tried.append(url)
+        req = urllib.request.Request(url, headers=headers)
+        try:
+            with urllib.request.urlopen(req, timeout=timeout) as resp:
+                data = json.loads(resp.read().decode())
+                return {
+                    "models": [m.get("id", "") for m in data.get("data", [])],
+                    "probed_url": url,
+                    "resolved_base_url": candidate_base.rstrip("/"),
+                    "suggested_base_url": alternate_base if alternate_base != candidate_base else normalized,
+                    "used_fallback": is_fallback,
+                }
+        except Exception:
+            continue
+
+    return {
+        "models": None,
+        "probed_url": tried[-1] if tried else normalized.rstrip("/") + "/models",
+        "resolved_base_url": normalized,
+        "suggested_base_url": alternate_base if alternate_base != normalized else None,
+        "used_fallback": False,
+    }
+
+
 def fetch_api_models(
     api_key: Optional[str],
     base_url: Optional[str],
@@ -318,22 +374,7 @@ def fetch_api_models(
     Returns a list of model ID strings, or ``None`` if the endpoint could not
     be reached (network error, timeout, auth failure, etc.).
     """
-    if not base_url:
+    return probe_api_models(api_key, base_url, timeout=timeout).get("models")
-        return None
-
-    url = base_url.rstrip("/") + "/models"
-    headers: dict[str, str] = {}
-    if api_key:
-        headers["Authorization"] = f"Bearer {api_key}"
-
-    req = urllib.request.Request(url, headers=headers)
-    try:
-        with urllib.request.urlopen(req, timeout=timeout) as resp:
-            data = json.loads(resp.read().decode())
-            # Standard OpenAI format: {"data": [{"id": "model-name", ...}, ...]}
-            return [m.get("id", "") for m in data.get("data", [])]
-    except Exception:
-        return None
 
 
 def validate_requested_model(
@@ -376,13 +417,53 @@ def validate_requested_model(
             "message": "Model names cannot contain spaces.",
         }
 
-    # Custom endpoints can serve any model — skip validation
     if normalized == "custom":
+        probe = probe_api_models(api_key, base_url)
+        api_models = probe.get("models")
+        if api_models is not None:
+            if requested in set(api_models):
+                return {
+                    "accepted": True,
+                    "persist": True,
+                    "recognized": True,
+                    "message": None,
+                }
+
+            suggestions = get_close_matches(requested, api_models, n=3, cutoff=0.5)
+            suggestion_text = ""
+            if suggestions:
+                suggestion_text = "\n  Similar models: " + ", ".join(f"`{s}`" for s in suggestions)
+
+            message = (
+                f"Note: `{requested}` was not found in this custom endpoint's model listing "
+                f"({probe.get('probed_url')}). It may still work if the server supports hidden or aliased models."
+                f"{suggestion_text}"
+            )
+            if probe.get("used_fallback"):
+                message += (
+                    f"\n  Endpoint verification succeeded after trying `{probe.get('resolved_base_url')}`. "
+                    f"Consider saving that as your base URL."
+                )
+
+            return {
+                "accepted": True,
+                "persist": True,
+                "recognized": False,
+                "message": message,
+            }
+
+        message = (
+            f"Note: could not reach this custom endpoint's model listing at `{probe.get('probed_url')}`. "
+            f"Hermes will still save `{requested}`, but the endpoint should expose `/models` for verification."
+        )
+        if probe.get("suggested_base_url"):
+            message += f"\n  If this server expects `/v1`, try base URL: `{probe.get('suggested_base_url')}`"
+
         return {
             "accepted": True,
             "persist": True,
             "recognized": False,
-            "message": None,
+            "message": message,
         }
 
     # Probe the live API to check if the model actually exists

hermes_cli/setup.py

@@ -933,11 +933,35 @@ def setup_model_provider(config: dict):
 
         base_url = prompt(
             "  API base URL (e.g., https://api.example.com/v1)", current_url
-        )
+        ).strip()
         api_key = prompt("  API key", password=True)
         model_name = prompt("  Model name (e.g., gpt-4, claude-3-opus)", current_model)
 
         if base_url:
+            from hermes_cli.models import probe_api_models
+
+            probe = probe_api_models(api_key, base_url)
+            if probe.get("used_fallback") and probe.get("resolved_base_url"):
+                print_warning(
+                    f"Endpoint verification worked at {probe['resolved_base_url']}/models, "
+                    f"not the exact URL you entered. Saving the working base URL instead."
+                )
+                base_url = probe["resolved_base_url"]
+            elif probe.get("models") is not None:
+                print_success(
+                    f"Verified endpoint via {probe.get('probed_url')} "
+                    f"({len(probe.get('models') or [])} model(s) visible)"
+                )
+            else:
+                print_warning(
+                    f"Could not verify this endpoint via {probe.get('probed_url')}. "
+                    f"Hermes will still save it."
+                )
+                if probe.get("suggested_base_url"):
+                    print_info(
+                        f"  If this server expects /v1, try base URL: {probe['suggested_base_url']}"
+                    )
+
             save_env_value("OPENAI_BASE_URL", base_url)
         if api_key:
             save_env_value("OPENAI_API_KEY", api_key)

tests/hermes_cli/test_model_validation.py

@@ -7,6 +7,7 @@ from hermes_cli.models import (
     fetch_api_models,
     normalize_provider,
     parse_model_input,
+    probe_api_models,
     provider_label,
     provider_model_ids,
     validate_requested_model,
@@ -26,7 +27,15 @@ FAKE_API_MODELS = [
 
 def _validate(model, provider="openrouter", api_models=FAKE_API_MODELS, **kw):
     """Shortcut: call validate_requested_model with mocked API."""
-    with patch("hermes_cli.models.fetch_api_models", return_value=api_models):
+    probe_payload = {
+        "models": api_models,
+        "probed_url": "http://localhost:11434/v1/models",
+        "resolved_base_url": kw.get("base_url", "") or "http://localhost:11434/v1",
+        "suggested_base_url": None,
+        "used_fallback": False,
+    }
+    with patch("hermes_cli.models.fetch_api_models", return_value=api_models), \
+         patch("hermes_cli.models.probe_api_models", return_value=probe_payload):
         return validate_requested_model(model, provider, **kw)
 
 
@@ -147,6 +156,33 @@ class TestFetchApiModels:
         with patch("hermes_cli.models.urllib.request.urlopen", side_effect=Exception("timeout")):
             assert fetch_api_models("key", "https://example.com/v1") is None
 
+    def test_probe_api_models_tries_v1_fallback(self):
+        class _Resp:
+            def __enter__(self):
+                return self
+
+            def __exit__(self, exc_type, exc, tb):
+                return False
+
+            def read(self):
+                return b'{"data": [{"id": "local-model"}]}'
+
+        calls = []
+
+        def _fake_urlopen(req, timeout=5.0):
+            calls.append(req.full_url)
+            if req.full_url.endswith("/v1/models"):
+                return _Resp()
+            raise Exception("404")
+
+        with patch("hermes_cli.models.urllib.request.urlopen", side_effect=_fake_urlopen):
+            probe = probe_api_models("key", "http://localhost:8000")
+
+        assert calls == ["http://localhost:8000/models", "http://localhost:8000/v1/models"]
+        assert probe["models"] == ["local-model"]
+        assert probe["resolved_base_url"] == "http://localhost:8000/v1"
+        assert probe["used_fallback"] is True
+
 
 # -- validate — format checks -----------------------------------------------
 
@@ -191,6 +227,7 @@ class TestValidateApiFound:
         )
         assert result["accepted"] is True
         assert result["persist"] is True
+        assert result["recognized"] is True
 
 
 # -- validate — API not found ------------------------------------------------
@@ -232,3 +269,26 @@ class TestValidateApiFallback:
         result = _validate("some-model", provider="totally-unknown", api_models=None)
         assert result["accepted"] is True
         assert result["persist"] is True
+
+    def test_custom_endpoint_warns_with_probed_url_and_v1_hint(self):
+        with patch(
+            "hermes_cli.models.probe_api_models",
+            return_value={
+                "models": None,
+                "probed_url": "http://localhost:8000/v1/models",
+                "resolved_base_url": "http://localhost:8000",
+                "suggested_base_url": "http://localhost:8000/v1",
+                "used_fallback": False,
+            },
+        ):
+            result = validate_requested_model(
+                "qwen3",
+                "custom",
+                api_key="local-key",
+                base_url="http://localhost:8000",
+            )
+
+        assert result["accepted"] is True
+        assert result["persist"] is True
+        assert "http://localhost:8000/v1/models" in result["message"]
+        assert "http://localhost:8000/v1" in result["message"]

tests/hermes_cli/test_setup_model_provider.py

@@ -75,6 +75,58 @@ def test_setup_keep_current_custom_from_config_does_not_fall_through(tmp_path, m
     assert calls["count"] == 1
 
 
+def test_setup_custom_endpoint_saves_working_v1_base_url(tmp_path, monkeypatch):
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    _clear_provider_env(monkeypatch)
+
+    config = load_config()
+
+    def fake_prompt_choice(question, choices, default=0):
+        if question == "Select your inference provider:":
+            return 3  # Custom endpoint
+        if question == "Configure vision:":
+            return len(choices) - 1  # Skip
+        raise AssertionError(f"Unexpected prompt_choice call: {question}")
+
+    def fake_prompt(message, current=None, **kwargs):
+        if "API base URL" in message:
+            return "http://localhost:8000"
+        if "API key" in message:
+            return "local-key"
+        if "Model name" in message:
+            return "llm"
+        return ""
+
+    monkeypatch.setattr("hermes_cli.setup.prompt_choice", fake_prompt_choice)
+    monkeypatch.setattr("hermes_cli.setup.prompt", fake_prompt)
+    monkeypatch.setattr("hermes_cli.setup.prompt_yes_no", lambda *args, **kwargs: False)
+    monkeypatch.setattr("hermes_cli.auth.get_active_provider", lambda: None)
+    monkeypatch.setattr("hermes_cli.auth.detect_external_credentials", lambda: [])
+    monkeypatch.setattr("agent.auxiliary_client.get_available_vision_backends", lambda: [])
+    monkeypatch.setattr(
+        "hermes_cli.models.probe_api_models",
+        lambda api_key, base_url: {
+            "models": ["llm"],
+            "probed_url": "http://localhost:8000/v1/models",
+            "resolved_base_url": "http://localhost:8000/v1",
+            "suggested_base_url": "http://localhost:8000/v1",
+            "used_fallback": True,
+        },
+    )
+
+    setup_model_provider(config)
+    save_config(config)
+
+    env = _read_env(tmp_path)
+    reloaded = load_config()
+
+    assert env.get("OPENAI_BASE_URL") == "http://localhost:8000/v1"
+    assert env.get("OPENAI_API_KEY") == "local-key"
+    assert reloaded["model"]["provider"] == "custom"
+    assert reloaded["model"]["base_url"] == "http://localhost:8000/v1"
+    assert reloaded["model"]["default"] == "llm"
+
+
 def test_setup_keep_current_config_provider_uses_provider_specific_model_menu(tmp_path, monkeypatch):
     """Keep-current should respect config-backed providers, not fall back to OpenRouter."""
     monkeypatch.setenv("HERMES_HOME", str(tmp_path))

tests/test_cli_provider_resolution.py

@@ -336,4 +336,42 @@ def test_cmd_model_falls_back_to_auto_on_invalid_provider(monkeypatch, capsys):
 
     assert "Warning:" in output
     assert "falling back to auto provider detection" in output.lower()
-    assert "No change." in output
+    assert "No change." in output
+
+
+def test_model_flow_custom_saves_verified_v1_base_url(monkeypatch, capsys):
+    monkeypatch.setattr(
+        "hermes_cli.config.get_env_value",
+        lambda key: "" if key in {"OPENAI_BASE_URL", "OPENAI_API_KEY"} else "",
+    )
+    saved_env = {}
+    monkeypatch.setattr("hermes_cli.config.save_env_value", lambda key, value: saved_env.__setitem__(key, value))
+    monkeypatch.setattr("hermes_cli.auth._save_model_choice", lambda model: saved_env.__setitem__("MODEL", model))
+    monkeypatch.setattr("hermes_cli.auth.deactivate_provider", lambda: None)
+    monkeypatch.setattr("hermes_cli.main._save_custom_provider", lambda *args, **kwargs: None)
+    monkeypatch.setattr(
+        "hermes_cli.models.probe_api_models",
+        lambda api_key, base_url: {
+            "models": ["llm"],
+            "probed_url": "http://localhost:8000/v1/models",
+            "resolved_base_url": "http://localhost:8000/v1",
+            "suggested_base_url": "http://localhost:8000/v1",
+            "used_fallback": True,
+        },
+    )
+    monkeypatch.setattr(
+        "hermes_cli.config.load_config",
+        lambda: {"model": {"default": "", "provider": "custom", "base_url": ""}},
+    )
+    monkeypatch.setattr("hermes_cli.config.save_config", lambda cfg: None)
+
+    answers = iter(["http://localhost:8000", "local-key", "llm"])
+    monkeypatch.setattr("builtins.input", lambda _prompt="": next(answers))
+
+    hermes_main._model_flow_custom({})
+    output = capsys.readouterr().out
+
+    assert "Saving the working base URL instead" in output
+    assert saved_env["OPENAI_BASE_URL"] == "http://localhost:8000/v1"
+    assert saved_env["OPENAI_API_KEY"] == "local-key"
+    assert saved_env["MODEL"] == "llm"