feat(providers): add GMI Cloud as a first-class API-key provider (#11955)

Add GMI Cloud (api.gmi-serving.com) as a full first-class API-key provider
with built-in auth, aliases, model catalog, CLI entry points, auxiliary client
routing, context length resolution, doctor checks, env var tracking, and docs.

- auth.py: ProviderConfig for 'gmi' (api_key, GMI_API_KEY / GMI_BASE_URL)
- providers.py: HermesOverlay with extra_env_vars for models.dev detection
- models.py: curated slash-form model catalog; live /v1/models fetch
- main.py: 'gmi' in _named_custom_provider_map and --provider choices
- model_metadata.py: _URL_TO_PROVIDER, _PROVIDER_PREFIXES, dedicated
  context-length probe block (GMI's /models has authoritative data)
- auxiliary_client.py: alias entries; _compat_model fix for slash-form
  models on cached aggregator-style clients; gmi aux default model
- doctor.py: GMI in provider connectivity checks
- config.py: GMI_API_KEY / GMI_BASE_URL in OPTIONAL_ENV_VARS
- conftest.py: explicit GMI_BASE_URL clearing (not caught by _API_KEY suffix)
- docs: providers.md, environment-variables.md, fallback-providers.md,
  configuration.md, quickstart.md (expands provider table)

Co-authored-by: Isaac Huang <isaachuang@Isaacs-MacBook-Pro.local>

agent/auxiliary_client.py

@@ -82,6 +82,8 @@ _PROVIDER_ALIASES = {
     "moonshot": "kimi-coding",
     "kimi-cn": "kimi-coding-cn",
     "moonshot-cn": "kimi-coding-cn",
+    "gmi-cloud": "gmi",
+    "gmicloud": "gmi",
     "minimax-china": "minimax-cn",
     "minimax_cn": "minimax-cn",
     "claude": "anthropic",
@@ -155,6 +157,7 @@ _API_KEY_PROVIDER_AUX_MODELS: Dict[str, str] = {
     "kimi-coding": "kimi-k2-turbo-preview",
     "stepfun": "step-3.5-flash",
     "kimi-coding-cn": "kimi-k2-turbo-preview",
+    "gmi": "anthropic/claude-opus-4.6",
     "minimax": "MiniMax-M2.7",
     "minimax-cn": "MiniMax-M2.7",
     "anthropic": "claude-haiku-4-5-20251001",
@@ -2558,12 +2561,19 @@ def _is_openrouter_client(client: Any) -> bool:
     return False
 
 
+def _cached_client_accepts_slash_models(client: Any, cached_default: Optional[str]) -> bool:
+    """Best-effort check for cached clients that accept ``vendor/model`` IDs."""
+    if _is_openrouter_client(client):
+        return True
+    return bool(cached_default and "/" in cached_default)
+
+
 def _compat_model(client: Any, model: Optional[str], cached_default: Optional[str]) -> Optional[str]:
-    """Drop OpenRouter-format model slugs (with '/') for non-OpenRouter clients.
+    """Keep slash-bearing model IDs only for cached clients that support them.
 
     Mirrors the guard in resolve_provider_client() which is skipped on cache hits.
     """
-    if model and "/" in model and not _is_openrouter_client(client):
+    if model and "/" in model and not _cached_client_accepts_slash_models(client, cached_default):
         return cached_default
     return model or cached_default
 

agent/model_metadata.py

@@ -51,6 +51,7 @@ _PROVIDER_PREFIXES: frozenset[str] = frozenset({
     "qwen-oauth",
     "xiaomi",
     "arcee",
+    "gmi",
     "custom", "local",
     # Common aliases
     "google", "google-gemini", "google-ai-studio",
@@ -60,6 +61,7 @@ _PROVIDER_PREFIXES: frozenset[str] = frozenset({
     "stepfun", "opencode", "zen", "go", "vercel", "kilo", "dashscope", "aliyun", "qwen",
     "mimo", "xiaomi-mimo",
     "arcee-ai", "arceeai",
+    "gmi-cloud", "gmicloud",
     "xai", "x-ai", "x.ai", "grok",
     "nvidia", "nim", "nvidia-nim", "nemotron",
     "qwen-portal",
@@ -307,6 +309,7 @@ _URL_TO_PROVIDER: Dict[str, str] = {
     "integrate.api.nvidia.com": "nvidia",
     "api.xiaomimimo.com": "xiaomi",
     "xiaomimimo.com": "xiaomi",
+    "api.gmi-serving.com": "gmi",
     "ollama.com": "ollama-cloud",
 }
 
@@ -702,6 +705,29 @@ def fetch_endpoint_model_metadata(
     return {}
 
 
+def _resolve_endpoint_context_length(
+    model: str,
+    base_url: str,
+    api_key: str = "",
+) -> Optional[int]:
+    """Resolve context length from an endpoint's live ``/models`` metadata."""
+    endpoint_metadata = fetch_endpoint_model_metadata(base_url, api_key=api_key)
+    matched = endpoint_metadata.get(model)
+    if not matched:
+        if len(endpoint_metadata) == 1:
+            matched = next(iter(endpoint_metadata.values()))
+        else:
+            for key, entry in endpoint_metadata.items():
+                if model in key or key in model:
+                    matched = entry
+                    break
+    if matched:
+        context_length = matched.get("context_length")
+        if isinstance(context_length, int):
+            return context_length
+    return None
+
+
 def _get_context_cache_path() -> Path:
     """Return path to the persistent context length cache file."""
     from hermes_constants import get_hermes_home
@@ -1295,22 +1321,9 @@ def get_model_context_length(
     # returns 128k) instead of the model's full context (400k).  models.dev
     # has the correct per-provider values and is checked at step 5+.
     if _is_custom_endpoint(base_url) and not _is_known_provider_base_url(base_url):
-        endpoint_metadata = fetch_endpoint_model_metadata(base_url, api_key=api_key)
-        matched = endpoint_metadata.get(model)
-        if not matched:
-            # Single-model servers: if only one model is loaded, use it
-            if len(endpoint_metadata) == 1:
-                matched = next(iter(endpoint_metadata.values()))
-            else:
-                # Fuzzy match: substring in either direction
-                for key, entry in endpoint_metadata.items():
-                    if model in key or key in model:
-                        matched = entry
-                        break
-        if matched:
-            context_length = matched.get("context_length")
-            if isinstance(context_length, int):
-                return context_length
+        context_length = _resolve_endpoint_context_length(model, base_url, api_key=api_key)
+        if context_length is not None:
+            return context_length
         if not _is_known_provider_base_url(base_url):
             # 3. Try querying local server directly
             if is_local_endpoint(base_url):
@@ -1374,6 +1387,12 @@ def get_model_context_length(
             if base_url:
                 save_context_length(model, base_url, codex_ctx)
             return codex_ctx
+    if effective_provider == "gmi" and base_url:
+        # GMI exposes authoritative context_length via /models, but it is not
+        # in models.dev yet. Preserve that higher-fidelity endpoint lookup.
+        ctx = _resolve_endpoint_context_length(model, base_url, api_key=api_key)
+        if ctx is not None:
+            return ctx
     if effective_provider:
         from agent.models_dev import lookup_models_dev_context
         ctx = lookup_models_dev_context(effective_provider, model)