fix: pass config_context_length to /model display and gateway fallback paths

agent/model_metadata.py

@@ -938,6 +938,69 @@ def _resolve_nous_context_length(model: str) -> Optional[int]:
     return None
 
 
+def read_config_context_length(
+    model: str,
+    base_url: str = "",
+) -> int | None:
+    """Read config_context_length from config.yaml for the given model.
+
+    Checks model.context_length first, then custom_providers[].models.<model>.context_length.
+    Returns None if not configured.
+    """
+    try:
+        from hermes_cli.config import load_config, get_compatible_custom_providers
+    except ImportError:
+        return None
+
+    try:
+        cfg = load_config()
+    except Exception:
+        return None
+
+    # 1. model.context_length (top-level override)
+    model_cfg = cfg.get("model", {})
+    if isinstance(model_cfg, dict):
+        raw = model_cfg.get("context_length")
+        if raw is not None:
+            try:
+                val = int(raw)
+                if val > 0:
+                    return val
+            except (TypeError, ValueError):
+                pass
+
+    # 2. custom_providers[].models.<model>.context_length
+    if base_url:
+        try:
+            custom_providers = get_compatible_custom_providers(cfg)
+        except Exception:
+            custom_providers = cfg.get("custom_providers", [])
+            if not isinstance(custom_providers, list):
+                custom_providers = []
+
+        normalized_url = base_url.rstrip("/")
+        for cp_entry in custom_providers:
+            if not isinstance(cp_entry, dict):
+                continue
+            cp_url = (cp_entry.get("base_url") or "").rstrip("/")
+            if cp_url and cp_url == normalized_url:
+                cp_models = cp_entry.get("models", {})
+                if isinstance(cp_models, dict):
+                    cp_model_cfg = cp_models.get(model, {})
+                    if isinstance(cp_model_cfg, dict):
+                        cp_ctx = cp_model_cfg.get("context_length")
+                        if cp_ctx is not None:
+                            try:
+                                val = int(cp_ctx)
+                                if val > 0:
+                                    return val
+                            except (TypeError, ValueError):
+                                pass
+                break
+
+    return None
+
+
 def get_model_context_length(
     model: str,
     base_url: str = "",

cli.py

@@ -4712,11 +4712,16 @@ def _apply_model_switch_result(self, result, persist_global: bool) -> None:
             _cprint(f"    Capabilities: {mi.format_capabilities()}")
         else:
             try:
-                from agent.model_metadata import get_model_context_length
+                from agent.model_metadata import get_model_context_length, read_config_context_length
+                _config_ctx = read_config_context_length(
+                    result.new_model,
+                    base_url=result.base_url or self.base_url or "",
+                )
                 ctx = get_model_context_length(
                     result.new_model,
                     base_url=result.base_url or self.base_url,
                     api_key=result.api_key or self.api_key,
+                    config_context_length=_config_ctx,
                     provider=result.target_provider,
                 )
                 _cprint(f"    Context: {ctx:,} tokens")
@@ -4939,11 +4944,16 @@ def _handle_model_switch(self, cmd_original: str):
         else:
             # Fallback to old context length lookup
             try:
-                from agent.model_metadata import get_model_context_length
+                from agent.model_metadata import get_model_context_length, read_config_context_length
+                _config_ctx = read_config_context_length(
+                    result.new_model,
+                    base_url=result.base_url or self.base_url or "",
+                )
                 ctx = get_model_context_length(
                     result.new_model,
                     base_url=result.base_url or self.base_url,
                     api_key=result.api_key or self.api_key,
+                    config_context_length=_config_ctx,
                     provider=result.target_provider,
                 )
                 _cprint(f"    Context: {ctx:,} tokens")

gateway/run.py

@@ -3645,12 +3645,17 @@ async def _prepare_inbound_message_text(
         if "@" in message_text:
             try:
                 from agent.context_references import preprocess_context_references_async
-                from agent.model_metadata import get_model_context_length
+                from agent.model_metadata import get_model_context_length, read_config_context_length
 
                 _msg_cwd = os.environ.get("TERMINAL_CWD", os.path.expanduser("~"))
+                _config_ctx = read_config_context_length(
+                    self._model,
+                    base_url=self._base_url or "",
+                )
                 _msg_ctx_len = get_model_context_length(
                     self._model,
                     base_url=self._base_url or "",
+                    config_context_length=_config_ctx,
                 )
                 _ctx_result = await preprocess_context_references_async(
                     message_text,
@@ -5349,11 +5354,16 @@ async def _on_model_selected(
             lines.append(f"Capabilities: {mi.format_capabilities()}")
         else:
             try:
-                from agent.model_metadata import get_model_context_length
+                from agent.model_metadata import get_model_context_length, read_config_context_length
+                _config_ctx = read_config_context_length(
+                    result.new_model,
+                    base_url=result.base_url or current_base_url or "",
+                )
                 ctx = get_model_context_length(
                     result.new_model,
                     base_url=result.base_url or current_base_url,
                     api_key=result.api_key or current_api_key,
+                    config_context_length=_config_ctx,
                     provider=result.target_provider,
                 )
                 lines.append(f"Context: {ctx:,} tokens")

tests/agent/test_model_metadata.py

@@ -28,6 +28,7 @@
     get_model_context_length,
     get_next_probe_tier,
     get_cached_context_length,
+    read_config_context_length,
     parse_context_limit_from_error,
     save_context_length,
     fetch_model_metadata,
@@ -711,3 +712,108 @@ def test_special_chars_in_model_name(self, tmp_path):
         with patch("agent.model_metadata._get_context_cache_path", return_value=cache_file):
             save_context_length(model, url, 200000)
             assert get_cached_context_length(model, url) == 200000
+
+
+# =========================================================================
+# read_config_context_length — config.yaml context_length resolution
+# =========================================================================
+
+class TestReadConfigContextLength:
+    """Tests for read_config_context_length() helper."""
+
+    def test_model_context_length_from_config(self):
+        """model.context_length in config is returned."""
+        mock_cfg = {"model": {"context_length": 500000}}
+        with patch("hermes_cli.config.load_config", return_value=mock_cfg):
+            result = read_config_context_length("any-model")
+        assert result == 500000
+
+    def test_custom_providers_context_length(self):
+        """custom_providers[].models.<model>.context_length is returned."""
+        mock_cfg = {
+            "custom_providers": [{
+                "name": "my-provider",
+                "base_url": "https://api.example.com/v1",
+                "models": {
+                    "gpt-5.4": {"context_length": 1000000},
+                },
+            }],
+        }
+        with patch("hermes_cli.config.load_config", return_value=mock_cfg), \
+             patch("hermes_cli.config.get_compatible_custom_providers", return_value=mock_cfg["custom_providers"]):
+            result = read_config_context_length(
+                "gpt-5.4",
+                base_url="https://api.example.com/v1",
+            )
+        assert result == 1000000
+
+    def test_model_context_length_takes_priority(self):
+        """model.context_length overrides custom_providers per-model."""
+        mock_cfg = {
+            "model": {"context_length": 256000},
+            "custom_providers": [{
+                "name": "my-provider",
+                "base_url": "https://api.example.com/v1",
+                "models": {"gpt-5.4": {"context_length": 1000000}},
+            }],
+        }
+        with patch("hermes_cli.config.load_config", return_value=mock_cfg):
+            result = read_config_context_length(
+                "gpt-5.4",
+                base_url="https://api.example.com/v1",
+            )
+        assert result == 256000
+
+    def test_no_config_returns_none(self):
+        """No config data returns None."""
+        with patch("hermes_cli.config.load_config", return_value={}):
+            result = read_config_context_length("some-model")
+        assert result is None
+
+    def test_invalid_context_length_ignored(self):
+        """Non-integer context_length is ignored."""
+        mock_cfg = {"model": {"context_length": "not-a-number"}}
+        with patch("hermes_cli.config.load_config", return_value=mock_cfg):
+            result = read_config_context_length("some-model")
+        assert result is None
+
+    def test_zero_context_length_ignored(self):
+        """context_length=0 is treated as unset."""
+        mock_cfg = {"model": {"context_length": 0}}
+        with patch("hermes_cli.config.load_config", return_value=mock_cfg):
+            result = read_config_context_length("some-model")
+        assert result is None
+
+    def test_base_url_mismatch_skips_custom_providers(self):
+        """Non-matching base_url skips custom_providers lookup."""
+        mock_cfg = {
+            "custom_providers": [{
+                "name": "my-provider",
+                "base_url": "https://other.example.com/v1",
+                "models": {"gpt-5.4": {"context_length": 1000000}},
+            }],
+        }
+        with patch("hermes_cli.config.load_config", return_value=mock_cfg), \
+             patch("hermes_cli.config.get_compatible_custom_providers", return_value=mock_cfg["custom_providers"]):
+            result = read_config_context_length(
+                "gpt-5.4",
+                base_url="https://api.example.com/v1",
+            )
+        assert result is None
+
+    def test_trailing_slash_normalized(self):
+        """Trailing slashes in base_url are normalized for matching."""
+        mock_cfg = {
+            "custom_providers": [{
+                "name": "my-provider",
+                "base_url": "https://api.example.com/v1",
+                "models": {"gpt-5.4": {"context_length": 1000000}},
+            }],
+        }
+        with patch("hermes_cli.config.load_config", return_value=mock_cfg), \
+             patch("hermes_cli.config.get_compatible_custom_providers", return_value=mock_cfg["custom_providers"]):
+            result = read_config_context_length(
+                "gpt-5.4",
+                base_url="https://api.example.com/v1/",
+            )
+        assert result == 1000000