fix(config): stop provider-key warn-storm that stalls Windows logging

_normalize_custom_provider_entry() runs on every load_picker_context()
call (per picker/inventory request) and warned each time for (a) the
redundant `provider` key that Hermes' own config writer emits into
provider entries and (b) any other unknown key. On Windows the serve
launcher+worker pair share one rotating log via concurrent-log-handler's
cross-process lock, so that per-load warning volume drove 'Cannot acquire
lock after 20 attempts' retries that pegged a core, stalled the event
loop ~14s, and dropped every desktop/TUI WebSocket while /health stayed
green (gateway looked down; dashboard looked fine).

- Accept `provider` as a known key (silently ignored) so self-written
  legacy configs don't warn.
- Deduplicate the normalizer's warnings per (provider, signature) so a
  static config quirk is surfaced once, not on every inventory load.

Adds regression tests for both.

Fixes #58265

hermes_cli/config.py

@@ -4470,6 +4470,26 @@ def get_missing_skill_config_vars() -> List[Dict[str, Any]]:
     return missing
 
 
+# ``_normalize_custom_provider_entry`` runs on every ``load_picker_context()``
+# call (i.e. per interactive picker/inventory request), so any warning it emits
+# fires repeatedly for the same static config. Deduplicate per (provider,
+# signature): on Windows a repeated-warning storm contends on
+# ``concurrent-log-handler``'s cross-process rotation lock and can peg a core /
+# stall the gateway/serve event loop. The cache lives for the process lifetime.
+_PROVIDER_NORMALIZE_WARNED: set = set()
+
+
+def _warn_once_per_provider(
+    provider_key: str, signature: str, msg: str, *args: Any
+) -> None:
+    """Emit ``logger.warning(msg, *args)`` at most once per (provider, signature)."""
+    dedup_key = (provider_key or "?", signature)
+    if dedup_key in _PROVIDER_NORMALIZE_WARNED:
+        return
+    _PROVIDER_NORMALIZE_WARNED.add(dedup_key)
+    logger.warning(msg, *args)
+
+
 def _normalize_custom_provider_entry(
     entry: Any,
     *,
@@ -4496,6 +4516,11 @@ def _normalize_custom_provider_entry(
     if "api_key_env" in entry and "key_env" not in entry:
         entry["key_env"] = entry["api_key_env"]
     _KNOWN_KEYS = {
+        # ``provider`` duplicates the ``providers.<name>`` mapping key and is
+        # unused here, but Hermes' own config writer has historically emitted it
+        # into provider entries. Accept it silently so those (self-written)
+        # configs don't warn on every load.
+        "provider",
         "name", "api", "url", "base_url", "api_key", "key_env", "api_key_env",
         "api_mode", "transport", "model", "default_model", "models",
         "context_length", "rate_limit_delay",
@@ -4505,7 +4530,8 @@ def _normalize_custom_provider_entry(
     }
     for camel, snake in _CAMEL_ALIASES.items():
         if camel in entry and snake not in entry:
-            logger.warning(
+            _warn_once_per_provider(
+                provider_key, f"camel:{camel}",
                 "providers.%s: camelCase key '%s' auto-mapped to '%s' "
                 "(use snake_case to avoid this warning)",
                 provider_key or "?", camel, snake,
@@ -4513,7 +4539,8 @@ def _normalize_custom_provider_entry(
             entry[snake] = entry[camel]
     unknown = set(entry.keys()) - _KNOWN_KEYS - set(_CAMEL_ALIASES.keys())
     if unknown:
-        logger.warning(
+        _warn_once_per_provider(
+            provider_key, "unknown:" + ",".join(sorted(unknown)),
             "providers.%s: unknown config keys ignored: %s",
             provider_key or "?", ", ".join(sorted(unknown)),
         )

tests/hermes_cli/test_provider_config_validation.py

@@ -6,13 +6,26 @@ accepted as base_url, and unknown keys go unreported.
 
 import logging
 
+import pytest
 
-from hermes_cli.config import _normalize_custom_provider_entry
+from hermes_cli.config import (
+    _PROVIDER_NORMALIZE_WARNED,
+    _normalize_custom_provider_entry,
+)
 
 
 class TestNormalizeCustomProviderEntry:
     """Tests for _normalize_custom_provider_entry validation."""
 
+    @pytest.fixture(autouse=True)
+    def _reset_warn_cache(self):
+        """The normalizer deduplicates its warnings via a process-lifetime
+        cache; clear it around each test so warning assertions are independent
+        of test order."""
+        _PROVIDER_NORMALIZE_WARNED.clear()
+        yield
+        _PROVIDER_NORMALIZE_WARNED.clear()
+
     def test_valid_entry_snake_case(self):
         """Standard snake_case entry should normalize correctly."""
         entry = {
@@ -89,6 +102,40 @@ class TestNormalizeCustomProviderEntry:
         assert result is not None
         assert any("unknown config keys" in r.message.lower() for r in caplog.records)
 
+    def test_provider_key_not_flagged_unknown(self, caplog):
+        """A redundant ``provider`` key (written by Hermes' own config writer)
+        must be accepted silently — not reported as an unknown key. Regression
+        for the config warn-storm that deadlocked Windows logging."""
+        entry = {
+            "provider": "",
+            "base_url": "https://api.example.com/v1",
+            "api_key": "***",
+        }
+        with caplog.at_level(logging.WARNING):
+            result = _normalize_custom_provider_entry(entry, provider_key="onyx-6000")
+        assert result is not None
+        assert not any("unknown config keys" in r.message.lower() for r in caplog.records)
+
+    def test_unknown_keys_warned_once_per_signature(self, caplog):
+        """Repeated normalization of the same entry (as happens on every
+        picker/inventory load) must warn only once — otherwise the warning
+        storms the log handler. Fix B."""
+        entry = {
+            "base_url": "https://api.example.com/v1",
+            "api_key": "***",
+            "unknownField": "value",
+        }
+        with caplog.at_level(logging.WARNING):
+            for _ in range(5):
+                _normalize_custom_provider_entry(
+                    dict(entry), provider_key="test"
+                )
+        unknown_warnings = [
+            r for r in caplog.records
+            if "unknown config keys" in r.message.lower()
+        ]
+        assert len(unknown_warnings) == 1
+
     def test_timeout_keys_not_flagged_unknown(self, caplog):
         """request_timeout_seconds and stale_timeout_seconds should not produce warnings."""
         entry = {