refactor: extract get_stt_model_from_config helper to eliminate DRY violation

Duplicated YAML config parsing for stt.model existed in gateway/run.py
and gateway/platforms/discord.py. Moved to a single helper in
transcription_tools.py and added 5 tests covering all edge cases.

gateway/platforms/discord.py

@@ -880,18 +880,8 @@ class DiscordAdapter(BasePlatformAdapter):
         try:
             await asyncio.to_thread(VoiceReceiver.pcm_to_wav, pcm_data, wav_path)
 
-            from tools.transcription_tools import transcribe_audio
-            # Read STT model from config.yaml
-            stt_model = None
-            try:
-                import yaml as _y
-                from pathlib import Path as _P
-                _cfg = _P(os.getenv("HERMES_HOME", _P.home() / ".hermes")) / "config.yaml"
-                if _cfg.exists():
-                    with open(_cfg) as _f:
-                        stt_model = (_y.safe_load(_f) or {}).get("stt", {}).get("model")
-            except Exception:
-                pass
+            from tools.transcription_tools import transcribe_audio, get_stt_model_from_config
+            stt_model = get_stt_model_from_config()
             result = await asyncio.to_thread(transcribe_audio, wav_path, model=stt_model)
 
             if not result.get("success"):

gateway/run.py

@@ -3323,20 +3323,10 @@ class GatewayRunner:
         Returns:
             The enriched message string with transcriptions prepended.
         """
-        from tools.transcription_tools import transcribe_audio
+        from tools.transcription_tools import transcribe_audio, get_stt_model_from_config
         import asyncio
 
-        # Read STT model from config.yaml (same key the CLI uses)
-        stt_model = None
-        try:
-            import yaml as _y
-            _cfg = _hermes_home / "config.yaml"
-            if _cfg.exists():
-                with open(_cfg) as _f:
-                    _data = _y.safe_load(_f) or {}
-                stt_model = _data.get("stt", {}).get("model")
-        except Exception:
-            pass
+        stt_model = get_stt_model_from_config()
 
         enriched_parts = []
         for path in audio_paths:

tests/tools/test_transcription_tools.py

@@ -1,4 +1,4 @@
-"""Tests for tools.transcription_tools -- provider resolution and model correction."""
+"""Tests for tools.transcription_tools -- provider resolution, model correction, config helper."""
 
 import os
 import struct
@@ -197,3 +197,47 @@ class TestTranscribeAudioSuccess:
             result = transcribe_audio(sample_wav)
 
         assert result["transcript"] == "hello world"
+
+
+# ============================================================================
+# get_stt_model_from_config
+# ============================================================================
+
+class TestGetSttModelFromConfig:
+    def test_returns_model_from_config(self, tmp_path, monkeypatch):
+        cfg = tmp_path / "config.yaml"
+        cfg.write_text("stt:\n  model: whisper-large-v3\n")
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+
+        from tools.transcription_tools import get_stt_model_from_config
+        assert get_stt_model_from_config() == "whisper-large-v3"
+
+    def test_returns_none_when_no_stt_section(self, tmp_path, monkeypatch):
+        cfg = tmp_path / "config.yaml"
+        cfg.write_text("tts:\n  provider: edge\n")
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+
+        from tools.transcription_tools import get_stt_model_from_config
+        assert get_stt_model_from_config() is None
+
+    def test_returns_none_when_no_config_file(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+
+        from tools.transcription_tools import get_stt_model_from_config
+        assert get_stt_model_from_config() is None
+
+    def test_returns_none_on_invalid_yaml(self, tmp_path, monkeypatch):
+        cfg = tmp_path / "config.yaml"
+        cfg.write_text(": : :\n  bad yaml [[[")
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+
+        from tools.transcription_tools import get_stt_model_from_config
+        assert get_stt_model_from_config() is None
+
+    def test_returns_none_when_model_key_missing(self, tmp_path, monkeypatch):
+        cfg = tmp_path / "config.yaml"
+        cfg.write_text("stt:\n  enabled: true\n")
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+
+        from tools.transcription_tools import get_stt_model_from_config
+        assert get_stt_model_from_config() is None

tools/transcription_tools.py

@@ -41,6 +41,24 @@ GROQ_BASE_URL = os.getenv("GROQ_BASE_URL", "https://api.groq.com/openai/v1")
 OPENAI_BASE_URL = os.getenv("STT_OPENAI_BASE_URL", "https://api.openai.com/v1")
 
 
+def get_stt_model_from_config() -> Optional[str]:
+    """Read the STT model name from ~/.hermes/config.yaml.
+
+    Returns the value of ``stt.model`` if present, otherwise ``None``.
+    Silently returns ``None`` on any error (missing file, bad YAML, etc.).
+    """
+    try:
+        import yaml
+        cfg_path = Path(os.getenv("HERMES_HOME", Path.home() / ".hermes")) / "config.yaml"
+        if cfg_path.exists():
+            with open(cfg_path) as f:
+                data = yaml.safe_load(f) or {}
+            return data.get("stt", {}).get("model")
+    except Exception:
+        pass
+    return None
+
+
 def _resolve_stt_provider() -> Tuple[Optional[str], Optional[str], str]:
     """Resolve which STT provider to use based on available API keys.