fail soft on unmatched instrument names, add matching-status output

app.py

@@ -18,13 +18,14 @@ except ImportError:
                 return func
 
 import tempfile
+from pathlib import Path
 
 import gradio as gr
 import torch
 from pyharp import ModelCard, build_endpoint
 
 from muscriptor import TranscriptionModel
-from muscriptor.tokenizer.mt3 import resolve_instrument_names
+from muscriptor.tokenizer.mt3 import MT3_FULL_PLUS_GROUP_NAMES, resolve_instrument_names
 
 model_card = ModelCard(
     name="MuScriptor",
@@ -36,6 +37,8 @@ model_card = ModelCard(
     tags=["transcription", "midi", "multi-instrument"],
 )
 
+_VALID_INSTRUMENTS = ", ".join(MT3_FULL_PLUS_GROUP_NAMES)
+
 _models: dict[str, TranscriptionModel] = {}
 
 
@@ -51,19 +54,34 @@ def _get_model(variant: str) -> TranscriptionModel:
     return _models[variant]
 
 
-def _parse_instruments(text: str) -> list[str] | None:
-    """Turn the comma-separated instruments box into exact group names.
+def _resolve_instruments(text: str) -> tuple[list[str] | None, str]:
+    """Resolve the comma-separated instruments box into exact group names.
 
-    Accepts unambiguous abbreviations, same as the CLI's --instruments.
-    Blank input means "no restriction, let the model decide".
+    Names that don't resolve are dropped rather than raised: HARP's client
+    shows generic error message, so an error here would not reach the user. 
+    Second value returns what happened as a .txt output
     """
     tokens = [t for t in text.split(",") if t.strip()]
     if not tokens:
-        return None
-    try:
-        return resolve_instrument_names(tokens)
-    except ValueError as e:
-        raise gr.Error(str(e))
+        return None, "No instrument restriction requested."
+
+    resolved: list[str] = []
+    problems: list[str] = []
+    for token in tokens:
+        try:
+            resolved.extend(resolve_instrument_names([token]))
+        except ValueError as e:
+            problems.append(str(e))
+
+    if not problems:
+        return resolved, f"Matched: {', '.join(resolved)}."
+
+    note = "; ".join(problems)
+    if resolved:
+        note = f"Matched: {', '.join(resolved)}. Ignored: {note}"
+    else:
+        note = f"No valid instrument names found, transcribing unrestricted. {note}"
+    return (resolved or None), note
 
 
 @spaces.GPU
@@ -74,10 +92,10 @@ def process_fn(
     instruments_text: str,
     use_sampling: bool,
     temperature: float,
-) -> str:
-    """Transcribe the input audio to a MIDI file and return its path."""
+) -> tuple[str, str]:
+    """Transcribe the input audio to MIDI, plus a note on the Instruments field."""
     model = _get_model(variant)
-    instruments = _parse_instruments(instruments_text)
+    instruments, instrument_note = _resolve_instruments(instruments_text)
 
     midi_bytes = model.transcribe_to_midi(
         input_audio_path,
@@ -90,7 +108,12 @@ def process_fn(
         f.write(midi_bytes)
         output_midi_path = f.name
 
-    return output_midi_path
+    notes_text = f"{Path(input_audio_path).name}\n\nInstrument Matching\n{instrument_note}\n"
+    with tempfile.NamedTemporaryFile(mode="w", suffix=".txt", delete=False) as f:
+        f.write(notes_text)
+        output_notes_path = f.name
+
+    return output_midi_path, output_notes_path
 
 
 with gr.Blocks() as demo:
@@ -105,7 +128,7 @@ with gr.Blocks() as demo:
         gr.Textbox(
             value="",
             label="Instruments",
-            info="Comma-separated instrument names to restrict decoding to, e.g. acoustic_piano,violin,trumpet,drums,etc. Leave blank to let the model detect instruments on its own.",
+            info=f"Comma-separated instrument names to restrict decoding to. Valid names: {_VALID_INSTRUMENTS}. Leave blank to let the model detect instruments on its own.",
         ),
         gr.Checkbox(
             label="Use Sampling",
@@ -124,6 +147,9 @@ with gr.Blocks() as demo:
         gr.File(type="filepath", file_types=[".mid", ".midi"], label="Output MIDI").set_info(
             "Transcribed MIDI notes."
         ),
+        gr.File(type="filepath", file_types=[".txt"], label="Instrument Matching").set_info(
+            "Which requested instrument names were matched or ignored."
+        ),
     ]
 
     build_endpoint(