Remove placeholder text box and add graceful error handling

app.py

@@ -47,7 +47,7 @@ default_schema = PRESETS[default_title]["schema"] if default_title else "{}"
 def run_comparison(context_str: str, schema_json_str: str):
     if not context_str or not context_str.strip():
         yield (
-            "<div style='color: #dc2626; font-weight: 600;'>Please provide a context prompt.</div>",
+            "<div style='color: #dc2626; font-weight: 600; padding: 6px 12px;'>Please provide a context prompt.</div>",
             "{}",
             "0.0 ms",
             "{}",
@@ -60,7 +60,7 @@ def run_comparison(context_str: str, schema_json_str: str):
         schema = StructuredSchema(schema_dict)
     except Exception as e:
         yield (
-            f"<div style='color: #dc2626; font-weight: 600;'>Invalid Schema JSON: {e}</div>",
+            f"<div style='color: #dc2626; font-weight: 600; padding: 6px 12px;'>Invalid Schema JSON: {e}</div>",
             "{}",
             "0.0 ms",
             "{}",
@@ -68,51 +68,62 @@ def run_comparison(context_str: str, schema_json_str: str):
         )
         return
 
-    # 1. Run Parallel Constrained Decoding first
-    parallel_res = run_parallel_generation(context_str, schema)
-    parallel_ms = parallel_res["elapsed_ms"]
-    parallel_json_str = json.dumps(parallel_res["parsed_json"], indent=2)
-    parallel_time_badge = f"{parallel_ms:.1f} ms"
-
-    summary_intermediate = f"""
-    <div style="background: #f0fdf4; border: 1px solid #bbf7d0; border-radius: 9999px; padding: 6px 16px; display: inline-flex; align-items: center; gap: 8px; font-family: monospace; font-size: 14px;">
-        <span style="color: #16a34a; font-weight: 700;">PARALLEL EVALUATION COMPLETE: {parallel_time_badge}</span>
-        <span style="color: #94a3b8;">·</span>
-        <span style="color: #64748b;">Evaluating normal autoregressive baseline...</span>
-    </div>
-    """
-    
-    yield (
-        summary_intermediate,
-        parallel_json_str,
-        parallel_time_badge,
-        "// Running sequential autoregressive baseline forward passes...",
-        "Evaluating..."
-    )
+    try:
+        # 1. Run Parallel Constrained Decoding first
+        parallel_res = run_parallel_generation(context_str, schema)
+        parallel_ms = parallel_res["elapsed_ms"]
+        parallel_json_str = json.dumps(parallel_res["parsed_json"], indent=2)
+        parallel_time_badge = f"{parallel_ms:.1f} ms"
+
+        summary_intermediate = f"""
+        <div style="background: #f0fdf4; border: 1px solid #bbf7d0; border-radius: 9999px; padding: 6px 16px; display: inline-flex; align-items: center; gap: 8px; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; font-size: 14px;">
+            <span style="color: #16a34a; font-weight: 700;">Parallel Done: {parallel_time_badge}</span>
+            <span style="color: #94a3b8;">·</span>
+            <span style="color: #64748b;">Evaluating normal autoregressive baseline...</span>
+        </div>
+        """
+        
+        yield (
+            summary_intermediate,
+            parallel_json_str,
+            parallel_time_badge,
+            "// Running sequential autoregressive baseline forward passes...",
+            "Evaluating..."
+        )
 
-    # 2. Run Naive generation baseline
-    naive_res = run_naive_generation(context_str, schema)
-    naive_ms = naive_res["elapsed_ms"]
-    naive_json_str = json.dumps(naive_res["parsed_json"], indent=2) if naive_res["parsed_json"] else naive_res["raw_text"]
-    naive_time_badge = f"{naive_ms:.1f} ms"
-
-    speedup = round(naive_ms / max(parallel_ms, 1.0), 1)
-
-    final_summary_html = f"""
-    <div style="background: #f0fdf4; border: 1px solid #bbf7d0; border-radius: 9999px; padding: 8px 20px; display: inline-flex; align-items: center; gap: 10px; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; font-size: 15px; box-shadow: 0 1px 3px rgba(0,0,0,0.05);">
-        <span style="color: #16a34a; font-weight: 800; font-size: 16px; letter-spacing: 0.5px;">{speedup}x FASTER</span>
-        <span style="color: #cbd5e1; font-weight: 600;">·</span>
-        <span style="color: #334155; font-weight: 600; font-family: monospace;">{parallel_time_badge} vs {naive_time_badge}</span>
-    </div>
-    """
-
-    yield (
-        final_summary_html,
-        parallel_json_str,
-        parallel_time_badge,
-        naive_json_str,
-        naive_time_badge
-    )
+        # 2. Run Naive generation baseline
+        naive_res = run_naive_generation(context_str, schema)
+        naive_ms = naive_res["elapsed_ms"]
+        naive_json_str = json.dumps(naive_res["parsed_json"], indent=2) if naive_res.get("parsed_json") else naive_res.get("raw_text", "")
+        naive_time_badge = f"{naive_ms:.1f} ms"
+
+        speedup = round(naive_ms / max(parallel_ms, 1.0), 1)
+
+        final_summary_html = f"""
+        <div style="background: #f0fdf4; border: 1px solid #bbf7d0; border-radius: 9999px; padding: 8px 20px; display: inline-flex; align-items: center; gap: 10px; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; font-size: 15px; box-shadow: 0 1px 3px rgba(0,0,0,0.05);">
+            <span style="color: #16a34a; font-weight: 800; font-size: 16px; letter-spacing: 0.5px;">{speedup}x FASTER</span>
+            <span style="color: #cbd5e1; font-weight: 600;">·</span>
+            <span style="color: #334155; font-weight: 600; font-family: monospace;">{parallel_time_badge} vs {naive_time_badge}</span>
+        </div>
+        """
+
+        yield (
+            final_summary_html,
+            parallel_json_str,
+            parallel_time_badge,
+            naive_json_str,
+            naive_time_badge
+        )
+    except Exception as err:
+        import traceback
+        err_msg = f"{err}\n{traceback.format_exc()}"
+        yield (
+            f"<div style='color: #dc2626; background: #fef2f2; border: 1px solid #fecaca; border-radius: 8px; padding: 10px 14px; font-family: monospace; font-size: 13px;'>Error: {err}</div>",
+            "{}",
+            "0.0 ms",
+            f"Error details:\n{err_msg}",
+            "0.0 ms"
+        )
 
 
 with gr.Blocks(title="Parallel Constrained Decision Engine") as demo:
@@ -128,11 +139,7 @@ with gr.Blocks(title="Parallel Constrained Decision Engine") as demo:
         )
         btn_run = gr.Button("⚡ Run Comparison", variant="primary", scale=1)
 
-    summary_banner = gr.HTML(value="""
-    <div style="background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 9999px; padding: 6px 16px; display: inline-flex; align-items: center; font-family: monospace; font-size: 14px; color: #64748b;">
-        Select a preset and click "Run Comparison" to start
-    </div>
-    """)
+    summary_banner = gr.HTML(value="")
 
     with gr.Row():
         with gr.Column(scale=1):