Show debug info in chat when API key not found

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app.py

@@ -551,24 +551,25 @@ STAGE_FOCUS = {
 def get_client():
     """Initialize Anthropic client - try multiple possible secret names"""
     api_key = (
+        os.environ.get("ANTHROPIC_API_KEY") or
         os.environ.get("anthropic_key") or
         os.environ.get("ANTHROPIC_KEY") or
-        os.environ.get("ANTHROPIC_API_KEY") or
         os.environ.get("anthropic_api_key")
     )
     if not api_key:
-        # Debug: show env vars that contain 'key' or 'api' (names only)
-        relevant_vars = [k for k in os.environ.keys() if 'key' in k.lower() or 'api' in k.lower() or 'anthropic' in k.lower()]
-        raise ValueError(
-            f"Anthropic API key not found. Available relevant env vars: {relevant_vars}. "
-            "Please add a secret named ANTHROPIC_API_KEY in Space Settings > Repository secrets."
-        )
+        return None
     return anthropic.Anthropic(api_key=api_key)
 
 def call_claude(system_prompt, messages, context=""):
     """Call Claude API with given prompts"""
     client = get_client()
 
+    if client is None:
+        # Show helpful message about which env vars we checked
+        checked = ["ANTHROPIC_API_KEY", "anthropic_key", "ANTHROPIC_KEY", "anthropic_api_key"]
+        available = [k for k in os.environ.keys() if 'key' in k.lower() or 'api' in k.lower() or 'anthrop' in k.lower()]
+        return f"API key not found. Checked: {checked}. Found env vars containing 'key'/'api'/'anthrop': {available}. Please add ANTHROPIC_API_KEY in Space Settings > Repository secrets, then restart the Space."
+
     if context:
         user_content = f"{context}\n\nUser message: {messages[-1]['content']}" if messages else context
     else: