diff --git a/BUILDER_APPS_MIGRATION.md b/BUILDER_APPS_MIGRATION.md
index 1f719c4b..23465aeb 100644
--- a/BUILDER_APPS_MIGRATION.md
+++ b/BUILDER_APPS_MIGRATION.md
@@ -50,7 +50,19 @@ Das Projekt nutzt ein geteiltes `helpers.py`, das auf der alten OpenAI Python Li
     ```text
     openai==0.28.1
     # weitere deps...
+### 1.5 Python Syntax & F-Strings
+Multi-Line f-Strings mit JSON-Beispielen (`{...}`) sind extrem fehleranfällig (Escaping, Einrückung).
+*   **Best Practice:** Komplexe JSON-Daten oder Strings **vorher** in Variablen speichern und dann einfügen.
+    ```python
+    # Schlecht:
+    prompt = f"""Daten: {json.dumps(data.get('nested'))}"""
+    
+    # Gut:
+    nested_json = json.dumps(data.get('nested'))
+    prompt = f"""Daten: {nested_json}"""
     ```
+*   **Signaturen prüfen:** Shared Libraries (`helpers.py`) haben oft ältere Signaturen.
+    *   Beispiel: `call_openai_chat` unterstützt oft kein `system_message` Argument. Stattdessen Prompt manuell zusammenbauen (`sys_instr + "\n\n" + prompt`).
 
 ---
 
diff --git a/gtm_architect_orchestrator.py b/gtm_architect_orchestrator.py
index 7e1da592..b1fee724 100644
--- a/gtm_architect_orchestrator.py
+++ b/gtm_architect_orchestrator.py
@@ -154,14 +154,17 @@ Output JSON format ONLY.
 """
     # Fix: Prepend system instruction manually
     full_extraction_prompt = sys_instr + "\n\n" + extraction_prompt
-    extraction_response = call_openai_chat(full_extraction_prompt, json_mode=True)
+    extraction_response = call_openai_chat(full_extraction_prompt, response_format_json=True)
     extraction_data = json.loads(extraction_response)
 
+    features_json = json.dumps(extraction_data.get('features'))
+    constraints_json = json.dumps(extraction_data.get('constraints'))
+
     conflict_prompt = f"""
 PHASE 1-B: PORTFOLIO CONFLICT CHECK
 
-New Product Features: {json.dumps(extraction_data.get('features'))}
-New Product Constraints: {json.dumps(extraction_data.get('constraints'))}
+New Product Features: {features_json}
+New Product Constraints: {constraints_json}
 
 Existing Portfolio:
 1. "Indoor Scrubber 50": Indoor cleaning, hard floor, supermarkets.
@@ -174,8 +177,8 @@ Output JSON format ONLY.
 """ if lang == 'en' else f"""
 PHASE 1-B: PORTFOLIO CONFLICT CHECK
 
-Neue Produkt-Features: {json.dumps(extraction_data.get('features'))}
-Neue Produkt-Constraints: {json.dumps(extraction_data.get('constraints'))}
+Neue Produkt-Features: {features_json}
+Neue Produkt-Constraints: {constraints_json}
 
 Existierendes Portfolio:
 1. "Indoor Scrubber 50": Innenreinigung, Hartboden, Supermärkte.
@@ -188,7 +191,7 @@ Output JSON format ONLY.
 """
     # Fix: Prepend system instruction manually
     full_conflict_prompt = sys_instr + "\n\n" + conflict_prompt
-    conflict_response = call_openai_chat(full_conflict_prompt, json_mode=True)
+    conflict_response = call_openai_chat(full_conflict_prompt, response_format_json=True)
     conflict_data = json.loads(conflict_response)
     
     final_result = {{**extraction_data, **conflict_data}}
@@ -199,10 +202,13 @@ def discover_icps(data):
     lang = data.get('language', 'de')
     sys_instr = get_system_instruction(lang)
 
+    features_json = json.dumps(phase1_result.get('features'))
+    constraints_json = json.dumps(phase1_result.get('constraints'))
+
     prompt = f"""
 PHASE 2: ICP DISCOVERY & DATA PROXIES
-Based on the product features: {json.dumps(phase1_result.get('features'))}
-And constraints: {json.dumps(phase1_result.get('constraints'))}
+Based on the product features: {features_json}
+And constraints: {constraints_json}
 
 Output JSON format ONLY:
 {{
@@ -211,8 +217,8 @@ Output JSON format ONLY:
 }}
 """ if lang == 'en' else f"""
 PHASE 2: ICP DISCOVERY & DATA PROXIES
-Basierend auf Features: {json.dumps(phase1_result.get('features'))}
-Und Constraints: {json.dumps(phase1_result.get('constraints'))}
+Basierend auf Features: {features_json}
+Und Constraints: {constraints_json}
 
 Output JSON format ONLY:
 {{
@@ -222,17 +228,18 @@ Output JSON format ONLY:
 """
     # Fix: Prepend system instruction manually
     full_prompt = sys_instr + "\n\n" + prompt
-    response = call_openai_chat(full_prompt, json_mode=True)
+    response = call_openai_chat(full_prompt, response_format_json=True)
     print(response)
 
 def hunt_whales(data):
     phase2_result = data.get('phase2Result')
     lang = data.get('language', 'de')
     sys_instr = get_system_instruction(lang)
-    prompt = f"PHASE 3: WHALE HUNTING for {json.dumps(phase2_result.get('icps'))}. Identify 3-5 concrete DACH companies per industry and buying center roles. Output JSON ONLY."
+    icps_json = json.dumps(phase2_result.get('icps'))
+    prompt = f"PHASE 3: WHALE HUNTING for {icps_json}. Identify 3-5 concrete DACH companies per industry and buying center roles. Output JSON ONLY."
     # Fix: Prepend system instruction manually
     full_prompt = sys_instr + "\n\n" + prompt
-    response = call_openai_chat(full_prompt, json_mode=True)
+    response = call_openai_chat(full_prompt, response_format_json=True)
     print(response)
 
 def develop_strategy(data):
@@ -240,16 +247,18 @@ def develop_strategy(data):
     phase1_result = data.get('phase1Result')
     lang = data.get('language', 'de')
     sys_instr = get_system_instruction(lang)
-    prompt = f"PHASE 4: STRATEGY Matrix for {json.dumps(phase3_result)}. Apply Hybrid logic. Output JSON ONLY."
+    phase3_json = json.dumps(phase3_result)
+    prompt = f"PHASE 4: STRATEGY Matrix for {phase3_json}. Apply Hybrid logic. Output JSON ONLY."
     # Fix: Prepend system instruction manually
     full_prompt = sys_instr + "\n\n" + prompt
-    response = call_openai_chat(full_prompt, json_mode=True)
+    response = call_openai_chat(full_prompt, response_format_json=True)
     print(response)
 
 def generate_assets(data):
     lang = data.get('language', 'de')
     sys_instr = get_system_instruction(lang)
-    prompt = f"PHASE 5: GTM STRATEGY REPORT Markdown. Use facts, TCO, ROI. Data: {json.dumps(data)}"
+    data_json = json.dumps(data)
+    prompt = f"PHASE 5: GTM STRATEGY REPORT Markdown. Use facts, TCO, ROI. Data: {data_json}"
     # Fix: Prepend system instruction manually
     full_prompt = sys_instr + "\n\n" + prompt
     response = call_openai_chat(full_prompt)
@@ -258,10 +267,11 @@ def generate_assets(data):
 def generate_sales_enablement(data):
     lang = data.get('language', 'de')
     sys_instr = get_system_instruction(lang)
-    prompt = f"PHASE 6: Battlecards and MJ Prompts. Data: {json.dumps(data)}. Output JSON ONLY."
+    data_json = json.dumps(data)
+    prompt = f"PHASE 6: Battlecards and MJ Prompts. Data: {data_json}. Output JSON ONLY."
     # Fix: Prepend system instruction manually
     full_prompt = sys_instr + "\n\n" + prompt
-    response = call_openai_chat(full_prompt, json_mode=True)
+    response = call_openai_chat(full_prompt, response_format_json=True)
     print(response)
 
 def main():
@@ -296,4 +306,4 @@ def main():
         print(json.dumps({"error": f"Unknown mode: {args.mode}"}))
 
 if __name__ == "__main__":
-    main()
+    main()
\ No newline at end of file