Add multi-turn Claude chatbot with streaming and prompt caching

claude_chat.py

@@ -0,0 +1,82 @@
+"""
+Multi-turn conversation chatbot using the Anthropic Claude API.
+Usage: python claude_chat.py
+Requires: pip install anthropic
+Set ANTHROPIC_API_KEY environment variable before running.
+"""
+
+import os
+import anthropic
+
+SYSTEM_PROMPT = """You are a helpful AI assistant with expertise in Python and data science.
+You help the user understand their code, debug issues, and learn new concepts.
+Be concise, clear, and provide working code examples when relevant."""
+
+MODEL = "claude-opus-4-7"
+
+
+def chat():
+    client = anthropic.Anthropic(api_key=os.environ.get("ANTHROPIC_API_KEY"))
+    messages = []
+
+    print("Claude Chat — tapez 'quit' ou 'exit' pour quitter, 'reset' pour effacer l'historique.")
+    print("-" * 60)
+
+    while True:
+        try:
+            user_input = input("\nVous: ").strip()
+        except (EOFError, KeyboardInterrupt):
+            print("\nAu revoir!")
+            break
+
+        if not user_input:
+            continue
+
+        if user_input.lower() in ("quit", "exit"):
+            print("Au revoir!")
+            break
+
+        if user_input.lower() == "reset":
+            messages = []
+            print("Historique effacé.")
+            continue
+
+        messages.append({"role": "user", "content": user_input})
+
+        print("\nClaude: ", end="", flush=True)
+
+        with client.messages.stream(
+            model=MODEL,
+            max_tokens=4096,
+            thinking={"type": "adaptive"},
+            system=[
+                {
+                    "type": "text",
+                    "text": SYSTEM_PROMPT,
+                    "cache_control": {"type": "ephemeral"},
+                }
+            ],
+            messages=messages,
+        ) as stream:
+            response_text = ""
+            for event in stream:
+                if event.type == "content_block_delta":
+                    if event.delta.type == "text_delta":
+                        print(event.delta.text, end="", flush=True)
+                        response_text += event.delta.text
+
+        print()
+        messages.append({"role": "assistant", "content": response_text})
+
+        final = stream.get_final_message()
+        usage = final.usage
+        cache_read = getattr(usage, "cache_read_input_tokens", 0) or 0
+        if cache_read:
+            print(f"  [tokens: in={usage.input_tokens}, out={usage.output_tokens}, cache_hit={cache_read}]")
+
+
+if __name__ == "__main__":
+    if not os.environ.get("ANTHROPIC_API_KEY"):
+        print("Erreur: définissez la variable d'environnement ANTHROPIC_API_KEY")
+        raise SystemExit(1)
+    chat()