停止理由とフォールバック

client = anthropic.Anthropic()

response = client.messages.create(
    model="claude-opus-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello!"}],
)
if response.stop_reason == "end_turn":
    # 完全なレスポンスを処理します
    for block in response.content:
        if block.type == "text":
            print(block.text)

client = anthropic.Anthropic()
# トークン数を制限したリクエスト
response = client.messages.create(
    model="claude-opus-5",
    max_tokens=10,
    messages=[{"role": "user", "content": "Explain quantum physics"}],
)

if response.stop_reason == "max_tokens":
    # レスポンスが途中で打ち切られました
    print("Response was cut off at token limit")
    # 続きを取得するには再度リクエストすることを検討してください

client = anthropic.Anthropic()
response = client.messages.create(
    model="claude-opus-5",
    max_tokens=1024,
    stop_sequences=["END", "STOP"],
    messages=[{"role": "user", "content": "Generate text until you say END"}],
)

if response.stop_reason == "stop_sequence":
    print(f"Stopped at sequence: {response.stop_sequence}")

client = anthropic.Anthropic()
weather_tool = {
    "name": "get_weather",
    "description": "Get the current weather in a given location",
    "input_schema": {
        "type": "object",
        "properties": {
            "location": {"type": "string", "description": "City and state"},
        },
        "required": ["location"],
    },
}


def execute_tool(name, tool_input):
    """Execute a tool and return the result."""
    return f"Weather in {tool_input.get('location', 'unknown')}: 72°F"


response = client.messages.create(
    model="claude-opus-5",
    max_tokens=1024,
    tools=[weather_tool],
    messages=[{"role": "user", "content": "What is the weather in San Francisco?"}],
)

if response.stop_reason == "tool_use":
    # ツールを抽出して実行する
    for block in response.content:
        if block.type == "tool_use":
            result = execute_tool(block.name, block.input)
            # 最終応答のために結果をClaudeに返す

response = client.messages.create(
    model="claude-opus-5",
    max_tokens=4096,
    tools=[{"type": "web_search_20250305", "name": "web_search"}],
    messages=[{"role": "user", "content": "Search for latest AI news"}],
)

if response.stop_reason == "pause_turn":
    # レスポンスを送り返して会話を続けます
    messages = [
        {"role": "user", "content": "Search for latest AI news"},
        {"role": "assistant", "content": response.content},
    ]
    continuation = client.messages.create(
        model="claude-opus-5",
        max_tokens=4096,
        messages=messages,
        tools=[{"type": "web_search_20250305", "name": "web_search"}],
    )

client = anthropic.Anthropic()
response = client.messages.create(
    model="claude-opus-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "[Unsafe request]"}],
)

if response.stop_reason == "refusal":
    # Claudeが応答を拒否しました
    print("Claude was unable to process this request")
    # リクエストの言い換えや修正を検討してください

# できるだけ多く取得するために最大トークン数でリクエスト
response = client.beta.messages.create(
    model="claude-opus-5",
    max_tokens=20000,  # Python SDK requires streaming for max_tokens above ~21k
    messages=[
        {"role": "user", "content": "Large input that uses most of context window..."}
    ],
)

if response.stop_reason == "model_context_window_exceeded":
    # レスポンスがmax_tokensより先にコンテキストウィンドウの上限に到達
    print("Response reached model's context window limit")
    # レスポンスは有効ですが、コンテキストウィンドウにより制限されました

def handle_response(response):
    if response.stop_reason == "tool_use":
        return handle_tool_use(response)
    elif response.stop_reason == "max_tokens":
        return handle_truncation(response)
    elif response.stop_reason == "model_context_window_exceeded":
        return handle_context_limit(response)
    elif response.stop_reason == "pause_turn":
        return handle_pause(response)
    elif response.stop_reason == "refusal":
        return handle_refusal(response)
    else:
        # end_turnやその他のケースを処理
        return next(
            (block.text for block in response.content if block.type == "text"), ""
        )

def handle_truncated_response(response):
    text = next((block.text for block in response.content if block.type == "text"), "")
    if response.stop_reason in ["max_tokens", "model_context_window_exceeded"]:
        if response.stop_reason == "max_tokens":
            note = "[Response truncated due to max_tokens limit]"
        else:
            note = "[Response truncated due to context window limit]"
        return f"{text}\n\n{note}"
    return text

def handle_server_tool_conversation(client, user_query, tools, max_continuations=5):
    """
    Handle server tool conversations that may require multiple continuations.

    The server runs a sampling loop when executing server tools. If the loop
    reaches its iteration limit, the API returns pause_turn. Continue the
    conversation by sending the response back to let Claude finish.
    """
    messages = [{"role": "user", "content": user_query}]

    for _ in range(max_continuations):
        response = client.messages.create(
            model="claude-opus-5", max_tokens=4096, messages=messages, tools=tools
        )

        if response.stop_reason != "pause_turn":
            # Claudeが処理を完了 - 最終レスポンスを返す
            return response

        # pause_turn: ロールの交互順を維持するためメッセージリスト全体を置き換える
        messages = [
            {"role": "user", "content": user_query},
            {"role": "assistant", "content": response.content},
        ]

    # 最大継続回数に到達 - 最後のレスポンスを返す
    return response

client = anthropic.Anthropic()

try:
    response = client.messages.create(
        model="claude-opus-5",
        max_tokens=1024,
        messages=[{"role": "user", "content": "Hello!"}],
    )

    # stop_reasonを含む成功レスポンスを処理
    if response.stop_reason == "max_tokens":
        print("Response was truncated")

except anthropic.APIStatusError as e:
    # 実際のエラーを処理
    if e.status_code == 429:
        print("Rate limit exceeded")
    elif e.status_code == 500:
        print("Server error")

client = anthropic.Anthropic()

with client.messages.stream(
    model="claude-opus-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello!"}],
) as stream:
    for event in stream:
        if event.type == "message_delta":
            stop_reason = event.delta.stop_reason
            if stop_reason:
                print(f"Stream ended with: {stop_reason}")

def complete_tool_workflow(client, user_query, tools):
    messages = [{"role": "user", "content": user_query}]

    while True:
        response = client.messages.create(
            model="claude-opus-5", max_tokens=1024, messages=messages, tools=tools
        )

        if response.stop_reason == "tool_use":
            # ツールを実行して続行
            tool_results = execute_tools(response.content)
            messages.append({"role": "assistant", "content": response.content})
            messages.append({"role": "user", "content": tool_results})
        else:
            # 最終レスポンス
            return response

def get_complete_response(client, prompt, max_attempts=3):
    messages = [{"role": "user", "content": prompt}]
    full_response = ""

    for _ in range(max_attempts):
        response = client.messages.create(
            model="claude-opus-5", messages=messages, max_tokens=4096
        )

        full_response += next(
            (block.text for block in response.content if block.type == "text"), ""
        )

        if response.stop_reason != "max_tokens":
            break

        # 中断した箇所から続行する
        messages = [
            {"role": "user", "content": prompt},
            {"role": "assistant", "content": full_response},
            {"role": "user", "content": "Please continue from where you left off."},
        ]

    return full_response

def get_max_possible_tokens(client, prompt):
    """
    Get as many tokens as possible within the model's context window
    without needing to calculate input token count
    """
    response = client.beta.messages.create(
        model="claude-opus-5",
        messages=[{"role": "user", "content": prompt}],
        max_tokens=20000,  # Python SDK requires streaming for max_tokens above ~21k
    )

    if response.stop_reason == "model_context_window_exceeded":
        # 入力サイズに対して可能な最大トークン数を取得
        print(
            f"Generated {response.usage.output_tokens} tokens (context limit reached)"
        )
    elif response.stop_reason == "max_tokens":
        # 要求したトークン数ちょうどを取得
        print(f"Generated {response.usage.output_tokens} tokens (max_tokens reached)")
    else:
        # 自然な完了
        print(f"Generated {response.usage.output_tokens} tokens (natural completion)")

    return next((block.text for block in response.content if block.type == "text"), "")