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模型選擇

選擇合適的模型會大幅影響成本與品質。

依任務類型的建議

任務建議模型原因
簡單問答gpt-5-mini, gemini-2.5-flash快速、便宜、已足夠應付需求
複雜推理gpt-5.4, claude-opus-4-6, deepseek-r1邏輯與規劃能力更佳
程式撰寫claude-sonnet-4-6, gpt-4o, deepseek-v3.2針對程式碼進行最佳化
創意寫作claude-sonnet-4-6, gpt-4o文字表達品質更佳
視覺/影像gpt-4o, claude-sonnet-4-6, gemini-2.5-flash原生支援視覺能力
長上下文gemini-2.5-pro, claude-sonnet-4-61M+ token 視窗
成本敏感gpt-5-mini, gemini-2.5-flash, deepseek-v3.2最佳性價比

成本層級

$$$$ Premium: gpt-5.4, claude-opus-4-6
$$$  Standard: claude-sonnet-4-6, gpt-4o
$$   Budget:   gpt-5-mini, gemini-2.5-flash
$    Economy:  deepseek-v3.2, deepseek-r1

成本最佳化

1. 優先使用較小型的模型

def smart_query(question: str, complexity: str = "auto"):
    """Use cheaper models for simple tasks."""

    if complexity == "simple":
        model = "gpt-5-mini"
    elif complexity == "complex":
        model = "gpt-4o"
    else:
        # Start cheap, escalate if needed
        model = "gpt-5-mini"

    response = client.chat.completions.create(
        model=model,
        messages=[{"role": "user", "content": question}]
    )
    return response

2. 設定 max_tokens

請務必設定合理的 max_tokens 上限:
# ❌ Bad: No limit, could generate thousands of tokens
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Summarize this article"}]
)

# ✅ Good: Limit response length
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Summarize this article"}],
    max_tokens=500  # Reasonable limit for a summary
)

3. 最佳化 Prompt

# ❌ Verbose prompt (more input tokens)
prompt = """
I would like you to please help me by analyzing the following text
and providing a comprehensive summary of the main points. Please be
thorough but also concise in your response. The text is as follows:
{text}
"""

# ✅ Concise prompt (fewer tokens)
prompt = "Summarize the key points:\n{text}"

4. 啟用快取

善用語意快取
# For repeated similar queries, caching provides major savings
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "What is machine learning?"}],
    temperature=0  # Deterministic = better cache hits
)

5. 批次處理相似請求

# ❌ Many small requests
for question in questions:
    response = client.chat.completions.create(
        model="gpt-4o",
        messages=[{"role": "user", "content": question}]
    )

# ✅ Fewer larger requests
combined_prompt = "\n".join([f"{i+1}. {q}" for i, q in enumerate(questions)])
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": f"Answer each question:\n{combined_prompt}"}]
)

效能最佳化

1. 為 UX 使用串流回應

串流回應可改善使用者感受到的效能:
stream = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Write a long essay"}],
    stream=True
)

for chunk in stream:
    if chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)

2. 互動式使用情境選擇快速模型

使用情境建議延遲
聊天 UIgpt-5-mini, gemini-2.5-flash~200ms 首個 token
Tab 補全claude-haiku-4-5~150ms 首個 token
背景處理gpt-4o, claude-sonnet-4-6~500ms 首個 token

3. 設定逾時

client = OpenAI(
    api_key="sk-your-key",
    base_url="https://api.lemondata.cc/v1",
    timeout=60.0  # 60 second timeout
)

可靠性

1. 實作重試機制

import time
from openai import RateLimitError, APIError

def chat_with_retry(messages, max_retries=3):
    for attempt in range(max_retries):
        try:
            return client.chat.completions.create(
                model="gpt-4o",
                messages=messages
            )
        except RateLimitError:
            wait = 2 ** attempt
            print(f"Rate limited, waiting {wait}s...")
            time.sleep(wait)
        except APIError as e:
            if attempt == max_retries - 1:
                raise
            time.sleep(1)
    raise Exception("Max retries exceeded")

2. 妥善處理錯誤

from openai import APIError, AuthenticationError, RateLimitError

try:
    response = client.chat.completions.create(...)
except AuthenticationError:
    # Check API key
    notify_admin("Invalid API key")
except RateLimitError:
    # Queue for later or use backup
    add_to_queue(request)
except APIError as e:
    if e.status_code == 402:
        notify_admin("Balance low")
    elif e.status_code >= 500:
        # Server error, retry later
        schedule_retry(request)

3. 使用備援模型

FALLBACK_CHAIN = ["gpt-4o", "claude-sonnet-4-6", "gemini-2.5-flash"]

def chat_with_fallback(messages):
    for model in FALLBACK_CHAIN:
        try:
            return client.chat.completions.create(
                model=model,
                messages=messages
            )
        except APIError:
            continue
    raise Exception("All models failed")

安全性

1. 保護 API Keys

# ❌ Never hardcode keys
client = OpenAI(api_key="sk-abc123...")

# ✅ Use environment variables
import os
client = OpenAI(api_key=os.environ["LEMONDATA_API_KEY"])

2. 驗證使用者輸入

def validate_message(content: str) -> bool:
    """Validate user input before sending to API."""
    if len(content) > 100000:
        raise ValueError("Message too long")
    # Add other validation as needed
    return True

3. 設定 API Key 限制

為以下用途建立具備支出上限的獨立 API keys:
  • 開發/測試
  • 正式環境
  • 不同應用程式

監控

1. 追蹤使用量

請定期檢查您的 dashboard,以掌握:
  • 各模型的 token 使用量
  • 成本明細
  • 快取命中率
  • 錯誤率

2. 記錄重要指標

import logging

response = client.chat.completions.create(...)

logging.info({
    "model": response.model,
    "prompt_tokens": response.usage.prompt_tokens,
    "completion_tokens": response.usage.completion_tokens,
    "total_tokens": response.usage.total_tokens,
})

3. 設定警示

在您的 dashboard 中設定低餘額警示,以避免服務中斷。

檢查清單

  • 為每項任務使用適當的模型
  • 設定 max_tokens 上限
  • Prompt 保持精簡
  • 在適當情況下啟用快取
  • 批次處理相似請求
  • 為互動式 UX 使用串流回應
  • 即時使用情境採用快速模型
  • 已設定逾時
  • 已實作重試邏輯
  • 已建立錯誤處理機制
  • 已設定備援模型
  • API keys 存放於環境變數中
  • 輸入驗證
  • 為 dev/prod 使用獨立 keys
  • 已設定支出上限