ai-agent-book 精选快照（<2MB 代码与文档，来自 github.com/bojieli/ai-agent-book）

chapter8/premature-completion-dpo/llm_client.py

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+"""OpenAI 兼容 API 客户端与证据回执工具（真实 LLM 路径专用）。
+
+约定与 chapter8/self-modifying-agent/llm_generator.py 一致：
+原始请求、原始响应、token 用量、延迟、请求/响应哈希都进入证据回执；
+validation/<run>/evidence.json 保存完整证据，validation/latest.json 指向最近一次。
+"""
+
+from __future__ import annotations
+
+import hashlib
+import json
+import os
+import time
+from pathlib import Path
+from typing import Any
+
+from openai import OpenAI
+
+ROOT = Path(__file__).resolve().parent
+
+PROVIDER_DEFAULTS = {
+    "openai": ("OPENAI_API_KEY", None, "gpt-4o-mini"),
+    "ark": ("ARK_API_KEY", "https://ark.cn-beijing.volces.com/api/v3", None),
+    "openrouter": ("OPENROUTER_API_KEY", "https://openrouter.ai/api/v1", "openai/gpt-4o-mini"),
+}
+
+
+def make_client(provider: str) -> tuple[OpenAI, dict[str, Any]]:
+    """按供应商创建 OpenAI 兼容客户端，返回客户端与不含凭据的后端元数据。"""
+    if provider not in PROVIDER_DEFAULTS:
+        raise ValueError(f"不支持的 provider: {provider}（可选 openai/ark/openrouter）")
+    env_name, base_url, _ = PROVIDER_DEFAULTS[provider]
+    key = os.getenv(env_name)
+    if not key:
+        raise RuntimeError(f"需要设置环境变量 {env_name}")
+    client = OpenAI(api_key=key, base_url=base_url) if base_url else OpenAI(api_key=key)
+    backend = {
+        "provider": provider,
+        "endpoint": (base_url or "https://api.openai.com/v1") + "/chat/completions",
+        "credential_env": env_name,
+        "credential_value_recorded": False,
+    }
+    return client, backend
+
+
+def default_model(provider: str) -> str:
+    if provider == "ark":
+        return os.getenv("ARK_MODEL", "doubao-seed-1-6-250615")
+    return PROVIDER_DEFAULTS[provider][2] or "gpt-4o-mini"
+
+
+def chat_with_receipt(
+    client: OpenAI,
+    backend: dict[str, Any],
+    request: dict[str, Any],
+) -> tuple[str, dict[str, Any]]:
+    """发起一次 Chat Completions 调用，返回（文本内容, 证据回执）。"""
+    started = time.perf_counter()
+    response = client.chat.completions.create(**request)
+    elapsed = time.perf_counter() - started
+    raw = response.model_dump(mode="json", exclude_none=True)
+    usage = raw.get("usage") or {}
+    receipt = {
+        "backend": {**backend, "model": request.get("model")},
+        "request": request,
+        "response": raw,
+        "request_sha256": hashlib.sha256(
+            json.dumps(request, sort_keys=True, ensure_ascii=False).encode()
+        ).hexdigest(),
+        "response_sha256": hashlib.sha256(
+            json.dumps(raw, sort_keys=True, ensure_ascii=False).encode()
+        ).hexdigest(),
+        "elapsed_seconds": round(elapsed, 6),
+        "usage": {
+            "prompt_tokens": int(usage.get("prompt_tokens") or 0),
+            "completion_tokens": int(usage.get("completion_tokens") or 0),
+            "total_tokens": int(usage.get("total_tokens") or 0),
+        },
+    }
+    return (response.choices[0].message.content or ""), receipt
+
+
+def save_evidence(run: str, receipts: list[dict[str, Any]], extra: dict[str, Any] | None = None) -> Path:
+    """把一轮真实调用的全部回执写入 validation/<run>/evidence.json 并更新 latest.json。"""
+    run_dir = ROOT / "validation" / run
+    run_dir.mkdir(parents=True, exist_ok=True)
+    evidence = {
+        "experiment": "8-17 premature-completion-dpo",
+        "run": run,
+        "receipt_count": len(receipts),
+        "receipts": receipts,
+        "extra": extra or {},
+    }
+    path = run_dir / "evidence.json"
+    path.write_text(json.dumps(evidence, ensure_ascii=False, indent=2), encoding="utf-8")
+    latest = ROOT / "validation" / "latest.json"
+    latest.write_text(json.dumps({"run": run, "evidence": str(path.relative_to(ROOT))},
+                                 ensure_ascii=False, indent=2), encoding="utf-8")
+    return path