feat(body-rules): 支持按 provider_type 覆盖 cache-sensitive 保护字段集合

Codex 通过 OpenAI CLI/Compact 格式转发时，endpoint body_rules 需要能
修改 instructions/input/tools 等 prompt 字段。新增 provider_type 维度的
保护集合映射，Codex 场景仅保护 prompt_cache_key，其余 prompt 字段交由
body_rules 自由调整。

src/api/handlers/base/chat_handler_base.py

@@ -846,7 +846,10 @@ class ChatHandlerBase(BaseMessageHandler, ABC):
             mapped_model=mapped_model,
             envelope=envelope,
             extra_headers=extra_headers,
-            protected_body_keys=get_cache_sensitive_protected_body_keys(provider_api_format),
+            protected_body_keys=get_cache_sensitive_protected_body_keys(
+                provider_api_format,
+                provider_type=provider_type,
+            ),
             upstream_is_stream=upstream_is_stream,
             needs_conversion=needs_conversion,
             provider_api_format=provider_api_format,

src/api/handlers/base/cli_stream_mixin.py

@@ -442,7 +442,10 @@ class CliStreamMixin:
             extra_headers=extra_headers if extra_headers else None,
             pre_computed_auth=auth_info.as_tuple() if auth_info else None,
             envelope=envelope,
-            protected_body_keys=get_cache_sensitive_protected_body_keys(provider_api_format),
+            protected_body_keys=get_cache_sensitive_protected_body_keys(
+                provider_api_format,
+                provider_type=provider_type,
+            ),
             provider_api_format=provider_api_format,
         )
         if upstream_is_stream:

src/api/handlers/base/cli_sync_mixin.py

@@ -263,7 +263,10 @@ class CliSyncMixin:
                 extra_headers=extra_headers if extra_headers else None,
                 pre_computed_auth=auth_info.as_tuple() if auth_info else None,
                 envelope=envelope,
-                protected_body_keys=get_cache_sensitive_protected_body_keys(provider_api_format),
+                protected_body_keys=get_cache_sensitive_protected_body_keys(
+                    provider_api_format,
+                    provider_type=provider_type,
+                ),
                 provider_api_format=provider_api_format,
             )
             if upstream_is_stream:

src/api/handlers/base/handler_adapter_base.py

@@ -514,7 +514,10 @@ class HandlerAdapterBase(ApiAdapter):
             body = apply_body_rules(
                 body,
                 body_rules,
-                protected_keys=get_cache_sensitive_protected_body_keys(cls.FORMAT_ID),
+                protected_keys=get_cache_sensitive_protected_body_keys(
+                    cls.FORMAT_ID,
+                    provider_type=provider_type,
+                ),
                 original_body=body,
             )
 

src/api/handlers/base/request_builder.py

@@ -129,11 +129,27 @@ _CACHE_SENSITIVE_BODY_FIELDS_BY_FORMAT: dict[str, frozenset[str]] = {
     ),
 }
 
+# Provider 维度可覆盖默认 prompt-bearing 保护集合。
+# Codex OpenAI CLI/Compact 允许 endpoint body_rules 调整 instructions/input/tools/tool_choice，
+# 仅继续保护系统字段与 prompt_cache_key，避免"已保存但规则不生效"。
+_CODEX_PROTECTED: frozenset[str] = frozenset({"prompt_cache_key"})
+_CACHE_SENSITIVE_BODY_FIELDS_BY_PROVIDER_AND_FORMAT: dict[tuple[str, str], frozenset[str]] = {
+    ("codex", "openai:cli"): _CODEX_PROTECTED,
+    ("codex", "openai:compact"): _CODEX_PROTECTED,
+}
 
-def get_cache_sensitive_protected_body_keys(provider_api_format: str | None) -> frozenset[str]:
-    """根据目标 Provider API 格式返回需要保护的顶层请求字段。"""
+
+def get_cache_sensitive_protected_body_keys(
+    provider_api_format: str | None,
+    *,
+    provider_type: str | None = None,
+) -> frozenset[str]:
+    """根据目标 Provider API 格式和 provider_type 返回需要保护的顶层请求字段。"""
     fmt = str(provider_api_format or "").strip().lower()
-    extra = _CACHE_SENSITIVE_BODY_FIELDS_BY_FORMAT.get(fmt, frozenset())
+    pt = str(provider_type or "").strip().lower()
+    extra = _CACHE_SENSITIVE_BODY_FIELDS_BY_PROVIDER_AND_FORMAT.get((pt, fmt))
+    if extra is None:
+        extra = _CACHE_SENSITIVE_BODY_FIELDS_BY_FORMAT.get(fmt, frozenset())
     if not extra:
         return PROTECTED_BODY_FIELDS
     return frozenset({*PROTECTED_BODY_FIELDS, *extra})

tests/services/test_codex_request.py

@@ -279,6 +279,37 @@ def test_codex_passthrough_builder_preserves_real_codex_headers() -> None:
     assert "x-forwarded-scheme" not in headers
 
 
+def test_codex_passthrough_builder_applies_prompt_body_rules() -> None:
+    from src.api.handlers.base.request_builder import get_cache_sensitive_protected_body_keys
+    from src.core.api_format.metadata import CODEX_DEFAULT_BODY_RULES
+
+    builder = PassthroughRequestBuilder()
+    endpoint = SimpleNamespace(
+        api_family="openai",
+        endpoint_kind="cli",
+        header_rules=None,
+        body_rules=list(CODEX_DEFAULT_BODY_RULES),
+    )
+    key = SimpleNamespace(api_key="unused")
+
+    payload, _headers = builder.build(
+        {"model": "gpt-test", "input": []},
+        {"content-type": "application/json"},
+        endpoint,
+        key,
+        pre_computed_auth=("Authorization", "Bearer upstream-token"),
+        protected_body_keys=get_cache_sensitive_protected_body_keys(
+            "openai:cli",
+            provider_type="codex",
+        ),
+        provider_api_format="openai:cli",
+    )
+
+    assert payload["instructions"] == "You are GPT-5."
+    assert payload["store"] is False
+    assert "max_output_tokens" not in payload
+
+
 def _encode_unsigned_jwt(payload: dict[str, object]) -> str:
     token = jwt.encode(payload, key="", algorithm="none")
     return token.decode("utf-8") if isinstance(token, bytes) else token

tests/unit/test_body_rules.py

@@ -1532,6 +1532,14 @@ class TestProtectedBodyKeys:
                 "prompt_cache_key",
             }
         )
+        assert get_cache_sensitive_protected_body_keys(
+            "openai:cli",
+            provider_type="codex",
+        ) == frozenset({"model", "stream", "prompt_cache_key"})
+        assert get_cache_sensitive_protected_body_keys(
+            "openai:compact",
+            provider_type="codex",
+        ) == frozenset({"model", "stream", "prompt_cache_key"})
         assert get_cache_sensitive_protected_body_keys("claude:chat") == frozenset(
             {"model", "stream", "messages", "system", "tools", "tool_choice"}
         )
@@ -1550,6 +1558,30 @@ class TestProtectedBodyKeys:
             }
         )
 
+    def test_codex_openai_cli_allows_body_rules_on_prompt_fields(self) -> None:
+        body = {
+            "model": "gpt-5-codex",
+            "input": [{"role": "user", "content": "hi"}],
+        }
+        protected_keys = get_cache_sensitive_protected_body_keys(
+            "openai:cli",
+            provider_type="codex",
+        )
+
+        result = apply_body_rules(
+            body,
+            [
+                {"action": "set", "path": "instructions", "value": "You are GPT-5."},
+                {"action": "set", "path": "input[0].content", "value": "patched"},
+                {"action": "set", "path": "prompt_cache_key", "value": "blocked"},
+            ],
+            protected_keys=protected_keys,
+        )
+
+        assert result["instructions"] == "You are GPT-5."
+        assert result["input"][0]["content"] == "patched"
+        assert "prompt_cache_key" not in result
+
     def test_gemini_camelcase_alias_prompt_fields_are_protected(self) -> None:
         body = {
             "contents": [{"role": "user", "parts": [{"text": "hi"}]}],