feat(chat): openai-chat 协议按 (provider, upstream-model) 维度透传供应商私有 JSON 字段（extra_body）

config.example.yml

@@ -215,6 +215,24 @@ providers:
           output_price: 15
           cache_write_price: 3.75
           cache_read_price: 0.30
+  # Example: per-(provider, upstream-model) extra_body for vendor-specific
+  # switches that are not part of the OpenAI Chat Completions schema. Only
+  # honored on the openai-chat protocol dispatch path; the configured map is
+  # merged into the top-level JSON of each outbound request to that specific
+  # offer. Standard fields (model/messages/stream/...) take precedence and
+  # cannot be clobbered. Sibling offers on the same provider are unaffected.
+  #
+  # qwen-dashscope:
+  #   base_url: "https://dashscope.aliyuncs.com/compatible-mode/v1"
+  #   api_key: "replace-with-dashscope-api-key"
+  #   protocol: openai-chat
+  #   offers:
+  #     - model: qwen3-plus
+  #       overrides:
+  #         extra_body:
+  #           enable_search: true
+  #     - model: deepseek-v4-pro
+  #       # No overrides.extra_body → no vendor switches injected.
 
 routes:
     # Optional aliases. Provider models are listed directly in the Codex catalog

docs/CONFIGURATION.md

@@ -105,6 +105,10 @@ providers:
           output_price: 8
           cache_write_price: 1
           cache_read_price: 0.25
+        overrides:
+          # 供应商私有顶层 JSON 字段（仅 openai-chat 协议）。作用域为当前 offer。
+          extra_body:
+            enable_search: true
 ```
 
 ### Protocol 类型

internal/config/config.go

@@ -168,6 +168,12 @@ type ModelMeta struct {
 	// WebSearch holds model-level web search config (overrides provider-level).
 	WebSearch  WebSearchConfig
 	Extensions map[string]ExtensionSettings
+	// ExtraBody carries vendor-specific top-level JSON switches that the
+	// openai-chat protocol dispatcher merges into the outbound Chat Completions
+	// request body (e.g. {"enable_search": true} for Qwen/DashScope). Scoped
+	// per (provider, upstream-model) tuple — sourced from
+	// providers.<key>.offers[].overrides.extra_body in YAML.
+	ExtraBody map[string]any
 }
 
 // ModelPricing holds per-provider model pricing.
@@ -200,6 +206,12 @@ type ModelDef struct {
 	SupportsImageDetailOriginal bool
 	WebSearch                   WebSearchConfig
 	Extensions                  map[string]ExtensionSettings
+	// ExtraBody carries vendor-specific top-level JSON switches. On ModelDef
+	// it exists only as the intermediate type used by the offer-override merge
+	// pipeline; it is not exposed at the top-level `models:` YAML segment.
+	// Final propagation target is ModelMeta.ExtraBody, populated per
+	// (provider, upstream-model) tuple via providers.<key>.offers[].overrides.extra_body.
+	ExtraBody map[string]any
 }
 
 // OfferEntry declares that a provider offers a model defined in Models.

internal/config/config_loader.go

@@ -119,6 +119,7 @@ type ModelDefFileConfig struct {
 	SupportsImageDetailOriginal *bool                            `yaml:"supports_image_detail_original,omitempty" json:"supports_image_detail_original,omitempty"`
 	WebSearch                   WebSearchFileConfig              `yaml:"web_search,omitempty" json:"web_search,omitempty"`
 	Extensions                  map[string]ExtensionFileConfig   `yaml:"extensions,omitempty" json:"extensions,omitempty"`
+	ExtraBody                   map[string]any                   `yaml:"extra_body,omitempty" json:"extra_body,omitempty"`
 }
 
 type OfferFileConfig struct {
@@ -611,6 +612,9 @@ func mergeModelDefOverrides(base ModelDef, override ModelDefFileConfig) ModelDef
 			}
 		}
 	}
+	if len(override.ExtraBody) > 0 {
+		out.ExtraBody = cloneAnyMap(override.ExtraBody)
+	}
 	return out
 }
 
@@ -651,6 +655,9 @@ func applyModelOverrides(meta *ModelMeta, override ModelDef) {
 	if override.SupportsImageDetailOriginal {
 		meta.SupportsImageDetailOriginal = true
 	}
+	if len(override.ExtraBody) > 0 {
+		meta.ExtraBody = cloneAnyMap(override.ExtraBody)
+	}
 }
 
 // buildRoutes parses route specs and merges model metadata.

internal/config/config_test.go

@@ -1074,3 +1074,79 @@ routes:
 		t.Fatalf("DisplayName = %q, want \"My Custom Display Name\"", route.DisplayName)
 	}
 }
+
+// TestLoadFromYAMLParsesOfferExtraBody verifies that vendor-specific top-level
+// JSON switches written under providers.<key>.offers[].overrides.extra_body are
+// propagated to the corresponding ModelMeta in cfg.ProviderDefs[provider].Models[upstream].
+//
+// This is the (provider, upstream-model) tuple granularity: two different offers
+// on the same provider, and the same model name offered by two different providers,
+// each carry independent ExtraBody maps.
+func TestLoadFromYAMLParsesOfferExtraBody(t *testing.T) {
+	cfg, err := config.LoadFromYAML([]byte(`
+mode: Transform
+models:
+  qwen3-plus:
+    context_window: 1000000
+  deepseek-v4-pro:
+    context_window: 1000000
+providers:
+  aliyun:
+    base_url: https://dashscope.aliyuncs.com/compatible-mode/v1
+    api_key: aliyun-key
+    protocol: openai-chat
+    offers:
+      - model: qwen3-plus
+        overrides:
+          extra_body:
+            enable_search: true
+            extra_flag: 1
+      - model: deepseek-v4-pro
+  bailian:
+    base_url: https://bailian.example.test/v1
+    api_key: bailian-key
+    protocol: openai-chat
+    offers:
+      - model: qwen3-plus
+        overrides:
+          extra_body:
+            enable_search: false
+routes:
+  qwen:
+    model: qwen3-plus
+    provider: aliyun
+`))
+	if err != nil {
+		t.Fatalf("LoadFromYAML() error = %v", err)
+	}
+
+	aliyunQwen, ok := cfg.ProviderDefs["aliyun"].Models["qwen3-plus"]
+	if !ok {
+		t.Fatalf("ProviderDefs[aliyun].Models[qwen3-plus] missing")
+	}
+	if aliyunQwen.ExtraBody["enable_search"] != true {
+		t.Errorf("aliyun/qwen3-plus ExtraBody[enable_search] = %v, want true", aliyunQwen.ExtraBody["enable_search"])
+	}
+	if aliyunQwen.ExtraBody["extra_flag"] != 1 {
+		t.Errorf("aliyun/qwen3-plus ExtraBody[extra_flag] = %v, want 1", aliyunQwen.ExtraBody["extra_flag"])
+	}
+
+	aliyunDeepseek, ok := cfg.ProviderDefs["aliyun"].Models["deepseek-v4-pro"]
+	if !ok {
+		t.Fatalf("ProviderDefs[aliyun].Models[deepseek-v4-pro] missing")
+	}
+	if len(aliyunDeepseek.ExtraBody) != 0 {
+		t.Errorf("aliyun/deepseek-v4-pro ExtraBody = %+v, want empty when no overrides.extra_body is set", aliyunDeepseek.ExtraBody)
+	}
+
+	bailianQwen, ok := cfg.ProviderDefs["bailian"].Models["qwen3-plus"]
+	if !ok {
+		t.Fatalf("ProviderDefs[bailian].Models[qwen3-plus] missing")
+	}
+	if bailianQwen.ExtraBody["enable_search"] != false {
+		t.Errorf("bailian/qwen3-plus ExtraBody[enable_search] = %v, want false (independent from aliyun's same-name offer)", bailianQwen.ExtraBody["enable_search"])
+	}
+	if _, hasExtraFlag := bailianQwen.ExtraBody["extra_flag"]; hasExtraFlag {
+		t.Errorf("bailian/qwen3-plus should not carry aliyun's extra_flag key — per-(provider, model) isolation broken")
+	}
+}

internal/config/convert.go

@@ -134,6 +134,10 @@ func toModelDefFileConfig(def ModelDef) ModelDefFileConfig {
 		}
 	}
 
+	if len(def.ExtraBody) > 0 {
+		m.ExtraBody = cloneAnyMap(def.ExtraBody)
+	}
+
 	return m
 }
 

internal/protocol/chat/adapter.go

@@ -138,9 +138,29 @@ func (a *ChatProviderAdapter) FromCoreRequest(ctx context.Context, req *format.C
 		}
 	}
 
+	// extra_body: vendor-specific top-level JSON switches (e.g. enable_search)
+	// sourced from CoreRequest.Extensions["openai_chat"]["extra_body"].
+	// The dispatcher writes this value once per request based on the resolved
+	// (provider, upstream-model) tuple. ChatRequest.MarshalJSON flattens it to
+	// the top-level JSON object of the outbound body.
+	if extra := extractChatExtraBody(req.Extensions); len(extra) > 0 {
+		chatReq.ExtraParams = extra
+	}
+
 	return chatReq, nil
 }
 
+// extractChatExtraBody returns the openai-chat extra_body map carried on a
+// CoreRequest, or nil when the key is absent or has the wrong shape.
+func extractChatExtraBody(ext map[string]any) map[string]any {
+	bag, ok := ext["openai_chat"].(map[string]any)
+	if !ok {
+		return nil
+	}
+	extra, _ := bag["extra_body"].(map[string]any)
+	return extra
+}
+
 // =========================================================================
 // ToCoreResponse — *ChatResponse → *CoreResponse
 // =========================================================================