Merge pull request #276 from widwei/fix/anthropic-thinking-carrier

fix(anthropic): pass back thinking block for assistant turns without reasoning

internal/backend/agent/model/anthropic.go

@@ -1134,10 +1134,20 @@ func isAnthropicCacheableBlock(block map[string]any) bool {
 	}
 }
 
+// anthropicThinkingCarrier 记录请求内最近一个有 reasoning+signature 的 assistant 轮次。
+// thinking 模式下上游要求每个 assistant 轮次都回传 thinking 块；当某轮次（如 DeepSeek
+// adaptive thinking 跳过思考的 tool-call 轮次）没有 reasoning 时，用 carrier 的
+// thinking+signature 兜底，避免上游 "thinking must be passed back" 400。
+type anthropicThinkingCarrier struct {
+	reasoning string
+	signature string
+}
+
 func normalizeAnthropicProviderMessages(input []Message, thinkingEnabled bool, relocateImages bool) ([]string, []anthropicMessage, error) {
 	systemParts := make([]string, 0, len(input))
 	messages := make([]anthropicMessage, 0, len(input))
 	pendingToolResults := make([]map[string]any, 0, 2)
+	var thinkingCarrier *anthropicThinkingCarrier
 	flushToolResults := func() {
 		if len(pendingToolResults) == 0 {
 			return
@@ -1175,7 +1185,15 @@ func normalizeAnthropicProviderMessages(input []Message, thinkingEnabled bool, r
 			})
 		case "user", "assistant":
 			flushToolResults()
-			contentBlocks, err := anthropicProviderContentBlocks(message, thinkingEnabled)
+			if thinkingEnabled && role == "assistant" {
+				if reasoning := strings.TrimSpace(message.ReasoningContent); reasoning != "" {
+					thinkingCarrier = &anthropicThinkingCarrier{
+						reasoning: reasoning,
+						signature: anthropicThinkingSignature(message),
+					}
+				}
+			}
+			contentBlocks, err := anthropicProviderContentBlocks(message, thinkingEnabled, thinkingCarrier)
 			if err != nil {
 				return nil, nil, err
 			}
@@ -1284,7 +1302,7 @@ func isAnthropicImageBlock(block map[string]any) bool {
 	return strings.TrimSpace(anthropicStringField(block, "type")) == "image"
 }
 
-func anthropicProviderContentBlocks(message Message, thinkingEnabled bool) ([]map[string]any, error) {
+func anthropicProviderContentBlocks(message Message, thinkingEnabled bool, carrier *anthropicThinkingCarrier) ([]map[string]any, error) {
 	blocks, err := anthropicContentBlocks(message)
 	if err != nil {
 		return nil, err
@@ -1293,11 +1311,17 @@ func anthropicProviderContentBlocks(message Message, thinkingEnabled bool) ([]ma
 		return blocks, nil
 	}
 
+	reasoning := strings.TrimSpace(message.ReasoningContent)
+	signature := anthropicThinkingSignature(message)
+	if reasoning == "" && carrier != nil {
+		reasoning = carrier.reasoning
+		signature = carrier.signature
+	}
 	thinkingBlock := map[string]any{
 		"type":     "thinking",
-		"thinking": message.ReasoningContent,
+		"thinking": reasoning,
 	}
-	if signature := anthropicThinkingSignature(message); signature != "" {
+	if signature != "" {
 		thinkingBlock["signature"] = signature
 	}
 	return append([]map[string]any{thinkingBlock}, blocks...), nil
@@ -1381,9 +1405,6 @@ func shouldIncludeAnthropicThinkingBlock(message Message, thinkingEnabled bool)
 	if strings.TrimSpace(message.Role) != "assistant" {
 		return false
 	}
-	if strings.TrimSpace(message.ReasoningContent) == "" {
-		return false
-	}
 	return true
 }
 

internal/backend/agent/model/anthropic_thinking_carrier_test.go

@@ -0,0 +1,164 @@
+package modeladapter
+
+import (
+	"strings"
+	"testing"
+)
+
+// TestNormalizeAnthropicProviderMessagesThinkingCarrier 验证 thinking 模式下，
+// 缺少 reasoning 的 assistant 轮次（如 DeepSeek adaptive thinking 跳过思考的
+// tool-call 轮次）会用请求内最近一个 carrier 的 thinking+signature 兜底，
+// 保证每个 assistant 轮次都有 thinking 块，避免上游 "thinking must be passed
+// back to the API" 400。
+func TestNormalizeAnthropicProviderMessagesThinkingCarrier(t *testing.T) {
+	carrierToolCall := []ToolCallDescriptor{{
+		ID:   "call-2",
+		Type: "function",
+		Function: ToolCallFunctionShape{
+			Name:      "read",
+			Arguments: `{}`,
+		},
+	}}
+	input := []Message{
+		{Role: "user", Content: "hello"},
+		{Role: "assistant", Content: "let me check", ReasoningContent: "R1", ReasoningSignature: "S1"},
+		{Role: "user", Content: "tool result 1"},
+		{Role: "assistant", ToolCalls: carrierToolCall}, // 无 reasoning → 用 carrier
+		{Role: "user", Content: "tool result 2"},
+		{Role: "assistant", Content: "done", ReasoningContent: "R2", ReasoningSignature: "S2"},
+	}
+
+	_, messages, err := normalizeAnthropicProviderMessages(input, true, false)
+	if err != nil {
+		t.Fatalf("normalize: %v", err)
+	}
+	if len(messages) != 6 {
+		t.Fatalf("expected 6 messages, got %d", len(messages))
+	}
+
+	// 第 2 条（有 reasoning）应保留自己的 thinking。
+	assertAnthropicThinkingBlock(t, messages[1], "R1", "S1")
+	// 第 4 条（无 reasoning 的 tool-call 轮次）应复用 carrier 的 thinking+signature。
+	assertAnthropicThinkingBlock(t, messages[3], "R1", "S1")
+	// 第 5 条应为 tool_result 消息（合并路径不适用时，tool-call 轮次独立成消息）。
+	if role := messages[4].Role; role != "user" {
+		t.Fatalf("expected messages[4] role=user, got %s", role)
+	}
+	// 第 6 条有自己的 thinking。
+	assertAnthropicThinkingBlock(t, messages[5], "R2", "S2")
+
+	// tool-call 轮次应包含 tool_use 块。
+	hasToolUse := false
+	for _, block := range messages[3].Content {
+		if strings.TrimSpace(anthropicStringField(block, "type")) == "tool_use" {
+			hasToolUse = true
+		}
+	}
+	if !hasToolUse {
+		t.Fatal("expected tool_use block on the carrier-fallback assistant message")
+	}
+}
+
+// TestNormalizeAnthropicProviderMessagesThinkingCarrierFirstTurn 验证请求内第一条
+// assistant 轮次就缺 reasoning 且无 carrier 时，兜底输出空 thinking 块。
+func TestNormalizeAnthropicProviderMessagesThinkingCarrierFirstTurn(t *testing.T) {
+	input := []Message{
+		{Role: "user", Content: "hello"},
+		{Role: "assistant", Content: "ok"},
+	}
+
+	_, messages, err := normalizeAnthropicProviderMessages(input, true, false)
+	if err != nil {
+		t.Fatalf("normalize: %v", err)
+	}
+	if len(messages) != 2 {
+		t.Fatalf("expected 2 messages, got %d", len(messages))
+	}
+	if got := anthropicStringField(messages[1].Content[0], "type"); got != "thinking" {
+		t.Fatalf("expected first block type=thinking, got %s", got)
+	}
+	if got := anthropicStringField(messages[1].Content[0], "thinking"); got != "" {
+		t.Fatalf("expected empty fallback thinking, got %q", got)
+	}
+}
+
+// TestNormalizeAnthropicProviderMessagesThinkingDisabled 验证 thinking 关闭时
+// 不输出任何 thinking 块（回归保护）。
+func TestNormalizeAnthropicProviderMessagesThinkingDisabled(t *testing.T) {
+	input := []Message{
+		{Role: "user", Content: "hello"},
+		{Role: "assistant", Content: "ok", ReasoningContent: "R1", ReasoningSignature: "S1"},
+		{Role: "assistant", ToolCalls: []ToolCallDescriptor{{
+			ID:   "call-2",
+			Type: "function",
+			Function: ToolCallFunctionShape{
+				Name:      "read",
+				Arguments: `{}`,
+			},
+		}}},
+	}
+
+	_, messages, err := normalizeAnthropicProviderMessages(input, false, false)
+	if err != nil {
+		t.Fatalf("normalize: %v", err)
+	}
+	for index, message := range messages {
+		for _, block := range message.Content {
+			if blockType := anthropicStringField(block, "type"); blockType == "thinking" {
+				t.Fatalf("unexpected thinking block at messages[%d]", index)
+			}
+		}
+	}
+}
+
+// TestNormalizeAnthropicProviderMessagesThinkingMerge 验证有 reasoning 的纯
+// tool-call 轮次仍按既有逻辑合并进上一条 assistant 消息（thinking 去重，无回归）。
+func TestNormalizeAnthropicProviderMessagesThinkingMerge(t *testing.T) {
+	input := []Message{
+		{Role: "user", Content: "hello"},
+		{Role: "assistant", Content: "let me check", ReasoningContent: "R1", ReasoningSignature: "S1"},
+		{Role: "assistant", ToolCalls: []ToolCallDescriptor{{
+			ID:   "call-2",
+			Type: "function",
+			Function: ToolCallFunctionShape{
+				Name:      "read",
+				Arguments: `{}`,
+			},
+		}}, ReasoningContent: "R1", ReasoningSignature: "S1"},
+	}
+
+	_, messages, err := normalizeAnthropicProviderMessages(input, true, false)
+	if err != nil {
+		t.Fatalf("normalize: %v", err)
+	}
+	if len(messages) != 2 {
+		t.Fatalf("expected 2 messages (tool-call merged), got %d", len(messages))
+	}
+	assertAnthropicThinkingBlock(t, messages[1], "R1", "S1")
+	hasToolUse := false
+	for _, block := range messages[1].Content {
+		if blockType := anthropicStringField(block, "type"); blockType == "tool_use" {
+			hasToolUse = true
+		}
+	}
+	if !hasToolUse {
+		t.Fatal("expected merged tool_use block on messages[1]")
+	}
+}
+
+func assertAnthropicThinkingBlock(t *testing.T, message anthropicMessage, wantThinking string, wantSignature string) {
+	t.Helper()
+	if len(message.Content) == 0 {
+		t.Fatalf("expected non-empty content for %s message", message.Role)
+	}
+	first := message.Content[0]
+	if blockType := anthropicStringField(first, "type"); blockType != "thinking" {
+		t.Fatalf("expected first block type=thinking, got %s", blockType)
+	}
+	if got := anthropicStringField(first, "thinking"); got != wantThinking {
+		t.Fatalf("expected thinking=%q, got %q", wantThinking, got)
+	}
+	if got := anthropicStringField(first, "signature"); got != wantSignature {
+		t.Fatalf("expected signature=%q, got %q", wantSignature, got)
+	}
+}