fix(bedrock): strip context_management when beta is removed

backend/internal/service/bedrock_request.go

@@ -185,6 +185,7 @@ func BuildBedrockURL(region, modelID string, stream bool) string {
 //  5. 清理 cache_control 中 Bedrock 不支持的字段（scope, ttl）
 //  6. 修复 thinking 字段兼容性（Opus 4.7 仅支持 adaptive，enabled 需要 budget_tokens）
 //  7. 清理 tool_use.id / tool_use_id 中 Bedrock 不接受的字符
+//  8. 根据最终 Bedrock beta tokens 剥离不再支持的 beta 字段
 func PrepareBedrockRequestBody(body []byte, modelID string, betaHeader string) ([]byte, error) {
 	betaTokens := ResolveBedrockBetaTokens(betaHeader, body, modelID)
 	return PrepareBedrockRequestBodyWithTokens(body, modelID, betaTokens, false)
@@ -195,6 +196,9 @@ func PrepareBedrockRequestBody(body []byte, modelID string, betaHeader string) (
 func PrepareBedrockRequestBodyWithTokens(body []byte, modelID string, betaTokens []string, ccCompat bool) ([]byte, error) {
 	var err error
 
+	betaTokens = filterBedrockBetaTokens(betaTokens)
+	body = sanitizeBedrockFieldsForBetaTokens(body, betaTokens)
+
 	// 注入 anthropic_version（Bedrock 要求）
 	body, err = sjson.SetBytes(body, "anthropic_version", "bedrock-2023-05-31")
 	if err != nil {
@@ -471,6 +475,8 @@ var bedrockSupportedBetaTokens = map[string]bool{
 	"tool-examples-2025-10-29":    true,
 }
 
+const bedrockContextManagementBetaToken = "context-management-2025-06-27"
+
 // bedrockBetaTokenTransforms 定义 Bedrock Invoke 特有的 beta 头转换规则
 // Anthropic 直接 API 使用通用头，Bedrock Invoke 需要特定的替代头
 var bedrockBetaTokenTransforms = map[string]string{
@@ -617,6 +623,22 @@ func filterBedrockBetaTokens(tokens []string) []string {
 	return result
 }
 
+func sanitizeBedrockFieldsForBetaTokens(body []byte, betaTokens []string) []byte {
+	if !containsBedrockBetaToken(betaTokens, bedrockContextManagementBetaToken) && gjson.GetBytes(body, "context_management").Exists() {
+		body, _ = sjson.DeleteBytes(body, "context_management")
+	}
+	return body
+}
+
+func containsBedrockBetaToken(tokens []string, target string) bool {
+	for _, token := range tokens {
+		if token == target {
+			return true
+		}
+	}
+	return false
+}
+
 // bedrockToolUseIDRe 匹配 Bedrock 允许的 tool_use ID 字符（字母、数字、下划线、连字符）
 var bedrockToolUseIDRe = regexp.MustCompile(`[^a-zA-Z0-9_-]`)
 

backend/internal/service/bedrock_request_test.go

@@ -378,6 +378,67 @@ func TestPrepareBedrockRequestBody_BetaFiltering(t *testing.T) {
 	})
 }
 
+func TestPrepareBedrockRequestBodyWithTokens_ContextManagementRequiresSupportedBeta(t *testing.T) {
+	modelID := "us.anthropic.claude-opus-4-6-v1"
+
+	t.Run("strips context_management when final tokens omit context-management beta", func(t *testing.T) {
+		input := `{
+			"messages":[{"role":"user","content":"hi"}],
+			"max_tokens":100,
+			"context_management":{"edits":[{"type":"clear_thinking_20251015","keep":"all"}]}
+		}`
+		betaTokens := []string{"context-1m-2025-08-07"}
+		originalTokens := append([]string(nil), betaTokens...)
+
+		result, err := PrepareBedrockRequestBodyWithTokens([]byte(input), modelID, betaTokens, false)
+		require.NoError(t, err)
+
+		assert.False(t, gjson.GetBytes(result, "context_management").Exists())
+		assert.Equal(t, originalTokens, betaTokens)
+		assert.Equal(t, originalTokens, bedrockAnthropicBetaNames(result))
+	})
+
+	t.Run("leaves body without context_management otherwise intact", func(t *testing.T) {
+		input := `{"messages":[{"role":"user","content":"hi"}],"max_tokens":100}`
+
+		result, err := PrepareBedrockRequestBodyWithTokens([]byte(input), modelID, nil, false)
+		require.NoError(t, err)
+
+		assert.False(t, gjson.GetBytes(result, "context_management").Exists())
+		assert.False(t, gjson.GetBytes(result, "anthropic_beta").Exists())
+		assert.Equal(t, "hi", gjson.GetBytes(result, "messages.0.content").String())
+		assert.Equal(t, int64(100), gjson.GetBytes(result, "max_tokens").Int())
+	})
+
+	t.Run("filters explicit unsupported context-management beta and strips field", func(t *testing.T) {
+		input := `{
+			"messages":[{"role":"user","content":"hi"}],
+			"max_tokens":100,
+			"context_management":{"edits":[{"type":"clear_thinking_20251015","keep":"all"}]}
+		}`
+
+		result, err := PrepareBedrockRequestBodyWithTokens(
+			[]byte(input),
+			modelID,
+			[]string{bedrockContextManagementBetaToken, "context-1m-2025-08-07"},
+			false,
+		)
+		require.NoError(t, err)
+
+		assert.False(t, gjson.GetBytes(result, "context_management").Exists())
+		assert.Equal(t, []string{"context-1m-2025-08-07"}, bedrockAnthropicBetaNames(result))
+	})
+}
+
+func bedrockAnthropicBetaNames(body []byte) []string {
+	arr := gjson.GetBytes(body, "anthropic_beta").Array()
+	names := make([]string, len(arr))
+	for i, token := range arr {
+		names[i] = token.String()
+	}
+	return names
+}
+
 func TestBedrockCrossRegionPrefix(t *testing.T) {
 	tests := []struct {
 		region string