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internal/multiagent/continuation_user_dedup_middleware.go

@@ -0,0 +1,104 @@
+package multiagent
+
+import (
+	"context"
+	"strings"
+
+	"github.com/cloudwego/eino/adk"
+	"github.com/cloudwego/eino/schema"
+	"go.uber.org/zap"
+)
+
+// continuationSessionMarker matches Cursor / IDE session-resume user injections.
+const continuationSessionMarker = "This session is being continued from a previous conversation"
+
+// continuationUserDedupMiddleware keeps only the latest session-resume user message when
+// multiple continuation injections were stacked (e.g. after repeated out-of-context resumes).
+type continuationUserDedupMiddleware struct {
+	adk.BaseChatModelAgentMiddleware
+	logger *zap.Logger
+	phase  string
+}
+
+func newContinuationUserDedupMiddleware(logger *zap.Logger, phase string) adk.ChatModelAgentMiddleware {
+	return &continuationUserDedupMiddleware{logger: logger, phase: phase}
+}
+
+func (m *continuationUserDedupMiddleware) BeforeModelRewriteState(
+	ctx context.Context,
+	state *adk.ChatModelAgentState,
+	mc *adk.ModelContext,
+) (context.Context, *adk.ChatModelAgentState, error) {
+	_ = mc
+	if m == nil || state == nil || len(state.Messages) == 0 {
+		return ctx, state, nil
+	}
+	deduped, dropped := dedupContinuationUserMessages(state.Messages)
+	if dropped == 0 {
+		return ctx, state, nil
+	}
+	if m.logger != nil {
+		m.logger.Info("eino continuation user messages deduplicated",
+			zap.String("phase", m.phase),
+			zap.Int("dropped", dropped),
+			zap.Int("messages_before", len(state.Messages)),
+			zap.Int("messages_after", len(deduped)),
+		)
+	}
+	out := *state
+	out.Messages = deduped
+	return ctx, &out, nil
+}
+
+func adkUserMessageText(msg adk.Message) string {
+	if msg == nil {
+		return ""
+	}
+	var b strings.Builder
+	if s := strings.TrimSpace(msg.Content); s != "" {
+		b.WriteString(s)
+	}
+	for _, part := range msg.UserInputMultiContent {
+		if part.Type == schema.ChatMessagePartTypeText {
+			if s := strings.TrimSpace(part.Text); s != "" {
+				if b.Len() > 0 {
+					b.WriteByte('\n')
+				}
+				b.WriteString(s)
+			}
+		}
+	}
+	return b.String()
+}
+
+func isContinuationUserMessage(msg adk.Message) bool {
+	if msg == nil || msg.Role != schema.User {
+		return false
+	}
+	return strings.Contains(adkUserMessageText(msg), continuationSessionMarker)
+}
+
+func dedupContinuationUserMessages(msgs []adk.Message) ([]adk.Message, int) {
+	lastIdx := -1
+	contCount := 0
+	for i, msg := range msgs {
+		if !isContinuationUserMessage(msg) {
+			continue
+		}
+		contCount++
+		lastIdx = i
+	}
+	if contCount <= 1 {
+		return msgs, 0
+	}
+	out := make([]adk.Message, 0, len(msgs)-(contCount-1))
+	dropped := 0
+	for i, msg := range msgs {
+		if isContinuationUserMessage(msg) && i != lastIdx {
+			dropped++
+			continue
+		}
+		out = append(out, msg)
+	}
+	return out, dropped
+}