diff --git a/internal/backend/forwarder/artifacts.go b/internal/backend/forwarder/artifacts.go
index c194cfd..715a50c 100644
--- a/internal/backend/forwarder/artifacts.go
+++ b/internal/backend/forwarder/artifacts.go
@@ -23,10 +23,10 @@ type artifactRecorder struct {
 }
 
 type artifactSession struct {
-	conversationID string
-	turnSeq        int64
-	requestPayload map[string]any
-	summaryPayload map[string]any
+	conversationID   string
+	turnSeq          int64
+	requestPrefix    requestArtifactPrefix
+	hasRequestPrefix bool
 }
 
 type requestArtifactPrefix struct {
@@ -57,14 +57,22 @@ func (recorder *artifactRecorder) RecordLLMRequest(requestID string, _ string, m
 	if err != nil {
 		return "", err
 	}
-	session.requestPayload = cloneStringAnyMap(payload)
+	prefix, hasPrefix, prefixErr := decodeRequestPrefixPayload(payload)
+	session.requestPrefix = requestArtifactPrefix{}
+	session.hasRequestPrefix = false
+	if prefixErr == nil && hasPrefix && prefix != nil {
+		session.requestPrefix = *prefix
+		session.hasRequestPrefix = true
+	}
 	recorder.mu.Lock()
 	recorder.sessions[artifactSessionKey(requestID, modelCallID)] = session
 	recorder.mu.Unlock()
-	if prefix, ok, err := decodeRequestPrefixPayload(session.requestPayload); err == nil && ok && prefix != nil {
+	if prefixErr == nil && hasPrefix && prefix != nil {
 		recorder.persistLatestRequestPrefix(session.conversationID, requestID, modelCallID, prefix)
 	}
-	recorder.debug.LogProviderArtifact(context.Background(), requestID, session.conversationID, modelCallID, "llm_request", session.requestPayload)
+	// The payload is serialized synchronously for debug output and is deliberately
+	// not retained in sessions: it can contain the entire replayed conversation.
+	recorder.debug.LogProviderArtifact(context.Background(), requestID, session.conversationID, modelCallID, "llm_request", payload)
 	return "", nil
 }
 
@@ -86,17 +94,16 @@ func (recorder *artifactRecorder) RecordLLMSummary(requestID string, _ string, m
 	if err != nil {
 		return "", err
 	}
-	session.summaryPayload = cloneStringAnyMap(payload)
-	recorder.mu.Lock()
-	recorder.sessions[artifactSessionKey(requestID, modelCallID)] = session
-	recorder.mu.Unlock()
-	if prefix, ok, err := decodeRequestPrefixPayload(session.requestPayload); err == nil && ok && prefix != nil {
-		if tokens := readInt64Value(session.summaryPayload["prompt_tokens_total"]); tokens > 0 {
-			prefix.PromptTokensTotal = tokens
+	if session.hasRequestPrefix {
+		if tokens := readInt64Value(payload["prompt_tokens_total"]); tokens > 0 {
+			session.requestPrefix.PromptTokensTotal = tokens
 		}
-		recorder.persistLatestRequestPrefix(session.conversationID, requestID, modelCallID, prefix)
+		recorder.mu.Lock()
+		recorder.sessions[artifactSessionKey(requestID, modelCallID)] = session
+		recorder.mu.Unlock()
+		recorder.persistLatestRequestPrefix(session.conversationID, requestID, modelCallID, &session.requestPrefix)
 	}
-	recorder.debug.LogProviderArtifact(context.Background(), requestID, session.conversationID, modelCallID, "llm_summary", session.summaryPayload)
+	recorder.debug.LogProviderArtifact(context.Background(), requestID, session.conversationID, modelCallID, "llm_summary", payload)
 	return "", nil
 }
 
diff --git a/internal/backend/forwarder/json_helpers.go b/internal/backend/forwarder/json_helpers.go
index 95cec74..ad06599 100644
--- a/internal/backend/forwarder/json_helpers.go
+++ b/internal/backend/forwarder/json_helpers.go
@@ -10,21 +10,6 @@ import (
 	modeladapter "cursor/internal/backend/agent/model"
 )
 
-func cloneStringAnyMap(value map[string]any) map[string]any {
-	if len(value) == 0 {
-		return nil
-	}
-	payload, err := json.Marshal(value)
-	if err != nil {
-		return nil
-	}
-	var decoded map[string]any
-	if err := json.Unmarshal(payload, &decoded); err != nil {
-		return nil
-	}
-	return decoded
-}
-
 func parseRFC3339Time(value string) time.Time {
 	trimmed := strings.TrimSpace(value)
 	if trimmed == "" {
diff --git a/internal/backend/forwarder/provider.go b/internal/backend/forwarder/provider.go
index 23ec356..b37e317 100644
--- a/internal/backend/forwarder/provider.go
+++ b/internal/backend/forwarder/provider.go
@@ -25,6 +25,7 @@ func (gateway *DefaultProviderGateway) StartStream(ctx context.Context, req Prov
 	if ctx == nil {
 		ctx = context.Background()
 	}
+	defer releaseArtifactSession(req.Observer, req.RequestID, req.ModelCallID)
 	requestKnobs := make(map[string]any, len(req.RequestKnobs)+2)
 	for key, value := range req.RequestKnobs {
 		requestKnobs[key] = value
@@ -60,3 +61,15 @@ func (gateway *DefaultProviderGateway) StartStream(ctx context.Context, req Prov
 	}
 	return nil
 }
+
+type artifactSessionCleaner interface {
+	ClearActiveArtifacts(requestID string, modelCallID string)
+}
+
+func releaseArtifactSession(observer modeladapter.LLMArtifactObserver, requestID string, modelCallID string) {
+	cleaner, ok := observer.(artifactSessionCleaner)
+	if !ok {
+		return
+	}
+	cleaner.ClearActiveArtifacts(requestID, modelCallID)
+}