fix(providers): scope restored chains to subtask

backend/pkg/providers/helpers.go

@@ -444,6 +444,19 @@ func (fp *flowProvider) getTaskMsgLogsSummary(
 	return summary, nil
 }
 
+func scopedMsgChainLookupParams(
+	flowID int64,
+	taskID, subtaskID *int64,
+	msgChainType database.MsgchainType,
+) database.GetFlowTaskSubtaskTypeLastMsgChainParams {
+	return database.GetFlowTaskSubtaskTypeLastMsgChainParams{
+		FlowID:    flowID,
+		TaskID:    database.Int64ToNullInt64(taskID),
+		SubtaskID: database.Int64ToNullInt64(subtaskID),
+		Type:      msgChainType,
+	}
+}
+
 func (fp *flowProvider) restoreChain(
 	ctx context.Context,
 	taskID, subtaskID *int64,
@@ -454,11 +467,9 @@ func (fp *flowProvider) restoreChain(
 	ctx, observation := obs.Observer.NewObservation(ctx)
 
 	// Get raw chain from DB for observation input
-	msgChain, err := fp.db.GetFlowTaskTypeLastMsgChain(ctx, database.GetFlowTaskTypeLastMsgChainParams{
-		FlowID: fp.flowID,
-		TaskID: database.Int64ToNullInt64(taskID),
-		Type:   msgChainType,
-	})
+	msgChain, err := fp.db.GetFlowTaskSubtaskTypeLastMsgChain(ctx, scopedMsgChainLookupParams(
+		fp.flowID, taskID, subtaskID, msgChainType,
+	))
 
 	var rawChain []llms.MessageContent
 	if err == nil && !isEmptyChain(msgChain.Chain) {

backend/pkg/providers/helpers_test.go

@@ -12,6 +12,7 @@ import (
 
 	"pentagi/pkg/cast"
 	"pentagi/pkg/config"
+	"pentagi/pkg/database"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/vxcontrol/langchaingo/llms"
@@ -1096,6 +1097,33 @@ func TestExecutionMonitorDetector_ShouldInvokeAdviser(t *testing.T) {
 	}
 }
 
+func TestScopedMsgChainLookupParams(t *testing.T) {
+	taskID := int64(12)
+	subtaskID := int64(34)
+
+	tests := []struct {
+		name      string
+		taskID    *int64
+		subtaskID *int64
+		wantTask  *int64
+		wantSub   *int64
+	}{
+		{name: "assistant scope keeps null identifiers"},
+		{name: "task scope keeps a null subtask", taskID: &taskID, wantTask: &taskID},
+		{name: "subtask scope includes both identifiers", taskID: &taskID, subtaskID: &subtaskID, wantTask: &taskID, wantSub: &subtaskID},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			params := scopedMsgChainLookupParams(7, tt.taskID, tt.subtaskID, database.MsgchainTypeCoder)
+			assert.Equal(t, int64(7), params.FlowID)
+			assert.Equal(t, database.Int64ToNullInt64(tt.wantTask), params.TaskID)
+			assert.Equal(t, database.Int64ToNullInt64(tt.wantSub), params.SubtaskID)
+			assert.Equal(t, database.MsgchainTypeCoder, params.Type)
+		})
+	}
+}
+
 func TestExecutionMonitorDetector_Reset(t *testing.T) {
 	emd := &executionMonitor{
 		enabled:        true,

backend/sqlc/models/msgchains.sql

@@ -77,6 +77,17 @@ WHERE mc.flow_id = $1 AND (mc.task_id = $2 OR $2 IS NULL) AND mc.type = $3
 ORDER BY mc.created_at DESC
 LIMIT 1;
 
+-- name: GetFlowTaskSubtaskTypeLastMsgChain :one
+SELECT
+  mc.*
+FROM msgchains mc
+WHERE mc.flow_id = $1
+  AND mc.task_id IS NOT DISTINCT FROM $2
+  AND mc.subtask_id IS NOT DISTINCT FROM $3
+  AND mc.type = $4
+ORDER BY mc.created_at DESC
+LIMIT 1;
+
 -- name: GetMsgChain :one
 SELECT
   mc.*