diff --git a/backend/pkg/database/msgchains.sql.go b/backend/pkg/database/msgchains.sql.go
index 678188b2f..a036d1dde 100644
--- a/backend/pkg/database/msgchains.sql.go
+++ b/backend/pkg/database/msgchains.sql.go
@@ -203,6 +203,55 @@ func (q *Queries) GetFlowMsgChains(ctx context.Context, flowID int64) ([]Msgchai
 	return items, nil
 }
 
+const getFlowTaskSubtaskTypeLastMsgChain = `-- name: GetFlowTaskSubtaskTypeLastMsgChain :one
+SELECT
+  mc.id, mc.type, mc.model, mc.model_provider, mc.usage_in, mc.usage_out, mc.chain, mc.flow_id, mc.task_id, mc.subtask_id, mc.created_at, mc.updated_at, mc.usage_cache_in, mc.usage_cache_out, mc.usage_cost_in, mc.usage_cost_out, mc.duration_seconds
+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
+`
+
+type GetFlowTaskSubtaskTypeLastMsgChainParams struct {
+	FlowID    int64         `json:"flow_id"`
+	TaskID    sql.NullInt64 `json:"task_id"`
+	SubtaskID sql.NullInt64 `json:"subtask_id"`
+	Type      MsgchainType  `json:"type"`
+}
+
+func (q *Queries) GetFlowTaskSubtaskTypeLastMsgChain(ctx context.Context, arg GetFlowTaskSubtaskTypeLastMsgChainParams) (Msgchain, error) {
+	row := q.db.QueryRowContext(ctx, getFlowTaskSubtaskTypeLastMsgChain,
+		arg.FlowID,
+		arg.TaskID,
+		arg.SubtaskID,
+		arg.Type,
+	)
+	var i Msgchain
+	err := row.Scan(
+		&i.ID,
+		&i.Type,
+		&i.Model,
+		&i.ModelProvider,
+		&i.UsageIn,
+		&i.UsageOut,
+		&i.Chain,
+		&i.FlowID,
+		&i.TaskID,
+		&i.SubtaskID,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.UsageCacheIn,
+		&i.UsageCacheOut,
+		&i.UsageCostIn,
+		&i.UsageCostOut,
+		&i.DurationSeconds,
+	)
+	return i, err
+}
+
 const getFlowTaskTypeLastMsgChain = `-- name: GetFlowTaskTypeLastMsgChain :one
 SELECT
   mc.id, mc.type, mc.model, mc.model_provider, mc.usage_in, mc.usage_out, mc.chain, mc.flow_id, mc.task_id, mc.subtask_id, mc.created_at, mc.updated_at, mc.usage_cache_in, mc.usage_cache_out, mc.usage_cost_in, mc.usage_cost_out, mc.duration_seconds
diff --git a/backend/pkg/database/querier.go b/backend/pkg/database/querier.go
index 7cb656e1e..d1e7bada2 100644
--- a/backend/pkg/database/querier.go
+++ b/backend/pkg/database/querier.go
@@ -101,6 +101,7 @@ type Querier interface {
 	GetFlowSubtask(ctx context.Context, arg GetFlowSubtaskParams) (Subtask, error)
 	GetFlowSubtasks(ctx context.Context, flowID int64) ([]Subtask, error)
 	GetFlowTask(ctx context.Context, arg GetFlowTaskParams) (Task, error)
+	GetFlowTaskSubtaskTypeLastMsgChain(ctx context.Context, arg GetFlowTaskSubtaskTypeLastMsgChainParams) (Msgchain, error)
 	GetFlowTaskSubtasks(ctx context.Context, arg GetFlowTaskSubtasksParams) ([]Subtask, error)
 	GetFlowTaskTypeLastMsgChain(ctx context.Context, arg GetFlowTaskTypeLastMsgChainParams) (Msgchain, error)
 	GetFlowTasks(ctx context.Context, flowID int64) ([]Task, error)
diff --git a/backend/pkg/providers/helpers.go b/backend/pkg/providers/helpers.go
index 7b3bb02df..f22e4c5aa 100644
--- a/backend/pkg/providers/helpers.go
+++ b/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) {
diff --git a/backend/pkg/providers/helpers_test.go b/backend/pkg/providers/helpers_test.go
index 2b4834871..f710be978 100644
--- a/backend/pkg/providers/helpers_test.go
+++ b/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,
diff --git a/backend/sqlc/models/msgchains.sql b/backend/sqlc/models/msgchains.sql
index 7639875e0..8d54a1301 100644
--- a/backend/sqlc/models/msgchains.sql
+++ b/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.*