diff --git a/components/ambient-control-plane/internal/informer/informer.go b/components/ambient-control-plane/internal/informer/informer.go
index 01b6937aa..6d41f5d61 100644
--- a/components/ambient-control-plane/internal/informer/informer.go
+++ b/components/ambient-control-plane/internal/informer/informer.go
@@ -494,6 +494,7 @@ func protoSessionToSDK(s *pb.Session) types.Session {
 		LlmMaxTokens:         int(s.GetLlmMaxTokens()),
 		Timeout:              int(s.GetTimeout()),
 		ProjectID:            s.GetProjectId(),
+		AgentID:              s.GetAgentId(),
 		WorkflowID:           s.GetWorkflowId(),
 		BotAccountName:       s.GetBotAccountName(),
 		Labels:               s.GetLabels(),
diff --git a/components/ambient-control-plane/internal/informer/informer_test.go b/components/ambient-control-plane/internal/informer/informer_test.go
new file mode 100644
index 000000000..5b7447f67
--- /dev/null
+++ b/components/ambient-control-plane/internal/informer/informer_test.go
@@ -0,0 +1,143 @@
+package informer
+
+import (
+	"testing"
+	"time"
+
+	pb "github.com/ambient-code/platform/components/ambient-api-server/pkg/api/grpc/ambient/v1"
+	"google.golang.org/protobuf/types/known/timestamppb"
+)
+
+func strPtr(s string) *string    { return &s }
+func int32Ptr(i int32) *int32    { return &i }
+func float64Ptr(f float64) *float64 { return &f }
+
+func TestProtoSessionToSDK_NilReturnsZero(t *testing.T) {
+	s := protoSessionToSDK(nil)
+	if s.ID != "" || s.Name != "" {
+		t.Fatal("nil proto should produce zero-value Session")
+	}
+}
+
+func TestProtoSessionToSDK_StandaloneSession(t *testing.T) {
+	proto := &pb.Session{
+		Metadata: &pb.ObjectReference{Id: "session-standalone"},
+		Name:     "no-agent-session",
+		Prompt:   strPtr("just do the thing"),
+		ProjectId: strPtr("my-project"),
+	}
+
+	s := protoSessionToSDK(proto)
+
+	if s.AgentID != "" {
+		t.Errorf("AgentID: got %q, want empty string for standalone session", s.AgentID)
+	}
+	if s.Name != "no-agent-session" {
+		t.Errorf("Name: got %q, want %q", s.Name, "no-agent-session")
+	}
+	if s.Prompt != "just do the thing" {
+		t.Errorf("Prompt: got %q, want %q", s.Prompt, "just do the thing")
+	}
+}
+
+func TestProtoSessionToSDK_AllFieldsMapped(t *testing.T) {
+	now := time.Now().Truncate(time.Second)
+	later := now.Add(10 * time.Minute)
+	created := now.Add(-1 * time.Hour)
+	updated := now.Add(-30 * time.Minute)
+
+	proto := &pb.Session{
+		Metadata: &pb.ObjectReference{
+			Id:        "session-123",
+			CreatedAt: timestamppb.New(created),
+			UpdatedAt: timestamppb.New(updated),
+		},
+		Name:                 "test-session",
+		Prompt:               strPtr("do something"),
+		RepoUrl:              strPtr("https://github.com/example/repo"),
+		Repos:                strPtr(`[{"url":"https://github.com/example/repo"}]`),
+		LlmModel:             strPtr("claude-sonnet-4-6"),
+		LlmTemperature:       float64Ptr(0.7),
+		LlmMaxTokens:         int32Ptr(4000),
+		Timeout:              int32Ptr(3600),
+		ProjectId:            strPtr("my-project"),
+		AgentId:              strPtr("agent-456"),
+		WorkflowId:           strPtr("workflow-789"),
+		BotAccountName:       strPtr("bot-user"),
+		Labels:               strPtr(`{"env":"test"}`),
+		Annotations:          strPtr(`{"note":"hello"}`),
+		ResourceOverrides:    strPtr(`{"cpu":"2"}`),
+		EnvironmentVariables: strPtr(`{"FOO":"bar"}`),
+		CreatedByUserId:      strPtr("test-creator"),
+		AssignedUserId:       strPtr("test-assignee"),
+		ParentSessionId:      strPtr("parent-001"),
+		Phase:                strPtr("Running"),
+		KubeCrName:           strPtr("cr-name"),
+		KubeCrUid:            strPtr("cr-uid-abc"),
+		KubeNamespace:        strPtr("my-project"),
+		SdkSessionId:         strPtr("sdk-sess-id"),
+		SdkRestartCount:      int32Ptr(2),
+		Conditions:           strPtr("Ready"),
+		ReconciledRepos:      strPtr("reconciled"),
+		ReconciledWorkflow:   strPtr("wf-reconciled"),
+		StartTime:            timestamppb.New(now),
+		CompletionTime:       timestamppb.New(later),
+	}
+
+	s := protoSessionToSDK(proto)
+
+	checks := []struct {
+		field string
+		got   any
+		want  any
+	}{
+		{"ID", s.ID, "session-123"},
+		{"Name", s.Name, "test-session"},
+		{"Prompt", s.Prompt, "do something"},
+		{"RepoURL", s.RepoURL, "https://github.com/example/repo"},
+		{"Repos", s.Repos, `[{"url":"https://github.com/example/repo"}]`},
+		{"LlmModel", s.LlmModel, "claude-sonnet-4-6"},
+		{"LlmTemperature", s.LlmTemperature, 0.7},
+		{"LlmMaxTokens", s.LlmMaxTokens, 4000},
+		{"Timeout", s.Timeout, 3600},
+		{"ProjectID", s.ProjectID, "my-project"},
+		{"AgentID", s.AgentID, "agent-456"},
+		{"WorkflowID", s.WorkflowID, "workflow-789"},
+		{"BotAccountName", s.BotAccountName, "bot-user"},
+		{"Labels", s.Labels, `{"env":"test"}`},
+		{"Annotations", s.Annotations, `{"note":"hello"}`},
+		{"ResourceOverrides", s.ResourceOverrides, `{"cpu":"2"}`},
+		{"EnvironmentVariables", s.EnvironmentVariables, `{"FOO":"bar"}`},
+		{"CreatedByUserID", s.CreatedByUserID, "test-creator"},
+		{"AssignedUserID", s.AssignedUserID, "test-assignee"},
+		{"ParentSessionID", s.ParentSessionID, "parent-001"},
+		{"Phase", s.Phase, "Running"},
+		{"KubeCrName", s.KubeCrName, "cr-name"},
+		{"KubeCrUid", s.KubeCrUid, "cr-uid-abc"},
+		{"KubeNamespace", s.KubeNamespace, "my-project"},
+		{"SdkSessionID", s.SdkSessionID, "sdk-sess-id"},
+		{"SdkRestartCount", s.SdkRestartCount, 2},
+		{"Conditions", s.Conditions, "Ready"},
+		{"ReconciledRepos", s.ReconciledRepos, "reconciled"},
+		{"ReconciledWorkflow", s.ReconciledWorkflow, "wf-reconciled"},
+	}
+
+	for _, c := range checks {
+		if c.got != c.want {
+			t.Errorf("%s: got %v, want %v", c.field, c.got, c.want)
+		}
+	}
+
+	if s.CreatedAt == nil || !s.CreatedAt.Equal(created) {
+		t.Errorf("CreatedAt: got %v, want %v", s.CreatedAt, created)
+	}
+	if s.UpdatedAt == nil || !s.UpdatedAt.Equal(updated) {
+		t.Errorf("UpdatedAt: got %v, want %v", s.UpdatedAt, updated)
+	}
+	if s.StartTime == nil || !s.StartTime.Equal(now) {
+		t.Errorf("StartTime: got %v, want %v", s.StartTime, now)
+	}
+	if s.CompletionTime == nil || !s.CompletionTime.Equal(later) {
+		t.Errorf("CompletionTime: got %v, want %v", s.CompletionTime, later)
+	}
+}