diff --git a/docs/content/docs/guides/sequences.mdx b/docs/content/docs/guides/sequences.mdx
index 2ecbfce60..f12592942 100644
--- a/docs/content/docs/guides/sequences.mdx
+++ b/docs/content/docs/guides/sequences.mdx
@@ -219,6 +219,8 @@ The **On reply** button on a step card creates an action step connected by a rep
 
 A campaign-level toggle in the flow toolbar. When on and a contact replies, the rest of the cold sequence stops for them while the reply branch on the email they answered still runs instantly.
 
+Only inbound mail from that campaign contact to the sending mailbox counts. A threaded follow-up synchronized from Sent or Drafts stays outbound even though its `In-Reply-To` header points at an earlier campaign step.
+
 <Callout type="warn" title="Turn on stop on reply">
 With it off and more than one step, Warmbly warns you on the canvas: replies that don't match a reply branch would otherwise keep receiving cold follow-ups. Turning it on still runs your reply branches, so it is strictly safer.
 </Callout>
diff --git a/internal/app/advanced/incoming_reply_test.go b/internal/app/advanced/incoming_reply_test.go
new file mode 100644
index 000000000..324da97e7
--- /dev/null
+++ b/internal/app/advanced/incoming_reply_test.go
@@ -0,0 +1,294 @@
+package advanced
+
+import (
+	"context"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/warmbly/warmbly/internal/errx"
+	"github.com/warmbly/warmbly/internal/models"
+	"github.com/warmbly/warmbly/internal/repository"
+)
+
+type incomingReplyAdvancedRepo struct {
+	repository.AdvancedOutreachRepository
+}
+
+func (incomingReplyAdvancedRepo) GetOutreachSettings(context.Context, uuid.UUID) (*models.AdvancedOutreachSettings, error) {
+	settings := models.DefaultAdvancedOutreachSettings()
+	return &settings, nil
+}
+
+func (incomingReplyAdvancedRepo) MarkVariantEvent(context.Context, uuid.UUID, uuid.UUID, string) error {
+	return nil
+}
+
+func (incomingReplyAdvancedRepo) CreateReplyIntent(context.Context, *models.ReplyIntentRecord) error {
+	return nil
+}
+
+type incomingReplyEmailRepo struct {
+	repository.EmailRepository
+	account *models.Email
+}
+
+func (r incomingReplyEmailRepo) GetByID(context.Context, uuid.UUID) (*models.Email, *errx.Error) {
+	return r.account, nil
+}
+
+type incomingReplyTaskRepo struct {
+	repository.TaskRepository
+	task     *repository.Task
+	campaign *repository.CampaignTask
+}
+
+func (r incomingReplyTaskRepo) GetTaskByMessageID(context.Context, string) (*repository.Task, error) {
+	return r.task, nil
+}
+
+func (r incomingReplyTaskRepo) GetCampaignTask(context.Context, uuid.UUID) (*repository.CampaignTask, error) {
+	return r.campaign, nil
+}
+
+type incomingReplyContactRepo struct {
+	repository.ContactRepository
+	senderContact *models.Contact
+	taskContact   *models.Contact
+}
+
+func (r incomingReplyContactRepo) GetByEmailAndOrganization(context.Context, uuid.UUID, string) (*models.Contact, *errx.Error) {
+	return r.senderContact, nil
+}
+
+func (r incomingReplyContactRepo) GetByID(context.Context, uuid.UUID) (*models.Contact, *errx.Error) {
+	return r.taskContact, nil
+}
+
+type incomingReplyProgressRepo struct {
+	repository.CampaignProgressRepository
+	replied int
+	latest  *repository.CampaignSequencePair
+}
+
+func (r *incomingReplyProgressRepo) GetLatestCampaignSequenceForContact(context.Context, uuid.UUID) (*repository.CampaignSequencePair, error) {
+	return r.latest, nil
+}
+
+func (r *incomingReplyProgressRepo) GetLatestReplyClass(context.Context, uuid.UUID, uuid.UUID) (string, error) {
+	return "", nil
+}
+
+func (r *incomingReplyProgressRepo) RecordReplyClassification(context.Context, uuid.UUID, uuid.UUID, uuid.UUID, string, string, float64) error {
+	return nil
+}
+
+func (r *incomingReplyProgressRepo) RecordEmailReplied(context.Context, uuid.UUID, uuid.UUID, uuid.UUID) error {
+	r.replied++
+	return nil
+}
+
+type incomingReplyCampaignRepo struct{ repository.CampaignRepository }
+
+func (incomingReplyCampaignRepo) GetSequencesRoutingByCampaignID(context.Context, uuid.UUID) ([]models.Sequence, error) {
+	return nil, nil
+}
+
+func newIncomingReplyService(account *models.Email, senderContact *models.Contact, taskContact uuid.UUID) (*service, *incomingReplyProgressRepo) {
+	taskID, campaignID, sequenceID := uuid.New(), uuid.New(), uuid.New()
+	progress := &incomingReplyProgressRepo{}
+	taskContactRecord := &models.Contact{ID: taskContact, Email: "task-contact@example.test"}
+	if senderContact != nil && senderContact.ID == taskContact {
+		taskContactRecord = senderContact
+	}
+	return &service{
+		repo:         incomingReplyAdvancedRepo{},
+		campaignRepo: incomingReplyCampaignRepo{},
+		emailRepo:    incomingReplyEmailRepo{account: account},
+		taskRepo: incomingReplyTaskRepo{
+			task:     &repository.Task{ID: taskID, TaskType: "campaign", EmailAccountID: account.ID},
+			campaign: &repository.CampaignTask{TaskID: taskID, CampaignID: &campaignID, ContactID: &taskContact, SequenceID: &sequenceID},
+		},
+		contactRepo: incomingReplyContactRepo{
+			senderContact: senderContact,
+			taskContact:   taskContactRecord,
+		},
+		campaignProgressRepo: progress,
+	}, progress
+}
+
+func TestMessageAddressesMailbox(t *testing.T) {
+	account := &models.Email{
+		Email:       "mailbox@example.test",
+		SendAsEmail: "alias@example.test",
+		ReplyTo:     "replies@example.test",
+	}
+	for _, tc := range []struct {
+		name    string
+		message *models.EmailMessageStoreData
+		want    bool
+	}{
+		{name: "mailbox in to", message: &models.EmailMessageStoreData{ToAddr: []string{"Mailbox <mailbox@example.test>"}}, want: true},
+		{name: "send alias in cc", message: &models.EmailMessageStoreData{CC: []string{"alias@example.test"}}, want: true},
+		{name: "reply address in bcc", message: &models.EmailMessageStoreData{BCC: []string{"replies@example.test"}}, want: true},
+		{name: "different recipient", message: &models.EmailMessageStoreData{ToAddr: []string{"other@example.test"}}},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := messageAddressesMailbox(tc.message, account); got != tc.want {
+				t.Fatalf("messageAddressesMailbox() = %t, want %t", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestProcessIncomingReplyRejectsMailboxOwnSentCopy(t *testing.T) {
+	orgID, accountID, contactID := uuid.New(), uuid.New(), uuid.New()
+	account := &models.Email{ID: accountID, OrganizationID: &orgID, Email: "sender@example.test"}
+	service, progress := newIncomingReplyService(account, nil, contactID)
+
+	xerr := service.ProcessIncomingReply(context.Background(), accountID, &models.EmailMessageStoreData{
+		EmailID:   accountID,
+		Folder:    models.FolderInbox,
+		FromAddr:  []string{"Sender <sender@example.test>"},
+		ToAddr:    []string{"recipient@example.test"},
+		InReplyTo: []string{"<opener@example.test>"},
+		Subject:   "Re: Hello",
+	})
+	if xerr != nil {
+		t.Fatal(xerr)
+	}
+	if progress.replied != 0 {
+		t.Fatalf("RecordEmailReplied calls = %d, want 0 for the mailbox's own outbound copy", progress.replied)
+	}
+}
+
+func TestProcessIncomingReplyRejectsOutboundFolder(t *testing.T) {
+	for _, tc := range []struct {
+		name, folder, providerFolder string
+	}{
+		{name: "sent", folder: models.FolderSent},
+		{name: "draft", folder: models.FolderDrafts},
+		{name: "provider sent", folder: models.FolderInbox, providerFolder: models.FolderSent},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			orgID, accountID, contactID := uuid.New(), uuid.New(), uuid.New()
+			account := &models.Email{ID: accountID, OrganizationID: &orgID, Email: "sender@example.test"}
+			service, progress := newIncomingReplyService(account, &models.Contact{
+				ID: contactID, Email: "recipient@example.test",
+			}, contactID)
+
+			xerr := service.ProcessIncomingReply(context.Background(), accountID, &models.EmailMessageStoreData{
+				EmailID:        accountID,
+				Folder:         tc.folder,
+				ProviderFolder: tc.providerFolder,
+				FromAddr:       []string{"Recipient <recipient@example.test>"},
+				ToAddr:         []string{"sender@example.test"},
+				InReplyTo:      []string{"<opener@example.test>"},
+				Subject:        "Re: Hello",
+			})
+			if xerr != nil {
+				t.Fatal(xerr)
+			}
+			if progress.replied != 0 {
+				t.Fatalf("RecordEmailReplied calls = %d, want 0 for outbound folder", progress.replied)
+			}
+		})
+	}
+}
+
+func TestProcessIncomingReplyRequiresThreadSenderToMatchContact(t *testing.T) {
+	orgID, accountID := uuid.New(), uuid.New()
+	taskContactID, senderContactID := uuid.New(), uuid.New()
+	account := &models.Email{ID: accountID, OrganizationID: &orgID, Email: "sender@example.test"}
+	service, progress := newIncomingReplyService(account, &models.Contact{
+		ID: senderContactID, Email: "other@example.test",
+	}, taskContactID)
+	latestCampaignID, latestSequenceID := uuid.New(), uuid.New()
+	progress.latest = &repository.CampaignSequencePair{CampaignID: latestCampaignID, SequenceID: latestSequenceID}
+
+	xerr := service.ProcessIncomingReply(context.Background(), accountID, &models.EmailMessageStoreData{
+		EmailID:   accountID,
+		Folder:    models.FolderInbox,
+		FromAddr:  []string{"Other person <other@example.test>"},
+		ToAddr:    []string{"sender@example.test"},
+		InReplyTo: []string{"<opener@example.test>"},
+		Subject:   "Re: Hello",
+	})
+	if xerr != nil {
+		t.Fatal(xerr)
+	}
+	if progress.replied != 0 {
+		t.Fatalf("RecordEmailReplied calls = %d, want 0 when the threaded sender is a different contact", progress.replied)
+	}
+}
+
+func TestProcessIncomingReplyRequiresRecipientToMatchMailbox(t *testing.T) {
+	orgID, accountID, contactID := uuid.New(), uuid.New(), uuid.New()
+	account := &models.Email{ID: accountID, OrganizationID: &orgID, Email: "sender@example.test"}
+	service, progress := newIncomingReplyService(account, &models.Contact{
+		ID: contactID, Email: "recipient@example.test",
+	}, contactID)
+
+	xerr := service.ProcessIncomingReply(context.Background(), accountID, &models.EmailMessageStoreData{
+		EmailID:   accountID,
+		Folder:    models.FolderInbox,
+		FromAddr:  []string{"Recipient <recipient@example.test>"},
+		ToAddr:    []string{"someone-else@example.test"},
+		InReplyTo: []string{"<opener@example.test>"},
+		Subject:   "Re: Hello",
+	})
+	if xerr != nil {
+		t.Fatal(xerr)
+	}
+	if progress.replied != 0 {
+		t.Fatalf("RecordEmailReplied calls = %d, want 0 when the recipient is not the sending mailbox", progress.replied)
+	}
+}
+
+func TestProcessIncomingReplyRequiresThreadToMatchMailbox(t *testing.T) {
+	orgID, accountID, contactID := uuid.New(), uuid.New(), uuid.New()
+	account := &models.Email{ID: accountID, OrganizationID: &orgID, Email: "sender@example.test"}
+	service, progress := newIncomingReplyService(account, &models.Contact{
+		ID: contactID, Email: "recipient@example.test",
+	}, contactID)
+	service.taskRepo.(incomingReplyTaskRepo).task.EmailAccountID = uuid.New()
+	latestCampaignID, latestSequenceID := uuid.New(), uuid.New()
+	progress.latest = &repository.CampaignSequencePair{CampaignID: latestCampaignID, SequenceID: latestSequenceID}
+
+	xerr := service.ProcessIncomingReply(context.Background(), accountID, &models.EmailMessageStoreData{
+		EmailID:   accountID,
+		Folder:    models.FolderInbox,
+		FromAddr:  []string{"Recipient <recipient@example.test>"},
+		ToAddr:    []string{"sender@example.test"},
+		InReplyTo: []string{"<opener@example.test>"},
+		Subject:   "Re: Hello",
+	})
+	if xerr != nil {
+		t.Fatal(xerr)
+	}
+	if progress.replied != 0 {
+		t.Fatalf("RecordEmailReplied calls = %d, want 0 when the thread belongs to another mailbox", progress.replied)
+	}
+}
+
+func TestProcessIncomingReplyAcceptsMatchingThreadSender(t *testing.T) {
+	orgID, accountID, contactID := uuid.New(), uuid.New(), uuid.New()
+	account := &models.Email{ID: accountID, OrganizationID: &orgID, Email: "sender@example.test"}
+	service, progress := newIncomingReplyService(account, &models.Contact{
+		ID: contactID, Email: "recipient@example.test",
+	}, contactID)
+
+	xerr := service.ProcessIncomingReply(context.Background(), accountID, &models.EmailMessageStoreData{
+		EmailID:   accountID,
+		Folder:    models.FolderInbox,
+		FromAddr:  []string{"Recipient <recipient@example.test>"},
+		ToAddr:    []string{"sender@example.test"},
+		InReplyTo: []string{"<opener@example.test>"},
+		Subject:   "Re: Hello",
+	})
+	if xerr != nil {
+		t.Fatal(xerr)
+	}
+	if progress.replied != 1 {
+		t.Fatalf("RecordEmailReplied calls = %d, want 1 for the matching contact", progress.replied)
+	}
+}
diff --git a/internal/app/advanced/service.go b/internal/app/advanced/service.go
index f7bd868cf..f5d5e7c1e 100644
--- a/internal/app/advanced/service.go
+++ b/internal/app/advanced/service.go
@@ -880,6 +880,37 @@ func parseSenderEmail(addrs []string) string {
 	return strings.ToLower(strings.Trim(primary, "<>"))
 }
 
+func messageAddressesMailbox(msg *models.EmailMessageStoreData, account *models.Email) bool {
+	if msg == nil || account == nil {
+		return false
+	}
+	targets := make(map[string]struct{}, 3)
+	for _, raw := range []string{account.Email, account.SendFrom(), account.ReplyTo} {
+		if address := parseSenderEmail([]string{raw}); address != "" {
+			targets[address] = struct{}{}
+		}
+	}
+	for _, fields := range [][]string{msg.ToAddr, msg.CC, msg.BCC} {
+		for _, raw := range fields {
+			addresses, err := mail.ParseAddressList(raw)
+			if err != nil {
+				if address := parseSenderEmail([]string{raw}); address != "" {
+					if _, ok := targets[address]; ok {
+						return true
+					}
+				}
+				continue
+			}
+			for _, address := range addresses {
+				if _, ok := targets[strings.ToLower(strings.TrimSpace(address.Address))]; ok {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
 func cleanMessageID(mid string) string {
 	return strings.TrimSpace(strings.Trim(mid, "<>"))
 }
@@ -1035,6 +1066,9 @@ func classifyReply(text string, cfg models.ReplyIntentSettings) (models.ReplyInt
 }
 
 func (s *service) ProcessIncomingReply(ctx context.Context, emailAccountID uuid.UUID, msg *models.EmailMessageStoreData) *errx.Error {
+	if !msg.MayBeInbound() {
+		return nil
+	}
 	account, xerr := s.emailRepo.GetByID(ctx, emailAccountID)
 	if xerr != nil {
 		return xerr
@@ -1055,6 +1089,12 @@ func (s *service) ProcessIncomingReply(ctx context.Context, emailAccountID uuid.
 	if sender == "" {
 		return nil
 	}
+	if sender == parseSenderEmail([]string{account.Email}) || sender == parseSenderEmail([]string{account.SendFrom()}) {
+		return nil
+	}
+	if !messageAddressesMailbox(msg, account) {
+		return nil
+	}
 
 	text := strings.TrimSpace(msg.Snippet)
 	text = strings.TrimSpace(text + "\n" + msg.Subject)
@@ -1071,6 +1111,7 @@ func (s *service) ProcessIncomingReply(ctx context.Context, emailAccountID uuid.
 	var sequenceID *uuid.UUID
 	var contactID *uuid.UUID
 	var taskID *uuid.UUID
+	var referencesCampaignThread bool
 
 	// First, try exact message threading via In-Reply-To.
 	for _, mid := range msg.InReplyTo {
@@ -1082,13 +1123,25 @@ func (s *service) ProcessIncomingReply(ctx context.Context, emailAccountID uuid.
 		if err != nil || task == nil || task.TaskType != "campaign" {
 			continue
 		}
-		taskID = &task.ID
-		ct, err := s.taskRepo.GetCampaignTask(ctx, task.ID)
-		if err == nil && ct != nil {
-			campaignID = ct.CampaignID
-			contactID = ct.ContactID
-			sequenceID = ct.SequenceID
+		referencesCampaignThread = true
+		if task.EmailAccountID != emailAccountID {
+			continue
 		}
+		ct, err := s.taskRepo.GetCampaignTask(ctx, task.ID)
+		if err != nil || ct == nil || ct.ContactID == nil {
+			continue
+		}
+		contact, contactErr := s.contactRepo.GetByID(ctx, *ct.ContactID)
+		if contactErr != nil {
+			return contactErr
+		}
+		if contact == nil || !strings.EqualFold(strings.TrimSpace(contact.Email), sender) {
+			continue
+		}
+		taskID = &task.ID
+		campaignID = ct.CampaignID
+		contactID = ct.ContactID
+		sequenceID = ct.SequenceID
 		break
 	}
 
@@ -1102,7 +1155,7 @@ func (s *service) ProcessIncomingReply(ctx context.Context, emailAccountID uuid.
 		}
 	}
 
-	if campaignID == nil && contactID != nil {
+	if campaignID == nil && contactID != nil && !referencesCampaignThread {
 		latest, err := s.campaignProgressRepo.GetLatestCampaignSequenceForContact(ctx, *contactID)
 		if err == nil && latest != nil {
 			campaignID = &latest.CampaignID
diff --git a/internal/app/consumer/event_new_email.go b/internal/app/consumer/event_new_email.go
index 202beb6e4..024e79637 100644
--- a/internal/app/consumer/event_new_email.go
+++ b/internal/app/consumer/event_new_email.go
@@ -97,7 +97,7 @@ func (s *JobsService) ingestNewEmail(ctx context.Context, e *models.JobEventNewE
 	// (replyclassify) and persists reply_class/confidence/source on the contact's
 	// campaign progress, gating replied_at so automated replies (auto_reply /
 	// out_of_office) never count as a human reply for stop_on_reply / branching.
-	if s.AdvancedService != nil {
+	if s.AdvancedService != nil && e.Message.MayBeInbound() {
 		// Logged, not propagated: the ingest must survive it, but a silent
 		// failure here is indistinguishable from a reply that linked fine.
 		if xerr := s.AdvancedService.ProcessIncomingReply(ctx, e.Message.EmailID, e.Message); xerr != nil {
diff --git a/internal/app/consumer/event_new_email_test.go b/internal/app/consumer/event_new_email_test.go
new file mode 100644
index 000000000..e0c63fe9a
--- /dev/null
+++ b/internal/app/consumer/event_new_email_test.go
@@ -0,0 +1,76 @@
+package jobs
+
+import (
+	"context"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/warmbly/warmbly/internal/app/advanced"
+	"github.com/warmbly/warmbly/internal/errx"
+	"github.com/warmbly/warmbly/internal/models"
+	"github.com/warmbly/warmbly/internal/repository"
+)
+
+type replyRecordingAdvanced struct {
+	advanced.Service
+	calls int
+}
+
+func (s *replyRecordingAdvanced) ProcessIncomingReply(context.Context, uuid.UUID, *models.EmailMessageStoreData) *errx.Error {
+	s.calls++
+	return nil
+}
+
+type newEmailInboxRepo struct{ repository.UniboxRepository }
+
+func (newEmailInboxRepo) CreateEntry(context.Context, uuid.UUID, *models.EmailMessageStoreData) error {
+	return nil
+}
+
+type newEmailAccountRepo struct{ repository.EmailRepository }
+
+func (newEmailAccountRepo) GetByID(context.Context, uuid.UUID) (*models.Email, *errx.Error) {
+	return nil, nil
+}
+
+func TestHandleNewEmailDoesNotProcessSentMailAsReply(t *testing.T) {
+	for _, tc := range []struct {
+		name, folder, providerFolder string
+		wantCalls                    int
+	}{
+		{name: "sent follow-up", folder: models.FolderSent},
+		{name: "provider still reports sent", folder: models.FolderInbox, providerFolder: models.FolderSent},
+		{name: "draft", folder: models.FolderDrafts},
+		{name: "inbox", folder: models.FolderInbox, wantCalls: 1},
+		{name: "archived inbound", folder: models.FolderArchive, wantCalls: 1},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			advancedService := &replyRecordingAdvanced{}
+			service := &JobsService{
+				UniboxRepository: newEmailInboxRepo{},
+				EmailRepository:  newEmailAccountRepo{},
+				AdvancedService:  advancedService,
+			}
+
+			err := service.HandleNewEmail(context.Background(), &models.JobEventNewEmail{
+				UserID: uuid.New(),
+				Message: &models.EmailMessageStoreData{
+					ID:             uuid.New(),
+					EmailID:        uuid.New(),
+					Folder:         tc.folder,
+					ProviderFolder: tc.providerFolder,
+					FromAddr:       []string{"sender@example.test"},
+					ToAddr:         []string{"recipient@example.test"},
+					MessageID:      "<follow-up@example.test>",
+					InReplyTo:      []string{"<opener@example.test>"},
+				},
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if advancedService.calls != tc.wantCalls {
+				t.Fatalf("ProcessIncomingReply calls = %d, want %d", advancedService.calls, tc.wantCalls)
+			}
+		})
+	}
+}
diff --git a/internal/models/unibox.go b/internal/models/unibox.go
index 5163b2f11..26296f07f 100644
--- a/internal/models/unibox.go
+++ b/internal/models/unibox.go
@@ -270,6 +270,19 @@ func NormalizeFolder(folder string, flags []string) string {
 	return FolderInbox
 }
 
+func outboundOnlyFolder(folder string) bool {
+	return folder == FolderSent || folder == FolderDrafts
+}
+
+// MayBeInbound reports whether neither folder placement proves the message outbound.
+func (e *EmailMessageStoreData) MayBeInbound() bool {
+	if e == nil {
+		return false
+	}
+	return !outboundOnlyFolder(NormalizeFolder(e.Folder, e.Flags)) &&
+		!outboundOnlyFolder(e.ProviderFolder)
+}
+
 type MailSearchResult struct {
 	Data       []EmailMessageStoreDataPreview `json:"data"`
 	Pagination CPagination                    `json:"pagination"`