diff --git a/internal/cmd/mail.go b/internal/cmd/mail.go
index 6249605d..2f227567 100644
--- a/internal/cmd/mail.go
+++ b/internal/cmd/mail.go
@@ -22,6 +22,7 @@ var (
 	mailPriority      int
 	mailUrgent        bool
 	mailPinned        bool
+	mailEphemeral     bool
 	mailType          string
 	mailReplyTo       string
 	mailNotify        bool
@@ -235,6 +236,7 @@ func init() {
 	mailSendCmd.Flags().StringVar(&mailReplyTo, "reply-to", "", "Message ID this is replying to")
 	mailSendCmd.Flags().BoolVarP(&mailNotify, "notify", "n", false, "Send tmux notification to recipient")
 	mailSendCmd.Flags().BoolVar(&mailPinned, "pinned", false, "Pin message (for handoff context that persists)")
+	mailSendCmd.Flags().BoolVar(&mailEphemeral, "ephemeral", false, "Send as ephemeral wisp (auto-cleanup on patrol squash)")
 	mailSendCmd.Flags().BoolVar(&mailSendSelf, "self", false, "Send to self (auto-detect from cwd)")
 	_ = mailSendCmd.MarkFlagRequired("subject")
 
@@ -332,6 +334,9 @@ func runMailSend(cmd *cobra.Command, args []string) error {
 	// Set pinned flag
 	msg.Pinned = mailPinned
 
+	// Set ephemeral flag
+	msg.Ephemeral = mailEphemeral
+
 	// Handle reply-to: auto-set type to reply and look up thread
 	if mailReplyTo != "" {
 		msg.ReplyTo = mailReplyTo
@@ -434,8 +439,12 @@ func runMailInbox(cmd *cobra.Command, args []string) error {
 		if msg.Priority == mail.PriorityHigh || msg.Priority == mail.PriorityUrgent {
 			priorityMarker = " " + style.Bold.Render("!")
 		}
+		ephemeralMarker := ""
+		if msg.Ephemeral || msg.Source == mail.SourceWisp {
+			ephemeralMarker = " " + style.Dim.Render("(ephemeral)")
+		}
 
-		fmt.Printf("  %s %s%s%s\n", readMarker, msg.Subject, typeMarker, priorityMarker)
+		fmt.Printf("  %s %s%s%s%s\n", readMarker, msg.Subject, typeMarker, priorityMarker, ephemeralMarker)
 		fmt.Printf("    %s from %s\n",
 			style.Dim.Render(msg.ID),
 			msg.From)
diff --git a/internal/cmd/spawn.go b/internal/cmd/spawn.go
index 05d828c8..b8ac741c 100644
--- a/internal/cmd/spawn.go
+++ b/internal/cmd/spawn.go
@@ -395,13 +395,14 @@ func runSpawn(cmd *cobra.Command, args []string) error {
 	sender := detectSender()
 	sessionName := sessMgr.SessionName(polecatName)
 
-	// Notify Witness with POLECAT_STARTED message
+	// Notify Witness with POLECAT_STARTED message (ephemeral - lifecycle ping)
 	witnessAddr := fmt.Sprintf("%s/witness", rigName)
 	witnessNotification := &mail.Message{
-		To:      witnessAddr,
-		From:    sender,
-		Subject: fmt.Sprintf("POLECAT_STARTED %s", polecatName),
-		Body:    fmt.Sprintf("Issue: %s\nSession: %s", assignmentID, sessionName),
+		To:        witnessAddr,
+		From:      sender,
+		Subject:   fmt.Sprintf("POLECAT_STARTED %s", polecatName),
+		Body:      fmt.Sprintf("Issue: %s\nSession: %s", assignmentID, sessionName),
+		Ephemeral: true,
 	}
 
 	if err := townRouter.Send(witnessNotification); err != nil {
@@ -410,13 +411,14 @@ func runSpawn(cmd *cobra.Command, args []string) error {
 		fmt.Printf("  %s\n", style.Dim.Render("Witness notified of polecat start"))
 	}
 
-	// Notify Deacon with POLECAT_STARTED message (includes full rig/polecat address)
+	// Notify Deacon with POLECAT_STARTED message (ephemeral - lifecycle ping)
 	deaconAddr := "deacon/"
 	deaconNotification := &mail.Message{
-		To:      deaconAddr,
-		From:    sender,
-		Subject: fmt.Sprintf("POLECAT_STARTED %s/%s", rigName, polecatName),
-		Body:    fmt.Sprintf("Issue: %s\nSession: %s", assignmentID, sessionName),
+		To:        deaconAddr,
+		From:      sender,
+		Subject:   fmt.Sprintf("POLECAT_STARTED %s/%s", rigName, polecatName),
+		Body:      fmt.Sprintf("Issue: %s\nSession: %s", assignmentID, sessionName),
+		Ephemeral: true,
 	}
 
 	if err := townRouter.Send(deaconNotification); err != nil {
diff --git a/internal/mail/mailbox.go b/internal/mail/mailbox.go
index 58a36b77..8a5bb596 100644
--- a/internal/mail/mailbox.go
+++ b/internal/mail/mailbox.go
@@ -23,6 +23,7 @@ type Mailbox struct {
 	identity string // beads identity (e.g., "gastown/polecats/Toast")
 	workDir  string // directory to run bd commands in
 	beadsDir string // explicit .beads directory path (set via BEADS_DIR)
+	wispDir  string // .beads-wisp directory for ephemeral messages
 	path     string // for legacy JSONL mode (crew workers)
 	legacy   bool   // true = use JSONL files, false = use beads
 }
@@ -48,20 +49,26 @@ func NewMailboxBeads(identity, workDir string) *Mailbox {
 // NewMailboxFromAddress creates a beads-backed mailbox from a GGT address.
 func NewMailboxFromAddress(address, workDir string) *Mailbox {
 	beadsDir := filepath.Join(workDir, ".beads")
+	// Wisp directory is .beads-wisp/.beads (bd init creates .beads/ subdirectory)
+	wispDir := filepath.Join(workDir, ".beads-wisp", ".beads")
 	return &Mailbox{
 		identity: addressToIdentity(address),
 		workDir:  workDir,
 		beadsDir: beadsDir,
+		wispDir:  wispDir,
 		legacy:   false,
 	}
 }
 
 // NewMailboxWithBeadsDir creates a mailbox with an explicit beads directory.
 func NewMailboxWithBeadsDir(address, workDir, beadsDir string) *Mailbox {
+	// Derive wispDir from beadsDir (.beads-wisp/.beads sibling structure)
+	wispDir := filepath.Join(filepath.Dir(beadsDir), ".beads-wisp", ".beads")
 	return &Mailbox{
 		identity: addressToIdentity(address),
 		workDir:  workDir,
 		beadsDir: beadsDir,
+		wispDir:  wispDir,
 		legacy:   false,
 	}
 }
@@ -85,6 +92,29 @@ func (m *Mailbox) List() ([]*Message, error) {
 }
 
 func (m *Mailbox) listBeads() ([]*Message, error) {
+	// Query persistent beads
+	persistentMsgs, err := m.listFromDir(m.beadsDir, SourcePersistent)
+	if err != nil {
+		return nil, err
+	}
+
+	// Query wisp beads (ignore errors for missing dir)
+	var wispMsgs []*Message
+	if m.wispDir != "" {
+		wispMsgs, _ = m.listFromDir(m.wispDir, SourceWisp)
+	}
+
+	// Merge and sort by timestamp (newest first)
+	all := append(persistentMsgs, wispMsgs...)
+	sort.Slice(all, func(i, j int) bool {
+		return all[i].Timestamp.After(all[j].Timestamp)
+	})
+
+	return all, nil
+}
+
+// listFromDir queries messages from a specific beads directory.
+func (m *Mailbox) listFromDir(beadsDir string, source MessageSource) ([]*Message, error) {
 	// bd list --type=message --assignee=<identity> --json --status=open
 	cmd := exec.Command("bd", "list",
 		"--type", "message",
@@ -94,7 +124,7 @@ func (m *Mailbox) listBeads() ([]*Message, error) {
 	)
 	cmd.Dir = m.workDir
 	cmd.Env = append(cmd.Environ(),
-		"BEADS_DIR="+m.beadsDir,
+		"BEADS_DIR="+beadsDir,
 	)
 
 	var stdout, stderr bytes.Buffer
@@ -119,10 +149,13 @@ func (m *Mailbox) listBeads() ([]*Message, error) {
 		return nil, err
 	}
 
-	// Convert to GGT messages
+	// Convert to GGT messages and set source
 	var messages []*Message
 	for _, bm := range beadsMsgs {
-		messages = append(messages, bm.ToMessage())
+		msg := bm.ToMessage()
+		msg.Source = source
+		msg.Ephemeral = (source == SourceWisp)
+		messages = append(messages, msg)
 	}
 
 	return messages, nil
@@ -193,9 +226,28 @@ func (m *Mailbox) Get(id string) (*Message, error) {
 }
 
 func (m *Mailbox) getBeads(id string) (*Message, error) {
+	// Try persistent first
+	msg, err := m.getFromDir(id, m.beadsDir, SourcePersistent)
+	if err == nil {
+		return msg, nil
+	}
+
+	// Try wisp storage
+	if m.wispDir != "" {
+		msg, err = m.getFromDir(id, m.wispDir, SourceWisp)
+		if err == nil {
+			return msg, nil
+		}
+	}
+
+	return nil, ErrMessageNotFound
+}
+
+// getFromDir retrieves a message from a specific beads directory.
+func (m *Mailbox) getFromDir(id, beadsDir string, source MessageSource) (*Message, error) {
 	cmd := exec.Command("bd", "show", id, "--json")
 	cmd.Dir = m.workDir
-	cmd.Env = append(cmd.Environ(), "BEADS_DIR="+m.beadsDir)
+	cmd.Env = append(cmd.Environ(), "BEADS_DIR="+beadsDir)
 
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -221,7 +273,10 @@ func (m *Mailbox) getBeads(id string) (*Message, error) {
 		return nil, ErrMessageNotFound
 	}
 
-	return bms[0].ToMessage(), nil
+	msg := bms[0].ToMessage()
+	msg.Source = source
+	msg.Ephemeral = (source == SourceWisp)
+	return msg, nil
 }
 
 func (m *Mailbox) getLegacy(id string) (*Message, error) {
@@ -246,9 +301,28 @@ func (m *Mailbox) MarkRead(id string) error {
 }
 
 func (m *Mailbox) markReadBeads(id string) error {
+	// Try persistent first
+	err := m.closeInDir(id, m.beadsDir)
+	if err == nil {
+		return nil
+	}
+
+	// Try wisp storage
+	if m.wispDir != "" {
+		err = m.closeInDir(id, m.wispDir)
+		if err == nil {
+			return nil
+		}
+	}
+
+	return ErrMessageNotFound
+}
+
+// closeInDir closes a message in a specific beads directory.
+func (m *Mailbox) closeInDir(id, beadsDir string) error {
 	cmd := exec.Command("bd", "close", id)
 	cmd.Dir = m.workDir
-	cmd.Env = append(cmd.Environ(), "BEADS_DIR="+m.beadsDir)
+	cmd.Env = append(cmd.Environ(), "BEADS_DIR="+beadsDir)
 
 	var stderr bytes.Buffer
 	cmd.Stderr = &stderr
diff --git a/internal/mail/router.go b/internal/mail/router.go
index e2481b50..092e5f61 100644
--- a/internal/mail/router.go
+++ b/internal/mail/router.go
@@ -88,6 +88,40 @@ func isTownLevelAddress(address string) bool {
 	return addr == "mayor" || addr == "deacon"
 }
 
+// resolveWispDir returns the .beads-wisp/.beads directory for ephemeral mail.
+// Like resolveBeadsDir, mail wisps use town-level storage.
+// Note: bd init creates .beads/ subdirectory, so the full path is .beads-wisp/.beads
+func (r *Router) resolveWispDir() string {
+	if r.townRoot == "" {
+		return filepath.Join(r.workDir, ".beads-wisp", ".beads")
+	}
+	return filepath.Join(r.townRoot, ".beads-wisp", ".beads")
+}
+
+// shouldBeEphemeral determines if a message should be stored as a wisp.
+// Returns true if:
+// - Message.Ephemeral is explicitly set
+// - Subject matches lifecycle message patterns (POLECAT_*, NUDGE, etc.)
+func (r *Router) shouldBeEphemeral(msg *Message) bool {
+	if msg.Ephemeral {
+		return true
+	}
+	// Auto-detect lifecycle messages by subject prefix
+	subjectLower := strings.ToLower(msg.Subject)
+	ephemeralPrefixes := []string{
+		"polecat_started",
+		"polecat_done",
+		"start_work",
+		"nudge",
+	}
+	for _, prefix := range ephemeralPrefixes {
+		if strings.HasPrefix(subjectLower, prefix) {
+			return true
+		}
+	}
+	return false
+}
+
 // Send delivers a message via beads message.
 // Routes the message to the correct beads database based on recipient address.
 func (r *Router) Send(msg *Message) error {
@@ -120,8 +154,17 @@ func (r *Router) Send(msg *Message) error {
 		args = append(args, "--labels", strings.Join(labels, ","))
 	}
 
-	// Resolve the correct beads directory for the recipient
-	beadsDir := r.resolveBeadsDir(msg.To)
+	// Resolve the correct beads directory based on ephemeral status
+	var beadsDir string
+	if r.shouldBeEphemeral(msg) {
+		beadsDir = r.resolveWispDir()
+		// Ensure wisp directory exists
+		if err := os.MkdirAll(beadsDir, 0755); err != nil {
+			return fmt.Errorf("creating wisp dir: %w", err)
+		}
+	} else {
+		beadsDir = r.resolveBeadsDir(msg.To)
+	}
 
 	cmd := exec.Command("bd", args...)
 	cmd.Env = append(cmd.Environ(),
diff --git a/internal/mail/types.go b/internal/mail/types.go
index ffe2ec25..b3e9e723 100644
--- a/internal/mail/types.go
+++ b/internal/mail/types.go
@@ -28,6 +28,17 @@ const (
 // MessageType indicates the purpose of a message.
 type MessageType string
 
+// MessageSource indicates where a message is stored.
+type MessageSource string
+
+const (
+	// SourcePersistent indicates the message is in permanent .beads storage.
+	SourcePersistent MessageSource = "persistent"
+
+	// SourceWisp indicates the message is in ephemeral .beads-wisp storage.
+	SourceWisp MessageSource = "wisp"
+)
+
 const (
 	// TypeTask indicates a message requiring action from the recipient.
 	TypeTask MessageType = "task"
@@ -97,6 +108,14 @@ type Message struct {
 
 	// Pinned marks the message as pinned (won't be auto-archived).
 	Pinned bool `json:"pinned,omitempty"`
+
+	// Ephemeral marks this as a transient message stored in wisps.
+	// Ephemeral messages auto-cleanup on patrol squash.
+	Ephemeral bool `json:"ephemeral,omitempty"`
+
+	// Source indicates where this message is stored (persistent or wisp).
+	// Set during List(), not serialized.
+	Source MessageSource `json:"-"`
 }
 
 // NewMessage creates a new message with a generated ID and thread ID.