diff --git a/internal/tmux/tmux.go b/internal/tmux/tmux.go
index afa03fd0..117beacb 100644
--- a/internal/tmux/tmux.go
+++ b/internal/tmux/tmux.go
@@ -281,7 +281,7 @@ func (t *Tmux) SendKeysDelayedDebounced(session, keys string, preDelayMs, deboun
 
 // NudgeSession sends a message to a Claude Code session reliably.
 // This is the canonical way to send messages to Claude sessions.
-// Uses: literal mode + 500ms debounce + separate Enter.
+// Uses: literal mode + 500ms debounce + ESC (for vim mode) + separate Enter.
 // Verification is the Witness's job (AI), not this function.
 func (t *Tmux) NudgeSession(session, message string) error {
 	// 1. Send text in literal mode (handles special characters)
@@ -292,7 +292,12 @@ func (t *Tmux) NudgeSession(session, message string) error {
 	// 2. Wait 500ms for paste to complete (tested, required)
 	time.Sleep(500 * time.Millisecond)
 
-	// 3. Send Enter with retry (critical for message submission)
+	// 3. Send Escape to exit vim INSERT mode if enabled (harmless in normal mode)
+	// See: https://github.com/anthropics/gastown/issues/307
+	_, _ = t.run("send-keys", "-t", session, "Escape")
+	time.Sleep(100 * time.Millisecond)
+
+	// 4. Send Enter with retry (critical for message submission)
 	var lastErr error
 	for attempt := 0; attempt < 3; attempt++ {
 		if attempt > 0 {
@@ -318,7 +323,12 @@ func (t *Tmux) NudgePane(pane, message string) error {
 	// 2. Wait 500ms for paste to complete (tested, required)
 	time.Sleep(500 * time.Millisecond)
 
-	// 3. Send Enter with retry (critical for message submission)
+	// 3. Send Escape to exit vim INSERT mode if enabled (harmless in normal mode)
+	// See: https://github.com/anthropics/gastown/issues/307
+	_, _ = t.run("send-keys", "-t", pane, "Escape")
+	time.Sleep(100 * time.Millisecond)
+
+	// 4. Send Enter with retry (critical for message submission)
 	var lastErr error
 	for attempt := 0; attempt < 3; attempt++ {
 		if attempt > 0 {