diff --git a/bin/fm-send.sh b/bin/fm-send.sh
index 8e651ca..1af1ea5 100755
--- a/bin/fm-send.sh
+++ b/bin/fm-send.sh
@@ -65,5 +65,9 @@ else
       echo "error: text not sent to $T (tmux send-keys failed)" >&2
       exit 1
       ;;
+    busy)
+      echo "error: text not sent to $T (target pane busy)" >&2
+      exit 1
+      ;;
   esac
 fi
diff --git a/bin/fm-spawn.sh b/bin/fm-spawn.sh
index 452d503..4014a1e 100755
--- a/bin/fm-spawn.sh
+++ b/bin/fm-spawn.sh
@@ -35,6 +35,8 @@ STATE="${FM_STATE_OVERRIDE:-$FM_HOME/state}"
 DATA="${FM_DATA_OVERRIDE:-$FM_HOME/data}"
 PROJECTS="${FM_PROJECTS_OVERRIDE:-$FM_HOME/projects}"
 SUB_HOME_MARKER=".fm-secondmate-home"
+# shellcheck source=bin/fm-tmux-lib.sh
+. "$SCRIPT_DIR/fm-tmux-lib.sh"
 # Skip the watcher guard when re-exec'd for one pair of a batch (FM_SPAWN_NO_GUARD is
 # set by the batch loop below), so the guard runs once for the batch, not once per pair.
 [ -n "${FM_SPAWN_NO_GUARD:-}" ] || "$FM_ROOT/bin/fm-guard.sh" || true
@@ -344,6 +346,16 @@ if [ "$KIND" != secondmate ]; then
     echo "error: treehouse get did not enter a worktree within 60s; inspect window $T" >&2
     exit 1
   fi
+  # cwd can flip before the new shell has drawn a prompt. Wait briefly for a
+  # readable idle/busy line before typing the agent launch, otherwise the launch
+  # text can be swallowed during the treehouse handoff while spawn still reports
+  # success.
+  for _ in $(seq 1 20); do
+    state=$(fm_tmux_composer_state "$T")
+    [ "$state" = empty ] && break
+    fm_pane_is_busy "$T" && break
+    sleep 0.2
+  done
 fi
 
 # Per-harness turn-end hook: a file that touches state/<id>.turn-ended when the
@@ -439,8 +451,20 @@ if [ "$KIND" = secondmate ]; then
   sq_home=$(shell_quote "$PROJ_ABS")
   LAUNCH="FM_ROOT_OVERRIDE= FM_STATE_OVERRIDE= FM_DATA_OVERRIDE= FM_PROJECTS_OVERRIDE= FM_CONFIG_OVERRIDE= FM_HOME=$sq_home $LAUNCH"
 fi
-tmux send-keys -t "$T" -l "$LAUNCH"
-sleep 0.3
-tmux send-keys -t "$T" Enter
+verdict=$(fm_tmux_submit_core "$T" "$LAUNCH" 3 0.4 0.3)
+case "$verdict" in
+  pending)
+    echo "error: launch command was not submitted to $T (Enter swallowed; launch text left in composer)" >&2
+    exit 1
+    ;;
+  send-failed)
+    echo "error: launch command was not sent to $T (tmux send-keys failed)" >&2
+    exit 1
+    ;;
+  busy)
+    echo "error: launch command was not sent to $T (target pane busy)" >&2
+    exit 1
+    ;;
+esac
 
 echo "spawned $ID harness=$HARNESS kind=$KIND mode=$MODE yolo=$YOLO window=$T worktree=$WT"
diff --git a/bin/fm-tmux-lib.sh b/bin/fm-tmux-lib.sh
index 374e358..1cb49d5 100755
--- a/bin/fm-tmux-lib.sh
+++ b/bin/fm-tmux-lib.sh
@@ -136,9 +136,11 @@ fm_tmux_composer_state() {  # <target> -> empty|pending|unknown
      && printf '%s' "$stripped" | grep -qiE "$FM_COMPOSER_IDLE_RE"; then
     printf 'empty'; return 0
   fi
-  # Just a bare prompt glyph = empty composer (idle).
+  # Just a bare prompt glyph = empty composer (idle). Codex uses `›` (U+203A);
+  # missing it caused post-submit idle panes to look pending and report a false
+  # "Enter swallowed" after the dim suggestion text was stripped.
   case "$stripped" in
-    '>'|'❯'|'$'|'%'|'#') printf 'empty'; return 0 ;;
+    '>'|'❯'|'›'|'$'|'%'|'#') printf 'empty'; return 0 ;;
   esac
   # A busy footer landing on the cursor line is not pending input.
   if printf '%s' "$stripped" | grep -qiE "${FM_BUSY_REGEX:-$FM_TMUX_BUSY_REGEX_DEFAULT}"; then
@@ -166,8 +168,10 @@ fm_pane_is_busy() {  # <target>
 # fm_tmux_submit_core: type <text> into <target> ONCE, then submit with Enter,
 # verifying the composer cleared. Retries Enter ONLY — never retypes, because a
 # swallowed Enter leaves our text in the composer and retyping would duplicate
-# it. Echoes the final verdict on stdout (empty|pending|unknown|send-failed) so callers can
+# it. Echoes the final verdict on stdout (empty|pending|unknown|busy|send-failed) so callers can
 # pick their own success policy:
+#   - busy means nothing was typed; steering a pane mid-turn queues text into the
+#     next tool-call composer and creates a false swallowed-Enter diagnosis.
 #   - the daemon clears its buffer only on "empty" (strict: an unknown pane must
 #     not be mistaken for a delivered escalation).
 #   - fm-send fails only on "pending" (lenient: a positively-confirmed swallow),
@@ -186,6 +190,7 @@ fm_tmux_submit_enter_core() {  # <target> <retries> <enter-sleep>
 
 fm_tmux_submit_core() {  # <target> <text> <retries> <enter-sleep> <settle>
   local target=$1 text=$2 retries=$3 sleep_s=$4 settle=$5
+  fm_pane_is_busy "$target" && { printf 'busy'; return 0; }
   tmux send-keys -t "$target" -l "$text" 2>/dev/null || { printf 'send-failed'; return 0; }
   sleep "$settle"
   fm_tmux_submit_enter_core "$target" "$retries" "$sleep_s"
diff --git a/tests/fm-composer-ghost.test.sh b/tests/fm-composer-ghost.test.sh
index c6f2b55..1c12a40 100755
--- a/tests/fm-composer-ghost.test.sh
+++ b/tests/fm-composer-ghost.test.sh
@@ -125,6 +125,22 @@ test_dim_ghost_only_composer_is_not_pending() {
   pass "fm_pane_input_pending: a dim ghost-only composer is NOT pending"
 }
 
+test_codex_bold_prompt_with_dim_suggestion_is_not_pending() {
+  local dir fb capture
+  dir="$TMP_ROOT/codex-bold-ghost"; mkdir -p "$dir"
+  fb=$(make_fake_tmux "$dir")
+  capture="$dir/styled.txt"
+  # Codex idle composer: normal/bold prompt glyph plus a dim suggestion. The
+  # root cause of the false "Enter swallowed" was that ghost stripping left the
+  # prompt glyph `›`, but bare-prompt detection did not know that glyph.
+  printf '\033[1m\xe2\x80\xba\033[0m \033[2mExplain this codebase\033[0m\n' > "$capture"
+  if PATH="$fb:$PATH" FM_FAKE_STYLED="$capture" FM_FAKE_CY=0 \
+     fm_pane_input_pending "fakepane"; then
+    fail "codex bold prompt plus dim suggestion falsely read as pending"
+  fi
+  pass "fm_pane_input_pending: codex bold › plus dim suggestion is NOT pending"
+}
+
 test_dim_ghost_inside_bordered_composer_is_not_pending() {
   local dir fb capture
   dir="$TMP_ROOT/ghost-bordered"; mkdir -p "$dir"
@@ -220,6 +236,7 @@ test_strip_ghost_drops_dim_keeps_normal
 test_strip_ghost_handles_combined_and_boundary_codes
 test_strip_ghost_keeps_colored_text_with_2_payloads
 test_dim_ghost_only_composer_is_not_pending
+test_codex_bold_prompt_with_dim_suggestion_is_not_pending
 test_dim_ghost_inside_bordered_composer_is_not_pending
 test_normal_text_still_pending
 test_colored_text_with_2_payload_still_pending
diff --git a/tests/fm-spawn-send-handshake.test.sh b/tests/fm-spawn-send-handshake.test.sh
new file mode 100755
index 0000000..459851d
--- /dev/null
+++ b/tests/fm-spawn-send-handshake.test.sh
@@ -0,0 +1,188 @@
+#!/usr/bin/env bash
+# Regression coverage for launch/steer submission handshakes.
+set -u
+
+# shellcheck source=tests/lib.sh
+. "$(dirname "${BASH_SOURCE[0]}")/lib.sh"
+
+SPAWN="$ROOT/bin/fm-spawn.sh"
+SEND="$ROOT/bin/fm-send.sh"
+
+TMP_ROOT=$(fm_test_tmproot fm-spawn-send-handshake)
+
+make_submit_fake_tmux() {
+  local dir=$1 fakebin
+  fakebin=$(fm_fakebin "$dir")
+  cat > "$fakebin/tmux" <<'SH'
+#!/usr/bin/env bash
+set -u
+log=${FM_FAKE_TMUX_LOG:?}
+composer=${FM_FAKE_COMPOSER:?}
+case "${1:-}" in
+  display-message)
+    for a in "$@"; do
+      case "$a" in
+        *cursor_y*) printf '0\n'; exit 0 ;;
+        *pane_current_path*) printf '%s\n' "${FM_FAKE_PANE_PATH:-$PWD}"; exit 0 ;;
+        '#S') printf 'firstmate\n'; exit 0 ;;
+      esac
+    done
+    printf 'firstmate\n'; exit 0 ;;
+  capture-pane)
+    if [ "${*: -1}" = "-40" ] || [ -n "${FM_FAKE_BUSY_TAIL:-}" ]; then
+      printf '%s\n' "${FM_FAKE_BUSY_TAIL:-}"
+      exit 0
+    fi
+    cat "$composer"
+    exit 0 ;;
+  send-keys)
+    printf '%s\n' "$*" >> "$log"
+    shift
+    while [ $# -gt 0 ]; do
+      case "$1" in
+        -t) shift 2 ;;
+        -l) shift; printf '%s\n' "$1" > "$composer"; shift ;;
+        Enter)
+          if [ -n "${FM_FAKE_BUSY_AFTER_ENTER:-}" ]; then
+            printf 'Working...\n' > "$composer"
+          else
+            printf '\033[1m\xe2\x80\xba\033[0m \033[2mExplain this codebase\033[0m\n' > "$composer"
+          fi
+          shift ;;
+        *) shift ;;
+      esac
+    done
+    exit 0 ;;
+  list-windows)
+    [ -n "${FM_FAKE_TMUX_WINDOW:-}" ] && printf '%s\n' "$FM_FAKE_TMUX_WINDOW"
+    exit 0 ;;
+esac
+exit 1
+SH
+  chmod +x "$fakebin/tmux"
+  printf '%s\n' "$fakebin"
+}
+
+make_spawn_fake_tmux() {
+  local dir=$1 fakebin
+  fakebin=$(fm_fakebin "$dir")
+  cat > "$fakebin/tmux" <<'SH'
+#!/usr/bin/env bash
+set -u
+log=${FM_FAKE_TMUX_LOG:?}
+composer=${FM_FAKE_COMPOSER:?}
+case "${1:-}" in
+  has-session|new-session|new-window)
+    printf '%s\n' "$*" >> "$log"
+    exit 0 ;;
+  list-windows)
+    exit 0 ;;
+  display-message)
+    for a in "$@"; do
+      case "$a" in
+        *cursor_y*) printf '0\n'; exit 0 ;;
+        *pane_current_path*) printf '%s\n' "${FM_FAKE_WORKTREE:?}"; exit 0 ;;
+      esac
+    done
+    printf 'firstmate\n'; exit 0 ;;
+  capture-pane)
+    cat "$composer"
+    exit 0 ;;
+  send-keys)
+    printf '%s\n' "$*" >> "$log"
+    shift
+    while [ $# -gt 0 ]; do
+      case "$1" in
+        -t) shift 2 ;;
+        -l) shift; printf '%s\n' "$1" > "$composer"; touch "${FM_FAKE_LAUNCH_TYPED:-/dev/null}"; shift ;;
+        Enter)
+          if [ -n "${FM_FAKE_LAUNCH_TYPED:-}" ] && [ -e "$FM_FAKE_LAUNCH_TYPED" ] && [ -z "${FM_FAKE_KEEP_LAUNCH_PENDING:-}" ]; then
+            printf 'Working...\n' > "$composer"
+          fi
+          shift ;;
+        *) shift ;;
+      esac
+    done
+    exit 0 ;;
+esac
+exit 1
+SH
+  cat > "$fakebin/treehouse" <<'SH'
+#!/usr/bin/env bash
+exit 0
+SH
+  chmod +x "$fakebin/tmux" "$fakebin/treehouse"
+  printf '%s\n' "$fakebin"
+}
+
+test_fm_send_accepts_codex_idle_prompt_after_submit() {
+  local dir home fakebin log composer err
+  dir="$TMP_ROOT/send-codex-idle"; mkdir -p "$dir"
+  home="$dir/home"; mkdir -p "$home/state"
+  log="$dir/tmux.log"; composer="$dir/composer"; err="$dir/send.err"
+  printf '\033[1m\xe2\x80\xba\033[0m \033[2mExplain this codebase\033[0m\n' > "$composer"
+  fakebin=$(make_submit_fake_tmux "$dir")
+  PATH="$fakebin:$PATH" FM_HOME="$home" FM_FAKE_TMUX_LOG="$log" FM_FAKE_COMPOSER="$composer" \
+    FM_SEND_SLEEP=0.01 "$SEND" sess:win 'route this work' >/dev/null 2>"$err" \
+    || fail "fm-send reported a false swallowed Enter on codex idle prompt: $(cat "$err")"
+  pass "fm-send accepts codex idle/ghost prompt as submitted"
+}
+
+test_fm_send_refuses_busy_pane_without_typing() {
+  local dir home fakebin log composer err
+  dir="$TMP_ROOT/send-busy"; mkdir -p "$dir"
+  home="$dir/home"; mkdir -p "$home/state"
+  log="$dir/tmux.log"; composer="$dir/composer"; err="$dir/send.err"
+  : > "$log"
+  printf '\033[1m\xe2\x80\xba\033[0m\n' > "$composer"
+  fakebin=$(make_submit_fake_tmux "$dir")
+  if PATH="$fakebin:$PATH" FM_HOME="$home" FM_FAKE_TMUX_LOG="$log" FM_FAKE_COMPOSER="$composer" \
+    FM_FAKE_BUSY_TAIL="esc to interrupt" FM_SEND_SLEEP=0.01 \
+    "$SEND" sess:win 'do not queue this while busy' >/dev/null 2>"$err"; then
+    fail "fm-send exited zero for a busy pane"
+  fi
+  assert_contains "$(cat "$err")" "target pane busy" "fm-send did not explain busy target refusal"
+  assert_not_contains "$(cat "$log")" "send-keys -t sess:win -l" "fm-send typed steering text into a busy pane"
+  pass "fm-send refuses a busy pane without typing into the composer"
+}
+
+test_fm_spawn_refuses_success_when_launch_text_remains_pending() {
+  local dir home project worktree fakebin log composer err out status
+  dir="$TMP_ROOT/spawn-pending"; home="$dir/home"; project="$home/projects/alpha"; worktree="$dir/worktree"
+  mkdir -p "$home/data/spawn-pending" "$home/state" "$project" "$worktree"
+  fm_git_init_commit "$worktree"
+  printf 'brief\n' > "$home/data/spawn-pending/brief.md"
+  log="$dir/tmux.log"; composer="$dir/composer"; err="$dir/spawn.err"; out="$dir/spawn.out"
+  : > "$composer"
+  fakebin=$(make_spawn_fake_tmux "$dir")
+  PATH="$fakebin:$PATH" FM_HOME="$home" FM_FAKE_TMUX_LOG="$log" FM_FAKE_COMPOSER="$composer" \
+    FM_FAKE_WORKTREE="$worktree" FM_FAKE_LAUNCH_TYPED="$dir/launch-typed" FM_FAKE_KEEP_LAUNCH_PENDING=1 \
+    "$SPAWN" spawn-pending projects/alpha codex >"$out" 2>"$err"
+  status=$?
+  [ "$status" -ne 0 ] || fail "fm-spawn printed success while launch text was still pending"
+  assert_not_contains "$(cat "$out")" "spawned spawn-pending" "fm-spawn reported spawned despite pending launch"
+  assert_contains "$(cat "$err")" "launch command was not submitted" "fm-spawn did not explain pending launch text"
+  pass "fm-spawn fails instead of reporting success when launch submission stays pending"
+}
+
+test_fm_spawn_reports_success_when_launch_submits_and_pane_busy() {
+  local dir home project worktree fakebin log composer err out
+  dir="$TMP_ROOT/spawn-busy"; home="$dir/home"; project="$home/projects/alpha"; worktree="$dir/worktree"
+  mkdir -p "$home/data/spawn-busy" "$home/state" "$project" "$worktree"
+  fm_git_init_commit "$worktree"
+  printf 'brief\n' > "$home/data/spawn-busy/brief.md"
+  log="$dir/tmux.log"; composer="$dir/composer"; err="$dir/spawn.err"; out="$dir/spawn.out"
+  : > "$composer"
+  fakebin=$(make_spawn_fake_tmux "$dir")
+  PATH="$fakebin:$PATH" FM_HOME="$home" FM_FAKE_TMUX_LOG="$log" FM_FAKE_COMPOSER="$composer" \
+    FM_FAKE_WORKTREE="$worktree" FM_FAKE_LAUNCH_TYPED="$dir/launch-typed" \
+    "$SPAWN" spawn-busy projects/alpha codex >"$out" 2>"$err" \
+    || fail "fm-spawn failed after launch submission made pane busy: $(cat "$err")"
+  assert_contains "$(cat "$out")" "spawned spawn-busy" "fm-spawn did not report success after busy launch"
+  pass "fm-spawn reports success after launch command submits and pane is busy"
+}
+
+test_fm_send_accepts_codex_idle_prompt_after_submit
+test_fm_send_refuses_busy_pane_without_typing
+test_fm_spawn_refuses_success_when_launch_text_remains_pending
+test_fm_spawn_reports_success_when_launch_submits_and_pane_busy