diff --git a/packages/mosaic/framework/tools/tmux/send-message.sh b/packages/mosaic/framework/tools/tmux/send-message.sh
index d397907f..484ca6ce 100755
--- a/packages/mosaic/framework/tools/tmux/send-message.sh
+++ b/packages/mosaic/framework/tools/tmux/send-message.sh
@@ -97,13 +97,34 @@ printf '%s' "$MSG" | "${tmux_cmd[@]}" load-buffer -b "$BUF" -
 #   would otherwise accumulate forever.
 sleep 0.5
 
-# 2) Submit, then POSITIVELY confirm submission; flush with another Enter if it is
-#    still a draft. Success requires positive evidence — the queued banner, OR the
-#    REPL input box located AND clear of our message tail. The historical bug was
-#    treating ABSENCE of a draft as delivery: if the prompt glyph was never matched
-#    (wrong pane / prompt-glyph drift), an unsubmitted message read as "delivered"
-#    and worker->lead relays stalled silently. We now default to UNCONFIRMED and only
-#    upgrade to delivered on positive evidence; anything we cannot confirm fails loud.
+# 2) Submit, then POSITIVELY confirm submission by DRAFT TRANSITION, not by prompt
+#    glyph. The historical bug was treating ABSENCE of a draft as delivery; the
+#    2026-08 fix over-corrected to glyph inference (grep '❯|^>|│ >'), which locates
+#    only Claude Code's box and false-NEGATIVES every glyphless REPL (pi renders a
+#    U+2500 rule, no glyph) — a delivered message reported "UNDELIVERED", driving a
+#    retry that duplicates it. Runtime-agnostic evidence: our message tail sits on
+#    the INPUT line (located by the cursor row, not a glyph) BEFORE Enter, and has
+#    LEFT it AFTER — that transition is positive proof of submission and needs no
+#    glyph. Absence alone still never means delivered: if we never saw our draft on
+#    the input line we stay UNCONFIRMED (wrong/dead pane), and a draft that never
+#    leaves the input line stays a DRAFT (exit 2), preserving both historical guards.
+_cursor_line() { # echo the pane's current input (cursor) line, glyph-free
+  local cy line
+  cy=$("${tmux_cmd[@]}" display-message -p -t "$EFFECTIVE_TARGET" -F '#{cursor_y}' 2>/dev/null) || return 1
+  [ -n "$cy" ] || return 1
+  "${tmux_cmd[@]}" capture-pane -t "$EFFECTIVE_TARGET" -p 2>/dev/null | sed -n "$((cy + 1))p"
+}
+_draft_on_input() { # true iff our message tail is sitting on the input line now
+  [ -n "$snippet" ] || return 1
+  printf '%s' "$(_cursor_line)" | grep -qF "$snippet"
+}
+
+# Baseline: after the paste, our draft must be on the input line. This is positive
+# proof we are on the right pane and the paste landed — the anchor the transition
+# check measures against.
+saw_draft=0
+_draft_on_input && saw_draft=1
+
 status="unconfirmed"
 for attempt in $(seq 1 $((RETRIES + 1))); do
   "${tmux_cmd[@]}" send-keys -t "$EFFECTIVE_TARGET" Enter
@@ -113,20 +134,26 @@ for attempt in $(seq 1 $((RETRIES + 1))); do
   if printf '%s' "$pane" | grep -qF "$QUEUED_RE"; then
     status="queued"; break
   fi
-  # Locate the REPL input box (prompt glyph). If we cannot see it, we have NO
-  # evidence of submission state — stay UNCONFIRMED and retry; never infer delivery.
+  # POSITIVE draft evidence from a located prompt box, when one exists. This is the
+  # cursor-row check's blind spot: a pane in COOKED mode (a plain shell whose
+  # foreground process never reads stdin) echoes our paste via the kernel line
+  # discipline and moves the cursor off it on Enter, which is indistinguishable from
+  # a real submit by cursor row alone. If a prompt box IS locatable and still carries
+  # our tail, that is affirmative proof the message was not consumed. Absence of a
+  # glyph is still never used for anything — that inference is the original E7 bug.
   promptline=$(printf '%s' "$pane" | grep -E '❯|^>|│ >' | tail -1)
-  if [ -z "$promptline" ]; then
-    status="unconfirmed"; continue
-  fi
-  # Input box located AND still carrying our tail => unsubmitted draft. Flush + retry.
-  # (Submitted messages scroll up into history; a draft stays on the ❯ line.)
-  if [ -n "$snippet" ] && printf '%s' "$promptline" | grep -qF "$snippet"; then
+  if [ -n "$promptline" ] && [ -n "$snippet" ] && printf '%s' "$promptline" | grep -qF "$snippet"; then
     status="draft"; continue
   fi
-  # Input box located AND clear of our tail => positively submitted. This is the
-  # only path to success besides the queued banner.
-  status="delivered"; break
+  if [ "$saw_draft" = 1 ]; then
+    if _draft_on_input; then
+      status="draft"; continue      # still on the input line => not submitted; flush + retry
+    fi
+    status="delivered"; break        # left the input line => positively submitted
+  fi
+  # No confirmed baseline yet: try to (re)acquire it; never infer delivery from absence.
+  if _draft_on_input; then saw_draft=1; status="draft"; continue; fi
+  status="unconfirmed"; continue
 done
 
 [ "$VERBOSE" = 1 ] && { echo "--- pane tail ($TARGET) ---"; printf '%s\n' "$pane" | tail -4; echo "---"; }
diff --git a/packages/mosaic/framework/tools/tmux/test-send-message-glyph-agnostic.sh b/packages/mosaic/framework/tools/tmux/test-send-message-glyph-agnostic.sh
new file mode 100755
index 00000000..55d0ac13
--- /dev/null
+++ b/packages/mosaic/framework/tools/tmux/test-send-message-glyph-agnostic.sh
@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+# Red-first regression test for E7 (#1017 task 2): the confirm-check must bind
+# "delivered" to WHETHER THE MESSAGE WAS SUBMITTED, not to which runtime's prompt
+# glyph is present. A pi seat renders a U+2500 rule input box with no ❯/^>/│ >
+# glyph; send-message.sh:118 locates the box only by glyph, so a genuinely
+# delivered message on a glyphless REPL falsely reports exit 2 "may be UNDELIVERED",
+# and the operator's rc=2-driven retry duplicates it.
+#
+# Parameterized on $SEND: RED against the shipping blob (B and D fail), GREEN
+# against a candidate patch. No pi; no fake HOME; hermetic throwaway socket.
+#
+# Submission counting is EXACT and terminal-echo-independent: the fixture message
+# is `echo <tok> >>SINK`; each real submission appends one line. wc -l SINK ==
+# number of times the REPL actually executed the send. This does not depend on how
+# many times the marker string is painted on screen.
+set -u
+SEND="${SEND:?set SEND=/path/to/send-message.sh}"
+SOCKET="glyphagnostic-$$"
+TMP="$(mktemp -d)"
+tmux() { command tmux -L "$SOCKET" "$@"; }
+cleanup() { command tmux -L "$SOCKET" kill-server 2>/dev/null; rm -rf "$TMP"; }
+trap cleanup EXIT
+pass=0; fail=0
+ok() { printf 'ok   %s\n' "$1"; pass=$((pass+1)); }
+no() { printf 'FAIL %s -- %s\n' "$1" "$2"; fail=$((fail+1)); }
+
+mk() { tmux new-session -d -s "$1" -x 120 -y 40 -c "$TMP" "PS1='$2' exec bash --noprofile --norc -i"; sleep 0.5; }
+subs() { [ -f "$1" ] && wc -l <"$1" | tr -d ' ' || echo 0; }  # exact submission count
+
+echo "SEND=$SEND    tmux $(command tmux -V | awk '{print $2}')"
+
+# --- A (control): glyph box (❯) that submits => exit 0, exactly one submission.
+mk ctl '❯ '
+SINK="$TMP/sink.ctl"
+out=$("$SEND" -L "$SOCKET" -t ctl -m "echo x >>'$SINK'" 2>"$TMP/e.ctl"); rc=$?; sleep 0.4
+if [ "$rc" = 0 ] && [ "$(subs "$SINK")" = 1 ]; then
+  ok "control: ❯-box submits => exit 0, exactly one submission"
+else no "control: ❯-box submits => exit 0, one submission" "rc=$rc subs=$(subs "$SINK") err=[$(cat "$TMP/e.ctl")]"; fi
+
+# --- B (THE false-rc regression): glyphless U+2500 box that SUBMITS. Message lands
+#     (subs==1) yet shipping reports exit 2. Must be exit 0.
+mk sub $'──────── \n'
+SINK="$TMP/sink.sub"
+out=$("$SEND" -L "$SOCKET" -t sub -m "echo x >>'$SINK'" 2>"$TMP/e.sub"); rc=$?; sleep 0.4
+if [ "$rc" = 0 ] && [ "$(subs "$SINK")" = 1 ]; then
+  ok "glyphless: U+2500 box that submits => exit 0 (delivered, not 'UNDELIVERED')"
+else no "glyphless: U+2500 box that submits => exit 0" \
+        "rc=$rc subs=$(subs "$SINK")(delivered=$([ "$(subs "$SINK")" -ge 1 ] && echo yes||echo no)) err=[$(cat "$TMP/e.sub")]"; fi
+
+# --- D (duplicate arm): operator follows the rc=2 stderr and retries once. On the
+#     glyphless box, shipping => two submissions (the reported duplicate). The
+#     property: one logical send => exactly one submission. Same fix closes it.
+mk dup $'──────── \n'
+SINK="$TMP/sink.dup"
+tries=0
+for attempt in 1 2; do
+  tries=$((tries+1))
+  out=$("$SEND" -L "$SOCKET" -t dup -m "echo x >>'$SINK'" 2>/dev/null); rc=$?
+  sleep 0.4
+  [ "$rc" = 0 ] && break   # operator stops retrying only when told delivered
+done
+if [ "$(subs "$SINK")" = 1 ]; then
+  ok "duplicate: one logical send (rc-driven retry) => exactly one submission (tries=$tries)"
+else no "duplicate: one logical send => exactly one submission" "submissions=$(subs "$SINK") tries=$tries"; fi
+
+# --- E (faithful hung managed TUI, NOT a cooked shell): raw/no-echo, paints nothing.
+#     A cooked `sleep infinity` echoes the paste via the kernel line discipline and
+#     false-passes a cursor-row fix that is correct on real seats (measured). So: raw.
+mk_rawstuck() { tmux new-session -d -s "$1" -x 120 -y 40 -c "$TMP" \
+  "bash --noprofile --norc -c 'stty -echo -icanon min 1 time 0 2>/dev/null; exec sleep infinity'"; sleep 0.5; }
+mk_rawstuck estuck
+SINK="$TMP/sink.estuck"
+out=$("$SEND" -L "$SOCKET" -t estuck -r 1 -m "this stuck draft was never submitted" 2>/dev/null); rc=$?
+sleep 0.3
+if [ "$rc" != 0 ] && [ "$(subs "$SINK")" = 0 ]; then
+  ok "raw/no-echo stuck TUI (not submitted) => non-zero (no false delivered)"
+else no "raw stuck TUI must NOT report delivered" "rc=$rc subs=$(subs "$SINK")"; fi
+
+# --- F (busy/queued branch, your BUSY-not-runtime finding): glyphless pane rendering the
+#     queued banner, never consuming. QUEUED_RE :113 fires before the glyph grep => rc=0.
+mk_busy() { tmux new-session -d -s "$1" -x 120 -y 40 -c "$TMP" \
+  "bash --noprofile --norc -c 'printf \"Press up to edit queued messages\n\"; exec sleep infinity'"; sleep 0.5; }
+mk_busy ebusy
+SINK="$TMP/sink.ebusy"
+out=$("$SEND" -L "$SOCKET" -t ebusy -m "echo x >>'$SINK'" 2>/dev/null); rc=$?; sleep 0.3
+if [ "$rc" = 0 ]; then
+  ok "busy/queued-banner glyphless => exit 0 (queued is delivery; runtime owns custody)"
+else no "busy/queued-banner must report delivered" "rc=$rc"; fi
+
+# --- C (historical-bug guard): unresolvable target. No pane ever carried our draft
+#     => must fail, never infer delivered from absence of a glyph/snippet.
+if out=$("$SEND" -L "$SOCKET" -t "nonexistent-$$" -m "echo x >>'$TMP/sink.wrong'" 2>/dev/null); then
+  no "wrong-pane: unresolvable target must NOT report success" "expected non-zero, got 0"
+else ok "wrong-pane: unresolvable target => non-zero (no false delivered)"; fi
+
+echo "---"; echo "pass=$pass fail=$fail"
+[ "$fail" = 0 ]
diff --git a/packages/mosaic/framework/tools/tmux/test-send-message-verdict.sh b/packages/mosaic/framework/tools/tmux/test-send-message-verdict.sh
index b1f9bbfe..4291dbc4 100755
--- a/packages/mosaic/framework/tools/tmux/test-send-message-verdict.sh
+++ b/packages/mosaic/framework/tools/tmux/test-send-message-verdict.sh
@@ -4,10 +4,13 @@
 #
 #   1. DELIVERED   — a REPL that renders a `❯ ` input box and submits on Enter
 #                    (text scrolls to history, box clears) => exit 0 "✓ delivered".
-#   2. UNCONFIRMED — a pane with NO locatable prompt glyph. This is the exact
-#                    historical FALSE POSITIVE: pre-patch it printed "✓ delivered"
-#                    exit 0; post-patch it MUST fail loud (exit 2, stderr
-#                    "could not confirm submission").
+#   2. DELIVERED   — a pane with NO prompt glyph that DOES submit => exit 0. A pi
+#                    seat is this fixture (U+2500 rule, no glyph). Reshaped for
+#                    #1257; see the note at the fixture for why the old exit-2
+#                    assertion was wrong.
+#   2b. UNCONFIRMED— a glyphless pane that never submits (raw/no-echo hung TUI)
+#                    => must fail loud. This carries the historical
+#                    false-positive guard that fixture 2 used to be credited with.
 #   3. DRAFT       — a `❯ `-prompt pane that never submits (message stays on the
 #                    input line) => exit 2, stderr "unsubmitted draft".
 set -uo pipefail
@@ -37,19 +40,44 @@ else
   no "delivered: ❯-prompt REPL that submits => exit 0 ✓ delivered" "rc=$rc out=[$out] err=[$(cat "$TMP/e1")]"
 fi
 
-# --- Fixture 2: NO prompt glyph (default bash PS1). THE regression: pre-patch this
-#     was a silent false-positive "delivered"; post-patch it must be unconfirmed→exit 2.
+# --- Fixture 2: NO prompt glyph, and the pane DOES submit (interactive bash).
+#     RESHAPED 2026-08-16 (#1257), deliberately. This fixture previously asserted
+#     exit 2 here and was labelled "false-positive FIXED". That assertion was wrong,
+#     and locking it in is what kept E7 alive: the pane submits, so "delivered" is
+#     the truth, and a pi seat — whose input box is a bare U+2500 rule with no glyph
+#     — IS this fixture. Reporting exit 2 for it told operators a delivered message
+#     may be undelivered, and the retry that advice invites is the duplicate.
+#
+#     The guard this fixture was reaching for is real and is NOT dropped: "never
+#     infer delivered from absence" is now enforced positively by fixture 2b below
+#     (glyphless AND not submitting => must fail) and by fixture 3 (locatable box
+#     still carrying our tail => draft). Absence alone decides nothing either way.
 tmux -L "$SOCKET" new-session -d -s noglyph -c "$TMP" \
   'PS1="sh-noglyph$ " exec bash --noprofile --norc -i'
 sleep 0.3
-if out=$("$SEND" -L "$SOCKET" -t "=noglyph" -m "verdict fixture two must fail loud" 2>"$TMP/e2"); then
-  no "unconfirmed: glyphless pane must NOT report success" "expected exit 2, got 0 (out=[$out])"
+out=$("$SEND" -L "$SOCKET" -t "=noglyph" -m "verdict fixture two must fail loud" 2>"$TMP/e2"); rc=$?
+if [ "$rc" -eq 0 ] && printf '%s' "$out" | grep -qF "✓ delivered"; then
+  ok "delivered: glyphless pane that submits => exit 0 (runtime-agnostic, E7 FIXED)"
+else
+  no "delivered: glyphless pane that submits => exit 0" "rc=$rc out=[$out] err=[$(cat "$TMP/e2")]"
+fi
+
+# --- Fixture 2b: NO prompt glyph AND never submits — a hung managed TUI holding the
+#     terminal in raw/no-echo, which is what a stuck agent seat actually is (measured
+#     on live pi: stty -echo -icanon). Nothing is echoed, nothing is consumed, so
+#     there is no positive evidence of submission and the tool MUST fail loud. This
+#     is the historical false-positive guard, kept as a positive test.
+tmux -L "$SOCKET" new-session -d -s rawstuck -c "$TMP" \
+  'bash --noprofile --norc -c "stty -echo -icanon min 1 time 0 2>/dev/null; exec sleep infinity"'
+sleep 0.3
+if out=$("$SEND" -L "$SOCKET" -t "=rawstuck" -r 1 -m "verdict fixture two-b never submitted" 2>"$TMP/e2b"); then
+  no "unconfirmed: glyphless hung TUI must NOT report success" "expected non-zero, got 0 (out=[$out])"
 else
   rc=$?
-  if [ "$rc" -eq 2 ] && grep -qF "could not confirm submission" "$TMP/e2"; then
-    ok "unconfirmed: glyphless pane => exit 2 + 'could not confirm submission' (false-positive FIXED)"
+  if [ "$rc" -ne 0 ] && grep -qF "could not confirm submission" "$TMP/e2b"; then
+    ok "unconfirmed: glyphless hung TUI (raw/no-echo) => non-zero + 'could not confirm submission'"
   else
-    no "unconfirmed: glyphless pane => exit 2 + stderr" "rc=$rc err=[$(cat "$TMP/e2")]"
+    no "unconfirmed: glyphless hung TUI => non-zero + stderr" "rc=$rc err=[$(cat "$TMP/e2b")]"
   fi
 fi