kunchenguid · kunchenguid · Aug 4, 2026 · Aug 4, 2026 · Aug 4, 2026 · Aug 4, 2026
diff --git a/AGENTS.md b/AGENTS.md
@@ -91,7 +91,7 @@ state/               volatile runtime signals; gitignored
   <id>.turn-ended    touched by turn-end hooks
   <id>.grok-turnend-token   firstmate-owned grok hook registry token for the task; removed by teardown
   <id>.kimi-turnend-token   firstmate-owned Kimi hook registry token for the task; removed by teardown
-  <id>.meta          written by fm-spawn: window=, endpoint_task_id=, worktree=, project=, harness=, model=, effort=, kind=, mode=, yolo=, tasktmp=; an optional traceparent= only when trace context is enabled (docs/configuration.md "Trace context propagation"); kind=secondmate also records home= and projects=, plus remote_host=/remote_root=/remote_backend=/remote_target= for a remote route; a non-default runtime backend records further backend-specific fields (docs/configuration.md "Runtime backend"; bin/fm-backend.sh, section 8); fm-pr-check, including through fm-pr-merge, records one canonical pr= and the forge's pr_head= when available (GitHub pull requests and GitLab merge requests; docs/gitlab-merge-watch.md); fm-x-link appends x_request=, x_request_ts=, x_followups=, and optional x_platform=/x_reply_max_chars= for an X-mode-originated task (section 14)
+  <id>.meta          written by fm-spawn: window=, endpoint_task_id=, worktree=, project=, harness=, model=, effort=, kind=, mode=, yolo=, tasktmp=; an optional traceparent= only when trace context is enabled (docs/configuration.md "Trace context propagation"); kind=secondmate also records home= and projects=, plus remote_host=/remote_root=/remote_backend=/remote_herdr_session=/remote_target= for a remote route; a non-default runtime backend records further backend-specific fields (docs/configuration.md "Runtime backend"; bin/fm-backend.sh, section 8); fm-pr-check, including through fm-pr-merge, records one canonical pr= and the forge's pr_head= when available (GitHub pull requests and GitLab merge requests; docs/gitlab-merge-watch.md); fm-x-link appends x_request=, x_request_ts=, x_followups=, and optional x_platform=/x_reply_max_chars= for an X-mode-originated task (section 14)
   <id>.herdr-presentation  quarantinable attempt and restart-binding journal for Herdr's optional visual projection; never task or endpoint authority; see docs/herdr-backend.md "Optional presentation spaces"
   <id>.check.sh      authenticated slow poll; the watcher dispatches validated PR data and the byte-identified X shim through trusted repository scripts, runs registered custom checks from hash-validated private snapshots, and rejects every other state check without execution
   <id>.check-trust   private content binding created by fm-check-register.sh for an intentional custom check

diff --git a/bin/fm-remote-doctor.sh b/bin/fm-remote-doctor.sh
@@ -9,10 +9,11 @@
 # recomposing it, so the entrypoint stays the single owner of that ordering and
 # the two can never drift.
 #
-# A remote second mate always runs on the Herdr backend, so readiness is more
-# than tool resolution. herdr must resolve, its server must be reachable, and on
-# macOS the Firstmate-owned launch agent dev.firstmate.herdr at
-# ~/Library/LaunchAgents/dev.firstmate.herdr.plist must exist, carry
+# A remote second mate always runs on the Herdr backend in the dedicated
+# fm-remote session, so readiness is more than tool resolution. herdr must
+# resolve, that server must be reachable, and on macOS the Firstmate-owned
+# launch agent dev.firstmate.herdr.fm-remote at
+# ~/Library/LaunchAgents/dev.firstmate.herdr.fm-remote.plist must exist, carry
 # LimitLoadToSessionType=Aqua, and be loaded into the console user's gui/<uid>
 # domain, so the server belongs to the GUI login session and survives logout and
 # SSH disconnection. SSH cannot create an Aqua session, so a host with no GUI
@@ -53,8 +54,11 @@ SCRIPT_DIR=${SCRIPT_SELF%/*}
 SCRIPT_DIR=$(CDPATH='' cd -- "$SCRIPT_DIR" && pwd -P)
 REQUIRED_TOOLS=(git jq)
 OPTIONAL_TOOLS=(tmux treehouse no-mistakes tasks-axi claude codex opencode pi grok kimi)
-LAUNCH_AGENT_LABEL=dev.firstmate.herdr
-HERDR_SESSION_NAME=default
+LAUNCH_AGENT_LABEL=dev.firstmate.herdr.fm-remote
+# The dedicated remote-secondmate session. The user's interactive Herdr work
+# remains in the separate default session, which this readiness check never
+# requires or changes.
+HERDR_SESSION_NAME=fm-remote
 LAUNCH_AGENT_DIR="${HOME:-}/Library/LaunchAgents"
 LAUNCH_AGENT_PLIST="$LAUNCH_AGENT_DIR/$LAUNCH_AGENT_LABEL.plist"
 LAUNCH_AGENT_LOG_DIR="${HOME:-}/Library/Logs"

diff --git a/bin/fm-remote-secondmate-control.sh b/bin/fm-remote-secondmate-control.sh
@@ -13,14 +13,19 @@
 #   fm-remote-secondmate-control.sh update <id>
 #   fm-remote-secondmate-control.sh retire <id> [--force]
 #
-# Remote placement ends here, but the second-mate agent itself always runs on
-# the Herdr backend, so launch refuses any other selection rather than reading
-# this home's config/backend; fm-spawn/fm-send/fm-teardown keep owning the local
-# endpoint mechanics, and the home's own workers keep its ordinary backend
-# selection. bin/fm-remote-doctor.sh owns that host's readiness for Herdr, and
-# docs/remote-secondmates.md owns why. A private parent-route state directory
-# stores only the remote secondmate agent's endpoint record; the home's own
+# Remote placement ends here, but the second-mate agent always runs on the
+# Herdr backend in the dedicated fm-remote session, so launch refuses any other
+# selection rather than reading this home's config/backend. The interactive
+# default session remains for the user's work.
+# fm-spawn/fm-send/fm-teardown keep owning the local endpoint mechanics.
+# The home's own workers keep their ordinary backend selection.
+# bin/fm-remote-doctor.sh owns that host's readiness for Herdr.
+# docs/remote-secondmates.md owns why.
+# A private parent-route state directory stores only the remote secondmate
+# agent's endpoint record; the home's own
 # state/*.meta remains reserved for workers the secondmate supervises.
+# Retirement closes only this secondmate's panes or workspace and never
+# stops fm-remote or removes a sibling secondmate's workspace or panes.
 #
 # The optional launch traceparent is the per-task W3C trace-context carrier the
 # PARENT home resolved for this secondmate; this host only delivers it to the
@@ -35,6 +40,7 @@ FM_ROOT="${FM_ROOT_OVERRIDE:-$(cd "$SCRIPT_DIR/.." && pwd)}"
 TARGET_HOME=${FM_HOME:?FM_HOME is required}
 CONTROL_STATE="$TARGET_HOME/state/parent-route"
 CONTROL_DATA="$TARGET_HOME/data/.parent-route"
+REMOTE_HERDR_SESSION=fm-remote
 
 # shellcheck source=bin/fm-backend.sh
 . "$SCRIPT_DIR/fm-backend.sh"
@@ -58,26 +64,59 @@ validate_home() { # <id> [allow-absent]
 
 meta_path() { printf '%s/%s.meta\n' "$CONTROL_STATE" "$1"; }
 
+remote_endpoint_load() {
+  local id=$1 herdr_session
+  REMOTE_ENDPOINT_ERROR=
+  REMOTE_ENDPOINT_META=$(meta_path "$id")
+  if ! fm_backend_validate_task_endpoint "$REMOTE_ENDPOINT_META" "$id" 2>/dev/null; then
+    REMOTE_ENDPOINT_ERROR="remote secondmate $id endpoint metadata is invalid; refusing access until it is explicitly migrated"
+    return 1
+  fi
+  REMOTE_ENDPOINT_BACKEND=$FM_BACKEND_VALIDATED_BACKEND
+  REMOTE_ENDPOINT_TARGET=$FM_BACKEND_VALIDATED_TARGET
+  if [ "$REMOTE_ENDPOINT_BACKEND" != herdr ]; then
+    REMOTE_ENDPOINT_ERROR="remote secondmate $id endpoint is recorded on backend '$REMOTE_ENDPOINT_BACKEND', expected 'herdr'; refusing access until it is explicitly migrated"
+    return 1
+  fi
+  herdr_session=$(fm_backend_meta_exact_value "$REMOTE_ENDPOINT_META" herdr_session 2>/dev/null || true)
+  if [ "$herdr_session" != "$REMOTE_HERDR_SESSION" ]; then
+    REMOTE_ENDPOINT_ERROR="remote secondmate $id endpoint is recorded in Herdr session '${herdr_session:-missing}', expected '$REMOTE_HERDR_SESSION'; refusing access until it is explicitly migrated"
+    return 1
+  fi
+  case "$REMOTE_ENDPOINT_TARGET" in
+    "$REMOTE_HERDR_SESSION":?*) ;;
+    *)
+      REMOTE_ENDPOINT_ERROR="remote secondmate $id endpoint target '$REMOTE_ENDPOINT_TARGET' is outside Herdr session '$REMOTE_HERDR_SESSION'; refusing access until it is explicitly migrated"
+      return 1
+      ;;
+  esac
+}
+
+remote_endpoint_require() {
+  remote_endpoint_load "$1" || die "$REMOTE_ENDPOINT_ERROR"
+}
+
 state_value() { # <id>; prints recovery-grade state
-  local id=$1 meta backend target
+  local id=$1 meta
   meta=$(meta_path "$id")
   [ -f "$meta" ] && [ ! -L "$meta" ] || { printf 'missing\n'; return 0; }
-  backend=$(fm_backend_of_meta "$meta")
-  target=$(fm_backend_target_of_meta "$meta")
-  [ -n "$target" ] || { printf 'unreadable\n'; return 0; }
-  fm_backend_agent_state "$backend" "$target" 2>/dev/null || printf 'unreadable\n'
+  if ! remote_endpoint_load "$id"; then
+    printf 'error: %s\n' "$REMOTE_ENDPOINT_ERROR" >&2
+    printf 'unverified\n'
+    return 0
+  fi
+  fm_backend_agent_state "$REMOTE_ENDPOINT_BACKEND" "$REMOTE_ENDPOINT_TARGET" 2>/dev/null || printf 'unreadable\n'
 }
 
 print_route() { # <id>
-  local meta=$1 backend target harness traceparent
-  meta=$(meta_path "$meta")
-  backend=$(fm_backend_of_meta "$meta")
-  target=$(fm_backend_target_of_meta "$meta")
-  harness=$(fm_meta_get "$meta" harness)
-  traceparent=$(fm_meta_get "$meta" traceparent)
+  local id=$1 harness traceparent
+  remote_endpoint_require "$id"
+  harness=$(fm_meta_get "$REMOTE_ENDPOINT_META" harness)
+  traceparent=$(fm_meta_get "$REMOTE_ENDPOINT_META" traceparent)
   printf 'schema=fm-remote-secondmate-control.v1\n'
-  printf 'backend=%s\n' "$backend"
-  printf 'target=%s\n' "$target"
+  printf 'backend=%s\n' "$REMOTE_ENDPOINT_BACKEND"
+  printf 'target=%s\n' "$REMOTE_ENDPOINT_TARGET"
+  printf 'herdr_session=%s\n' "$REMOTE_HERDR_SESSION"
   printf 'harness=%s\n' "$harness"
   [ -z "$traceparent" ] || printf 'traceparent=%s\n' "$traceparent"
 }
@@ -95,7 +134,7 @@ cmd_route() {
 
 cmd_launch() {
   local id=$1 harness=$2 model=$3 effort=$4 selected_backend=$5 traceparent=${6:-}
-  local current meta out backend target
+  local current meta out herdr_session
 
   validate_id "$id"
   validate_home "$id"
@@ -108,19 +147,16 @@ cmd_launch() {
   mkdir -p "$CONTROL_STATE" "$CONTROL_DATA"
   meta=$(meta_path "$id")
   if [ -f "$meta" ]; then
-    current=$(state_value "$id")
+    remote_endpoint_require "$id"
+    current=$(fm_backend_agent_state "$REMOTE_ENDPOINT_BACKEND" "$REMOTE_ENDPOINT_TARGET" 2>/dev/null || printf 'unreadable\n')
     case "$current" in
       alive)
-        backend=$(fm_backend_of_meta "$meta")
-        [ "$backend" = herdr ] \
-          || die "remote secondmate $id has an alive endpoint recorded on backend '$backend'; refusing reuse until it is explicitly migrated or retired"
         print_route "$id"
         return 0
         ;;
       dead)
-        backend=$(fm_backend_of_meta "$meta")
-        target=$(fm_backend_target_of_meta "$meta")
-        fm_backend_kill "$backend" "$target" 2>/dev/null || die "could not remove the confirmed agent-less endpoint"
+        fm_backend_kill "$REMOTE_ENDPOINT_BACKEND" "$REMOTE_ENDPOINT_TARGET" 2>/dev/null \
+          || die "could not remove the confirmed agent-less endpoint"
         ;;
       missing) ;;
       *) die "remote endpoint state is $current; refusing duplicate launch" ;;
@@ -130,65 +166,55 @@ cmd_launch() {
   [ "$model" = - ] || ARGS+=(--model "$model")
   [ "$effort" = - ] || ARGS+=(--effort "$effort")
   [ -z "$traceparent" ] || ARGS+=(--traceparent "$traceparent")
-  if ! out=$(FM_HOME="$FM_ROOT" FM_ROOT_OVERRIDE="$FM_ROOT" \
+  if ! out=$(HERDR_SESSION="$REMOTE_HERDR_SESSION" FM_HOME="$FM_ROOT" FM_ROOT_OVERRIDE="$FM_ROOT" \
     FM_STATE_OVERRIDE="$CONTROL_STATE" FM_DATA_OVERRIDE="$CONTROL_DATA" \
     FM_CONFIG_OVERRIDE="$TARGET_HOME/config" FM_SKIP_SECONDMATE_INHERIT=1 \
     "$SCRIPT_DIR/fm-spawn.sh" "${ARGS[@]}" 2>&1); then
     [ -z "$out" ] || printf '%s\n' "$out" >&2
     die "remote host-local secondmate launch failed"
   fi
   [ -f "$meta" ] || die "remote launch returned without endpoint metadata"
+  herdr_session=$(fm_meta_get "$meta" herdr_session)
+  [ "$herdr_session" = "$REMOTE_HERDR_SESSION" ] \
+    || die "remote launch recorded Herdr session '${herdr_session:-missing}', expected '$REMOTE_HERDR_SESSION'"
   print_route "$id"
 }
 
 cmd_send() {
-  local id=$1 message=$2 meta backend target
+  local id=$1 message=$2
   validate_id "$id"
   validate_home "$id"
-  meta=$(meta_path "$id")
-  [ -f "$meta" ] || die "remote secondmate has no endpoint metadata"
-  backend=$(fm_backend_of_meta "$meta")
-  target=$(fm_backend_target_of_meta "$meta")
-  [ -n "$target" ] || die "remote secondmate endpoint is unreadable"
+  remote_endpoint_require "$id"
   FM_HOME="$TARGET_HOME" FM_ROOT_OVERRIDE="$FM_ROOT" FM_STATE_OVERRIDE="$TARGET_HOME/state" \
-    "$SCRIPT_DIR/fm-send.sh" "$target" "$message"
+    "$SCRIPT_DIR/fm-send.sh" "$REMOTE_ENDPOINT_TARGET" "$message"
 }
 
 cmd_key() {
-  local id=$1 key=$2 meta target
+  local id=$1 key=$2
   validate_id "$id"
   validate_home "$id"
-  meta=$(meta_path "$id")
-  [ -f "$meta" ] || die "remote secondmate has no endpoint metadata"
-  target=$(fm_backend_target_of_meta "$meta")
+  remote_endpoint_require "$id"
   FM_HOME="$TARGET_HOME" FM_ROOT_OVERRIDE="$FM_ROOT" FM_STATE_OVERRIDE="$TARGET_HOME/state" \
-    "$SCRIPT_DIR/fm-send.sh" "$target" --key "$key"
+    "$SCRIPT_DIR/fm-send.sh" "$REMOTE_ENDPOINT_TARGET" --key "$key"
 }
 
 cmd_capture() {
-  local id=$1 lines=${2:-20} meta backend target
+  local id=$1 lines=${2:-20}
   validate_id "$id"
   validate_home "$id"
   case "$lines" in ''|*[!0-9]*|0) die "capture line count must be positive" ;; esac
   [ "$lines" -le 100 ] || die "capture line count exceeds 100"
-  meta=$(meta_path "$id")
-  [ -f "$meta" ] || die "remote secondmate has no endpoint metadata"
-  backend=$(fm_backend_of_meta "$meta")
-  target=$(fm_backend_target_of_meta "$meta")
-  fm_backend_capture "$backend" "$target" "$lines" "fm-$id" | head -c 65536
+  remote_endpoint_require "$id"
+  fm_backend_capture "$REMOTE_ENDPOINT_BACKEND" "$REMOTE_ENDPOINT_TARGET" "$lines" "fm-$id" | head -c 65536
 }
 
 cmd_observe() {
-  local id=$1 meta backend target harness
+  local id=$1 harness
   validate_id "$id"
   validate_home "$id"
-  meta=$(meta_path "$id")
-  [ -f "$meta" ] || die "remote secondmate has no endpoint metadata"
-  backend=$(fm_backend_of_meta "$meta")
-  target=$(fm_backend_target_of_meta "$meta")
-  harness=$(fm_meta_get "$meta" harness)
-  [ -n "$target" ] || die "remote secondmate endpoint is unreadable"
-  fm_pending_reply_backend_observation "$backend" "$target" "fm-$id" "$harness"
+  remote_endpoint_require "$id"
+  harness=$(fm_meta_get "$REMOTE_ENDPOINT_META" harness)
+  fm_pending_reply_backend_observation "$REMOTE_ENDPOINT_BACKEND" "$REMOTE_ENDPOINT_TARGET" "fm-$id" "$harness"
   printf '\n'
 }
 
@@ -244,7 +270,7 @@ cmd_retire() {
     return 0
   fi
   [ -z "$force" ] || [ "$force" = --force ] || usage
-  [ -f "$(meta_path "$id")" ] || die "remote secondmate has no endpoint metadata to retire safely"
+  remote_endpoint_require "$id"
   FM_HOME="$TARGET_HOME" FM_ROOT_OVERRIDE="$FM_ROOT" FM_STATE_OVERRIDE="$TARGET_HOME/state" \
     FM_CONFIG_OVERRIDE="$TARGET_HOME/config" "$SCRIPT_DIR/fm-guard.sh" || true
   if [ -n "$force" ]; then

diff --git a/bin/fm-send.sh b/bin/fm-send.sh
@@ -165,6 +165,11 @@ fm_send_resolve_target() {  # <raw-target>
   fi
 
   case "$raw" in
+    fm-*:*)
+      # A named Herdr session may itself begin with "fm-". Keep that explicit
+      # session:pane target on the validated backend-target path below rather
+      # than mistaking it for an unresolved task selector.
+      ;;
     fm-*)
       RESOLUTION_TRIED="meta=$STATE/$raw.meta; legacy-meta=$STATE/${raw#fm-}.meta; backend=none"
       echo "error: no metadata for $raw in $STATE (tried $RESOLUTION_TRIED); pass a well-formed explicit backend target only when targeting outside this firstmate home" >&2

diff --git a/bin/fm-spawn.sh b/bin/fm-spawn.sh
@@ -335,7 +335,7 @@ fi
 
 spawn_remote_secondmate() {
   local id=$1 remote host root home harness positional model effort backend out rc meta tmp
-  local remote_backend remote_target remote_harness registry_lock remote_lock remote_generation
+  local remote_backend remote_target remote_harness remote_herdr_session registry_lock remote_lock remote_generation
   local remote_traceparent remote_recorded_traceparent
   local -a launch_args
   id=${POS[0]:-}
@@ -513,6 +513,7 @@ spawn_remote_secondmate() {
   remote_backend=$(printf '%s\n' "$out" | sed -n 's/^backend=//p' | tail -1)
   remote_target=$(printf '%s\n' "$out" | sed -n 's/^target=//p' | tail -1)
   remote_harness=$(printf '%s\n' "$out" | sed -n 's/^harness=//p' | tail -1)
+  remote_herdr_session=$(printf '%s\n' "$out" | sed -n 's/^herdr_session=//p' | tail -1)
   if [ "$remote_backend" != herdr ]; then
     fm_lock_release "$remote_lock" || true
     fm_lock_release "$registry_lock" || true
@@ -527,6 +528,13 @@ spawn_remote_secondmate() {
     echo "error: remote launch returned malformed route metadata; preserving the remote route for reconciliation" >&2
     return 1
   }
+  if [ "$remote_herdr_session" != fm-remote ] || [ "${remote_target%%:*}" != "$remote_herdr_session" ]; then
+    fm_lock_release "$remote_lock" || true
+    fm_lock_release "$registry_lock" || true
+    fm_lock_release "$SPAWN_TASK_LOCK" || true
+    echo "error: remote launch returned Herdr session '${remote_herdr_session:-missing}', expected 'fm-remote'; preserving the remote route for reconciliation" >&2
+    return 1
+  fi
   # Record what the remote endpoint ACTUALLY carries, read back from its own
   # launch, rather than what this side hoped to deliver. That keeps the #995
   # guarantee that the recorded carrier is the identity the child received even
@@ -553,6 +561,7 @@ spawn_remote_secondmate() {
     echo "remote_host=$host"
     echo "remote_root=$root"
     echo "remote_backend=$remote_backend"
+    echo "remote_herdr_session=$remote_herdr_session"
     echo "remote_target=$remote_target"
     [ -z "$remote_recorded_traceparent" ] || echo "traceparent=$remote_recorded_traceparent"
   } > "$tmp"