feat(fleet): add durable tmux fleet poc

2026-06-19 15:23:14 -05:00
parent 250d3da12d
commit 757f5e6998
11 changed files with 313 additions and 31 deletions
--- a/packages/mosaic/framework/systemd/user/README.md
+++ b/packages/mosaic/framework/systemd/user/README.md
@@ -0,0 +1,57 @@
+# Mosaic tmux Fleet PoC
+
+This directory contains the first durable tmux-backed fleet primitives for the
+Mosaic software-factory model.
+
+The lifecycle model follows the organization-neutral AI Guide playbook
+`mosaicstack/aiguide:playbooks/tmux-fleet.md` (commit `2a0b0b5`): a dedicated
+holder owns the tmux server/socket; agent units join it and stop only their own
+exact-match session.
+
+## Layout
+
+- `mosaic-tmux-holder.service` — user-mode holder that owns the named tmux server.
+- `mosaic-agent@.service` — user-mode template for one reusable agent session.
+- `test-fleet-units.sh` — validates unit syntax and required relationships.
+
+The agent template calls:
+
+```text
+~/.config/mosaic/tools/fleet/start-agent-session.sh <agent-name>
+```
+
+which starts or reuses a tmux session on `MOSAIC_TMUX_SOCKET`.
+
+## Local customization
+
+Per-agent overrides live outside the package in:
+
+```text
+~/.config/mosaic/fleet/agents/<agent>.env
+```
+
+Example:
+
+```dotenv
+MOSAIC_TMUX_SOCKET=mosaic-factory
+MOSAIC_AGENT_RUNTIME=claude
+MOSAIC_AGENT_WORKDIR=/home/jarvis/src/mosaic-stack
+# Optional escape hatch for PoC/canary agents:
+# MOSAIC_AGENT_COMMAND=mosaic yolo claude
+```
+
+## Manual canary sequence
+
+```bash
+mkdir -p ~/.config/systemd/user ~/.config/mosaic/tools/fleet ~/.config/mosaic/fleet/agents
+cp packages/mosaic/framework/systemd/user/mosaic-*.service ~/.config/systemd/user/
+cp packages/mosaic/framework/tools/fleet/start-agent-session.sh ~/.config/mosaic/tools/fleet/
+chmod +x ~/.config/mosaic/tools/fleet/start-agent-session.sh
+systemctl --user daemon-reload
+systemctl --user start mosaic-tmux-holder.service
+systemctl --user start mosaic-agent@canary.service
+tmux -L mosaic-factory ls
+```
+
+Do not use `tmux kill-server` without `-L mosaic-factory`; this pattern is meant
+to avoid disturbing the user's default tmux server.
--- a/packages/mosaic/framework/systemd/user/mosaic-agent@.service
+++ b/packages/mosaic/framework/systemd/user/mosaic-agent@.service
@@ -0,0 +1,20 @@
+[Unit]
+Description=Mosaic tmux fleet agent %i
+Documentation=https://git.mosaicstack.dev/mosaicstack/stack
+Requires=mosaic-tmux-holder.service
+After=mosaic-tmux-holder.service
+PartOf=mosaic-tmux-holder.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+Environment=MOSAIC_TMUX_SOCKET=mosaic-factory
+Environment=MOSAIC_AGENT_NAME=%i
+Environment=MOSAIC_AGENT_RUNTIME=pi
+Environment=MOSAIC_AGENT_WORKDIR=%h
+EnvironmentFile=-%h/.config/mosaic/fleet/agents/%i.env
+ExecStart=/bin/bash %h/.config/mosaic/tools/fleet/start-agent-session.sh %i
+ExecStop=-/bin/bash -lc 'tmux -L "${MOSAIC_TMUX_SOCKET:-mosaic-factory}" kill-session -t "=%i"'
+
+[Install]
+WantedBy=default.target
--- a/packages/mosaic/framework/systemd/user/mosaic-tmux-holder.service
+++ b/packages/mosaic/framework/systemd/user/mosaic-tmux-holder.service
@@ -0,0 +1,15 @@
+[Unit]
+Description=Mosaic tmux fleet holder
+Documentation=https://git.mosaicstack.dev/mosaicstack/stack
+After=default.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+Environment=MOSAIC_TMUX_SOCKET=mosaic-factory
+Environment=MOSAIC_TMUX_HOLDER=_holder
+ExecStart=/bin/bash -lc 'tmux -L "$MOSAIC_TMUX_SOCKET" has-session -t "=${MOSAIC_TMUX_HOLDER}:0.0" 2>/dev/null || tmux -L "$MOSAIC_TMUX_SOCKET" new-session -d -s "$MOSAIC_TMUX_HOLDER" "while true; do sleep 3600; done"'
+ExecStop=-/bin/bash -lc 'tmux -L "$MOSAIC_TMUX_SOCKET" kill-server'
+
+[Install]
+WantedBy=default.target
--- a/packages/mosaic/framework/systemd/user/test-fleet-units.sh
+++ b/packages/mosaic/framework/systemd/user/test-fleet-units.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR=$(cd -- "$(dirname -- "$0")" && pwd)
+HOLDER="$SCRIPT_DIR/mosaic-tmux-holder.service"
+AGENT="$SCRIPT_DIR/mosaic-agent@.service"
+
+fail() {
+  echo "FAIL: $*" >&2
+  exit 1
+}
+
+[ -f "$HOLDER" ] || fail "missing mosaic-tmux-holder.service"
+[ -f "$AGENT" ] || fail "missing mosaic-agent@.service"
+
+grep -qF 'ExecStart=' "$HOLDER" || fail "holder has no ExecStart"
+grep -qF 'tmux -L' "$HOLDER" || fail "holder does not use named tmux socket"
+grep -qF '_holder' "$HOLDER" || fail "holder session is not explicit"
+grep -qF 'Requires=mosaic-tmux-holder.service' "$AGENT" || fail "agent does not require holder"
+grep -qF 'start-agent-session.sh' "$AGENT" || fail "agent unit does not call start-agent-session.sh"
+grep -qF 'kill-session -t "=%i"' "$AGENT" || fail "agent stop does not exact-match its session"
+
+if command -v systemd-analyze >/dev/null 2>&1; then
+  systemd-analyze verify --user "$HOLDER" "$AGENT" >/tmp/mosaic-fleet-systemd-verify.log 2>&1 || {
+    cat /tmp/mosaic-fleet-systemd-verify.log >&2
+    fail "systemd-analyze verify failed"
+  }
+fi
+
+echo "ok - fleet systemd unit templates"
--- a/packages/mosaic/framework/tools/fleet/start-agent-session.sh
+++ b/packages/mosaic/framework/tools/fleet/start-agent-session.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+AGENT_NAME=${1:-${MOSAIC_AGENT_NAME:-}}
+MOSAIC_TMUX_SOCKET=${MOSAIC_TMUX_SOCKET:-mosaic-factory}
+MOSAIC_AGENT_RUNTIME=${MOSAIC_AGENT_RUNTIME:-pi}
+MOSAIC_AGENT_WORKDIR=${MOSAIC_AGENT_WORKDIR:-$HOME}
+MOSAIC_AGENT_COMMAND=${MOSAIC_AGENT_COMMAND:-}
+
+if [ -z "$AGENT_NAME" ]; then
+  echo "ERROR: agent name argument or MOSAIC_AGENT_NAME is required" >&2
+  exit 64
+fi
+
+if ! command -v tmux >/dev/null 2>&1; then
+  echo "ERROR: tmux is required" >&2
+  exit 69
+fi
+
+if tmux -L "$MOSAIC_TMUX_SOCKET" has-session -t "=${AGENT_NAME}:0.0" 2>/dev/null; then
+  echo "Mosaic agent session already running: $AGENT_NAME on socket $MOSAIC_TMUX_SOCKET"
+  exit 0
+fi
+
+if [ -z "$MOSAIC_AGENT_COMMAND" ]; then
+  MOSAIC_AGENT_COMMAND="mosaic yolo $MOSAIC_AGENT_RUNTIME"
+fi
+
+mkdir -p "$MOSAIC_AGENT_WORKDIR"
+exec tmux -L "$MOSAIC_TMUX_SOCKET" new-session -d -s "$AGENT_NAME" -c "$MOSAIC_AGENT_WORKDIR" "$MOSAIC_AGENT_COMMAND"
--- a/packages/mosaic/framework/tools/fleet/test-start-agent-session.sh
+++ b/packages/mosaic/framework/tools/fleet/test-start-agent-session.sh
@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR=$(cd -- "$(dirname -- "$0")" && pwd)
+START="$SCRIPT_DIR/start-agent-session.sh"
+SOCKET="mosaic-agent-test-$RANDOM-$$"
+AGENT="agent-$RANDOM"
+WORKDIR=$(mktemp -d)
+trap 'tmux -L "$SOCKET" kill-server >/dev/null 2>&1 || true; rm -rf "$WORKDIR"' EXIT
+
+fail() {
+  echo "FAIL: $*" >&2
+  exit 1
+}
+
+MOSAIC_TMUX_SOCKET="$SOCKET" \
+MOSAIC_AGENT_WORKDIR="$WORKDIR" \
+MOSAIC_AGENT_COMMAND='bash --noprofile --norc -i' \
+  "$START" "$AGENT"
+
+tmux -L "$SOCKET" has-session -t "=$AGENT:0.0" || fail "agent session was not created"
+actual_dir=$(tmux -L "$SOCKET" display-message -p -t "=$AGENT:0.0" '#{pane_current_path}')
+[ "$actual_dir" = "$WORKDIR" ] || fail "agent workdir mismatch: $actual_dir"
+
+MOSAIC_TMUX_SOCKET="$SOCKET" \
+MOSAIC_AGENT_WORKDIR="$WORKDIR" \
+MOSAIC_AGENT_COMMAND='bash --noprofile --norc -i' \
+  "$START" "$AGENT" >/tmp/mosaic-start-agent-idempotent.out
+
+grep -qF 'already running' /tmp/mosaic-start-agent-idempotent.out || fail "duplicate start was not idempotent"
+
+echo "ok - start-agent-session"
--- a/packages/mosaic/framework/tools/tmux/README.md
+++ b/packages/mosaic/framework/tools/tmux/README.md
@@ -31,9 +31,12 @@ Prepends the preamble automatically (auto-detecting your own `host:session`) and
 delivers reliably to local OR remote panes.

 ```bash
-# Local target (same host)
+# Local target (same host, default tmux server)
 agent-send.sh -s <dst_session> -m "message"

+# Local target on a Mosaic fleet socket
+agent-send.sh -L mosaic-factory -s '=coder0' -m "message"
+
 # Remote target (over ssh)
 agent-send.sh -H user@host -s <dst_session> -m "message"

@@ -42,10 +45,27 @@ agent-send.sh -H user@host -s <dst_session> -f msg.txt
 echo "msg" | agent-send.sh -s <dst_session>
 ```

-Key flags: `-s` dst session (required) · `-H` ssh target for remote · `-n` dst
+Key flags: `-L` named tmux socket · `-s` dst session (required) · `-H` ssh target for remote · `-n` dst
 hostname for the preamble (else auto-resolved) · `-m`/`-f`/stdin body · `-S`
 override source label · `-v` verbose · `-r N` Enter-flush attempts.

+For durable fleet use, prefer exact tmux targets such as `=coder0`. The helper
+normalizes exact session targets to pane-qualified targets internally so pane
+commands do not fall back to tmux's prefix matching behavior.
+
+## Named socket isolation
+
+Durable Mosaic fleets should use a dedicated tmux socket, for example:
+
+```bash
+tmux -L mosaic-factory ls
+agent-send.sh -L mosaic-factory -s '=coder0' -m "status?"
+send-message.sh -L mosaic-factory -t '=coder0' -m "raw pane message"
+```
+
+This keeps fleet operations away from the user's default tmux server. It is the
+safe rollout path on hosts that already have manual tmux sessions.
+
 ## Why a helper exists (the submission gotcha)

 Pasting into an interactive REPL via raw `tmux send-keys` is unreliable: a
@@ -67,6 +87,7 @@ message crosses the wire as base64 (`-b`) to avoid all shell-quoting hazards.

 - `agent-send.sh` — inter-agent wrapper (preamble + local/remote dispatch).
 - `send-message.sh` — low-level reliable single-pane submitter (`-b` base64 input).
+- `test-send-message-socket.sh` — smoke test for named-socket isolation.

 ## Distribution

--- a/packages/mosaic/framework/tools/tmux/agent-send.sh
+++ b/packages/mosaic/framework/tools/tmux/agent-send.sh
@@ -23,12 +23,13 @@
 #   the remote host; only bash + tmux + base64 (standard).
 #
 # USAGE
-#   agent-send.sh -s <dst_session> -m "message"                 # local target
-#   agent-send.sh -H user@host -s <dst_session> -m "message"    # remote target
-#   agent-send.sh -H user@host -n <dst_hostname> -s <sess> -f msg.txt
-#   echo "msg" | agent-send.sh -H user@host -s <dst_session>
+#   agent-send.sh [-L socket] -s <dst_session> -m "message"                 # local target
+#   agent-send.sh [-L socket] -H user@host -s <dst_session> -m "message"    # remote target
+#   agent-send.sh [-L socket] -H user@host -n <dst_hostname> -s <sess> -f msg.txt
+#   echo "msg" | agent-send.sh [-L socket] -H user@host -s <dst_session>
 #
 # OPTIONS
+#   -L NAME         tmux socket name passed to `tmux -L NAME` on the target host
 #   -s DST_SESSION  target tmux session (or session:window.pane)   [required]
 #   -H SSH_TARGET   ssh target (user@host) for a remote pane; omit for local
 #   -n DST_HOST     hostname to show in the preamble for the target.
@@ -47,12 +48,13 @@ set -uo pipefail
 SELF_DIR=$(cd -- "$(dirname -- "$0")" && pwd)
 SENDER="$SELF_DIR/send-message.sh"

-DST_SESSION=""; SSH_TARGET=""; DST_HOST=""; MSG=""; FILE=""
+DST_SESSION=""; SSH_TARGET=""; DST_HOST=""; MSG=""; FILE=""; SOCKET_NAME=""
 SRC_LABEL=""; RETRIES=2; VERBOSE=0
 usage() { sed -n '2,44p' "$0"; exit "${1:-3}"; }

-while getopts "s:H:n:m:f:S:r:vh" o; do
+while getopts "L:s:H:n:m:f:S:r:vh" o; do
  case "$o" in
+    L) SOCKET_NAME=$OPTARG ;;
    s) DST_SESSION=$OPTARG ;; H) SSH_TARGET=$OPTARG ;; n) DST_HOST=$OPTARG ;;
    m) MSG=$OPTARG ;; f) FILE=$OPTARG ;; S) SRC_LABEL=$OPTARG ;;
    r) RETRIES=$OPTARG ;; v) VERBOSE=1 ;; h) usage 0 ;; *) usage 3 ;;
@@ -70,8 +72,12 @@ fi

 # Source label: this agent's host:session (auto-detected, overridable).
 if [ -z "$SRC_LABEL" ]; then
+  tmux_cmd=(tmux)
+  if [ -n "$SOCKET_NAME" ]; then
+    tmux_cmd+=(-L "$SOCKET_NAME")
+  fi
  src_host=$(hostname -s 2>/dev/null || echo "?")
-  src_sess=$(tmux display-message -p '#S' 2>/dev/null || echo "?")
+  src_sess=$("${tmux_cmd[@]}" display-message -p '#S' 2>/dev/null || echo "?")
  SRC_LABEL="${src_host}:${src_sess}"
 fi

@@ -89,12 +95,16 @@ FULL="${PREAMBLE} ${MSG}"
 B64=$(printf '%s' "$FULL" | base64 -w0)

 vflag=""; [ "$VERBOSE" = 1 ] && vflag="-v"
+socket_args=()
+if [ -n "$SOCKET_NAME" ]; then
+  socket_args=(-L "$SOCKET_NAME")
+fi

 if [ -z "$SSH_TARGET" ]; then
  # Local pane: call the canonical sender directly.
-  exec "$SENDER" -t "$DST_SESSION" -b "$B64" -r "$RETRIES" $vflag
+  exec "$SENDER" "${socket_args[@]}" -t "$DST_SESSION" -b "$B64" -r "$RETRIES" $vflag
 else
  # Remote pane: ship the sender over ssh and run it local to the target.
  ssh -o ConnectTimeout=10 "$SSH_TARGET" \
-      "bash -s -- -t '$DST_SESSION' -b '$B64' -r '$RETRIES' $vflag" < "$SENDER"
+      "bash -s -- ${socket_args[*]@Q} -t '$DST_SESSION' -b '$B64' -r '$RETRIES' $vflag" < "$SENDER"
 fi
--- a/packages/mosaic/framework/tools/tmux/send-message.sh
+++ b/packages/mosaic/framework/tools/tmux/send-message.sh
@@ -13,12 +13,13 @@
 #   no-op in Claude Code, so the double-Enter is safe.
 #
 # USAGE
-#   send-message.sh -t <target> -m "message"
-#   send-message.sh -t <target> -f <file>
-#   echo "message" | send-message.sh -t <target>
-#   ssh host bash -s -- -t <target> -b "$(base64 -w0 <<<msg)" < send-message.sh
+#   send-message.sh [-L socket_name] -t <target> -m "message"
+#   send-message.sh [-L socket_name] -t <target> -f <file>
+#   echo "message" | send-message.sh [-L socket_name] -t <target>
+#   ssh host bash -s -- -L socket -t <target> -b "$(base64 -w0 <<<msg)" < send-message.sh
 #
 # OPTIONS
+#   -L NAME     tmux socket name passed to `tmux -L NAME` (optional)
 #   -t TARGET   tmux target: session, or session:window.pane  [required]
 #   -m MESSAGE  message text (single- or multi-line)
 #   -f FILE     read message from FILE instead of -m
@@ -34,11 +35,12 @@
 #   3  usage error
 set -uo pipefail

-TARGET=""; MSG=""; FILE=""; B64=""; RETRIES=2; VERBOSE=0
+SOCKET_NAME=""; TARGET=""; MSG=""; FILE=""; B64=""; RETRIES=2; VERBOSE=0
 usage() { sed -n '2,34p' "$0"; exit "${1:-3}"; }

-while getopts "t:m:f:b:r:vh" o; do
+while getopts "L:t:m:f:b:r:vh" o; do
  case "$o" in
+    L) SOCKET_NAME=$OPTARG ;;
    t) TARGET=$OPTARG ;; m) MSG=$OPTARG ;; f) FILE=$OPTARG ;; b) B64=$OPTARG ;;
    r) RETRIES=$OPTARG ;; v) VERBOSE=1 ;; h) usage 0 ;; *) usage 3 ;;
  esac
@@ -51,8 +53,21 @@ elif [ -z "$MSG" ] && [ ! -t 0 ]; then MSG=$(cat)
 fi
 [ -n "$MSG" ] || { echo "ERROR: empty message (use -m, -f, or stdin)" >&2; exit 3; }

+tmux_cmd=(tmux)
+if [ -n "$SOCKET_NAME" ]; then
+  tmux_cmd+=(-L "$SOCKET_NAME")
+fi
+
+# tmux accepts `=session` for some commands, but pane-level commands such as
+# capture-pane require a pane-qualified target. Keep exact-session addressing
+# convenient while avoiding accidental prefix matches.
+EFFECTIVE_TARGET=$TARGET
+if [[ "$TARGET" == =* && "$TARGET" != *:* ]]; then
+  EFFECTIVE_TARGET="${TARGET}:0.0"
+fi
+
 # Target must resolve to a live pane.
-if ! tmux list-panes -t "$TARGET" >/dev/null 2>&1; then
+if ! "${tmux_cmd[@]}" list-panes -t "$EFFECTIVE_TARGET" >/dev/null 2>&1; then
  echo "ERROR: tmux target not found: $TARGET" >&2; exit 1
 fi

@@ -62,18 +77,18 @@ snippet=$(printf '%s' "$MSG" | tr '\n' ' ' | tr -s ' ' | sed 's/[^[:print:]]//g'

 # 1) Paste the body as a bracketed paste so multi-line content does not submit
 #    line-by-line. load-buffer/paste-buffer is far safer than `send-keys -l`.
-printf '%s' "$MSG" | tmux load-buffer -b __mosaic_send -
+printf '%s' "$MSG" | "${tmux_cmd[@]}" load-buffer -b __mosaic_send -
 # -p = bracketed paste when the client supports it; fall back if not.
-tmux paste-buffer -d -p -b __mosaic_send -t "$TARGET" 2>/dev/null \
-  || tmux paste-buffer -d -b __mosaic_send -t "$TARGET"
+"${tmux_cmd[@]}" paste-buffer -d -p -b __mosaic_send -t "$EFFECTIVE_TARGET" 2>/dev/null \
+  || "${tmux_cmd[@]}" paste-buffer -d -b __mosaic_send -t "$EFFECTIVE_TARGET"
 sleep 0.5

 # 2) Submit, then verify; flush with another Enter if it is still a draft.
 status="sent"
 for attempt in $(seq 1 $((RETRIES + 1))); do
-  tmux send-keys -t "$TARGET" Enter
+  "${tmux_cmd[@]}" send-keys -t "$EFFECTIVE_TARGET" Enter
  sleep 1.2
-  pane=$(tmux capture-pane -t "$TARGET" -p 2>/dev/null)
+  pane=$("${tmux_cmd[@]}" capture-pane -t "$EFFECTIVE_TARGET" -p 2>/dev/null)

  if printf '%s' "$pane" | grep -qF "$QUEUED_RE"; then
    status="queued"; break
--- a/packages/mosaic/framework/tools/tmux/test-send-message-socket.sh
+++ b/packages/mosaic/framework/tools/tmux/test-send-message-socket.sh
@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR=$(cd -- "$(dirname -- "$0")" && pwd)
+SEND_MESSAGE="$SCRIPT_DIR/send-message.sh"
+AGENT_SEND="$SCRIPT_DIR/agent-send.sh"
+SOCKET="mosaic-test-$RANDOM-$$"
+TARGET="target-$RANDOM"
+DEFAULT_TARGET="default-target-$RANDOM"
+TMPDIR=$(mktemp -d)
+trap 'tmux -L "$SOCKET" kill-server >/dev/null 2>&1 || true; tmux kill-session -t "$DEFAULT_TARGET" >/dev/null 2>&1 || true; rm -rf "$TMPDIR"' EXIT
+
+fail() {
+  echo "FAIL: $*" >&2
+  exit 1
+}
+
+require_tmux() {
+  command -v tmux >/dev/null 2>&1 || fail "tmux is required"
+}
+
+capture_named() {
+  tmux -L "$SOCKET" capture-pane -t "=$TARGET:0.0" -p
+}
+
+capture_default() {
+  tmux capture-pane -t "=$DEFAULT_TARGET:0.0" -p
+}
+
+require_tmux
+
+tmux -L "$SOCKET" new-session -d -s "$TARGET" -c "$TMPDIR" 'bash --noprofile --norc -i'
+tmux new-session -d -s "$DEFAULT_TARGET" -c "$TMPDIR" 'bash --noprofile --norc -i'
+
+"$SEND_MESSAGE" -L "$SOCKET" -t "=$TARGET" -m "named socket hello" >/tmp/send-message-named.out
+sleep 0.2
+capture_named | grep -qF "named socket hello" || fail "send-message.sh did not deliver to named socket"
+if capture_default | grep -qF "named socket hello"; then
+  fail "send-message.sh leaked named-socket message to default tmux server"
+fi
+
+"$AGENT_SEND" -L "$SOCKET" -S "tester:source" -s "=$TARGET" -m "agent socket hello" >/tmp/agent-send-named.out
+sleep 0.2
+capture_named | grep -qF "[tester:source ->" || fail "agent-send.sh did not include preamble"
+capture_named | grep -qF "agent socket hello" || fail "agent-send.sh did not deliver to named socket"
+if capture_default | grep -qF "agent socket hello"; then
+  fail "agent-send.sh leaked named-socket message to default tmux server"
+fi
+
+echo "ok - named tmux socket send tools"
--- a/scratchpads/2026-06-19-tmux-fleet-durable-install-plan.md
+++ b/scratchpads/2026-06-19-tmux-fleet-durable-install-plan.md
@@ -6,6 +6,8 @@

 **Architecture:** Mosaic should ship generic tmux fleet primitives in the framework, then layer local rosters through configuration. The holder service owns the tmux socket; each agent service joins the holder-owned server and runs `mosaic yolo <runtime>`. The orchestrator addresses agents through `mosaic agent ...` abstractions so tmux can later be replaced by Matrix-backed agent comms without changing mission flow.

+**Reference:** AI Guide `playbooks/tmux-fleet.md` at commit `2a0b0b5` documents the organization-neutral holder-service pattern, exact-match `=<name>` stop targets, and coupled-server cutover/verification sequence. The Stack implementation should treat that as the lifecycle model and keep concrete Mosaic unit/tooling details here.
+
 **Tech Stack:** Bash, tmux, user systemd units, Mosaic CLI/framework installer, JSON/YAML roster config, existing `packages/mosaic/framework/tools/tmux/{agent-send.sh,send-message.sh}`.

 ---
@@ -714,14 +716,14 @@ The implementation is complete when:

 ## Risks and mitigations

-| Risk | Mitigation |
-|---|---|
-| Killing existing tmux sessions | Use named `mosaic-factory` socket; no default `tmux kill-server`. |
-| systemd unit quoting/env expansion bugs | Move logic into shell wrappers; verify with `systemd-analyze --user verify`. |
-| Runtime reset command mismatch | Make reset command runtime-configurable; fallback to service restart + kickstart. |
-| Tool install drift | Ensure npm package includes framework tmux/fleet tools; add packaging test. |
-| Mosaic-specific assumptions leak into generic guide | Keep USC roster as example profile; AI Guide documents pattern/options. |
-| Matrix migration blocked by tmux coupling | Add `mosaic agent` abstraction now; keep tmux details below transport layer. |
+| Risk                                                | Mitigation                                                                        |
+| --------------------------------------------------- | --------------------------------------------------------------------------------- |
+| Killing existing tmux sessions                      | Use named `mosaic-factory` socket; no default `tmux kill-server`.                 |
+| systemd unit quoting/env expansion bugs             | Move logic into shell wrappers; verify with `systemd-analyze --user verify`.      |
+| Runtime reset command mismatch                      | Make reset command runtime-configurable; fallback to service restart + kickstart. |
+| Tool install drift                                  | Ensure npm package includes framework tmux/fleet tools; add packaging test.       |
+| Mosaic-specific assumptions leak into generic guide | Keep USC roster as example profile; AI Guide documents pattern/options.           |
+| Matrix migration blocked by tmux coupling           | Add `mosaic agent` abstraction now; keep tmux details below transport layer.      |

 ## Suggested first PR split