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stack/packages/mosaic/framework/systemd/user
Jason Woltje fa2abd462d
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fix(fleet): consume model_hint + fix socket-default trap (#626)
Two spawn-side blockers found building the live PoC roster.

FIX 1 — model_hint not consumed: start-agent-session.sh built 'mosaic yolo
$RUNTIME' with no --model, so pi workers ignored the roster's model. Now
generateAgentEnv emits MOSAIC_AGENT_MODEL=<hint> and the launcher appends
${MOSAIC_AGENT_MODEL:+--model $MOSAIC_AGENT_MODEL} → workers run on e.g.
openai-codex/gpt-5.5:high.

FIX 2 — socket default trap: an ABSENT roster socket silently became
mosaic-factory in THREE places (parseRosterText fallback; the
mosaic-agent@.service Environment= default + ExecStop :-mosaic-factory;
start-agent-session :-mosaic-factory). The live PoC runs on the DEFAULT tmux
socket (socket_name absent). Now absent ⇒ '' ⇒ the literal default socket (no
-L) consistently across spawn, the systemd unit, fleet ps/watch observe, and
the onboarding cheat-sheet:
- socketArgs(name) → name ? ['-L', name] : []; replaces all ~15 -L sites in
  fleet.ts. parseRosterText fallback '' (was DEFAULT_SOCKET_NAME).
- shellEnvValue('') now emits a BARE 'VAR=' (not ''), so a socket-less .env can
  never yield a literal socket named "''" under systemd EnvironmentFile.
- start-agent-session.sh _tmux wrapper passes -L only when a socket is set;
  mosaic-agent@.service drops the socket default + uses a conditional ExecStop.

CONTAINMENT: all 6 shipped presets set socket_name: mosaic-factory explicitly,
so they are unaffected — only socket-less rosters (the PoC) get default-socket
behavior. DEFAULT_SOCKET_NAME exported as a constant for explicit isolation.

Verified: 158 fleet + 201 fleet-adjacent tests green (socketArgs none/named,
model_hint→env, explicit-socket renders -L, socket-less bare env); shell bash -n
+ end-to-end sim (socket-less→no -L, model→--model); tsc/eslint/prettier/
sanitize clean.

Refs #626

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EsgTQzV5YUGk1JtCLP4B83
2026-06-22 13:26:25 -05:00
..

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:

~/.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:

~/.config/mosaic/fleet/agents/<agent>.env

Example:

MOSAIC_TMUX_SOCKET=mosaic-factory
MOSAIC_AGENT_RUNTIME=claude
MOSAIC_AGENT_WORKDIR=$HOME/src/your-project
# Optional escape hatch for PoC/canary agents:
# MOSAIC_AGENT_COMMAND=mosaic yolo claude

Manual canary sequence

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.