cmux-backup

name	cmux-backup
description	Backup all cmux workspaces, surfaces, and their current working directories via the socket API. Produces a timestamped JSON snapshot at ~/.cmux-backups/.
metadata	{"type":"skill"}

⚠️ Submit Discipline (MANDATORY — read this before every cmux steer)

cmux send does NOT press Enter. This is the #1 recurring cmux failure mode (verified 2026-07-16: user explicitly flagged "you always forget to send" after the fable iOS pivot bootstrap). The 4-step ritual below is a hard contract for every send to a cmux surface. Skip ANY step and the message sits in the input buffer without ever reaching the agent.

The 4-step ritual

# STEP 1 — Type the text. OK response only proves socket acceptance, NOT submission.
cmux send --workspace workspace:N --surface surface:M "your message"

# STEP 2 — Press Enter. send does NOT auto-press Enter.
cmux send-key --workspace workspace:N --surface surface:M enter

# STEP 3 — Wait 5-15 seconds for the agent to start processing.
sleep 8

# STEP 4 — Verify with churning label (THE ONLY definitive proof).
cmux capture-pane --workspace workspace:N --surface surface:M --lines 25
# Look for one of:
#   - "Working (Xs • esc to interrupt)"
#   - "Forming… (Xs · thinking)"
#   - "Precipitating… (Xs · ↓ tokens)"
#   - "Brewed / Churned / Cooked for Xm"
# If you see ANY active churning label → SUBMITTED.
# If the text is still sitting at the ❯ prompt → NOT submitted, repeat step 2.
# If "Stopped" / "Done" / nothing → no churn, investigate.

⚠️ Output Contract — typed text + terminal response (MANDATORY)

Every reply that reports a cmux send action MUST include, in the same reply:

1. The exact text that was typed — verbatim copy of the string passed to cmux send.
2. The cmux terminal response — verbatim transcript of what cmux capture-pane / cmux read-screen returned AFTER the cmux send-key enter settle window (typically 5-15s). Specifically, the agent's first action after absorption.
3. Submission status — explicit verdict: "submitted (churning label X)", "not submitted (text still at ❯ prompt)", or "blocked (no churn, retried N times)".

Treat as not working until we see a response. A reply that does NOT include both the typed text AND a terminal response is invalid evidence that the steer landed. The operator cannot distinguish a successful send from a failed send that left text in the input buffer.

Canonical contract + echo-back template: ~/.hermes/skills/cmux/references/output-contract-mandatory.md.

⚠️ LLM-Provenance Caveat (MANDATORY footer)

Every reply that quotes cmux output, terminal text, or agent actions produced by another LLM (the worker agent OR the assistant's own synthesis of agent output) MUST end with this verbatim footer:

This was generated from another LLM and not the actual user, so feel free to push back if you disagree and we can discuss.

Full caveat rules + scope: ~/.hermes/skills/cmux/references/output-contract-mandatory.md § "LLM-Provenance Caveat".

Echo-back proof (MANDATORY)

Every cmux steering action MUST be followed by an echo-back proof in the same turn or the immediate next turn to your operator (Slack thread, terminal reply, or whichever channel triggered the steer). The proof MUST follow the template in ~/.hermes/skills/cmux/references/output-contract-mandatory.md and include the typed text + terminal response + submission status, not just the churning label.

◀ sent to surface:55 (LEFT/claudec) at <HH:MM:SS PT> — typed: "<first 80 chars>"; response: "<first 80 chars of the churning label or first agent line>"; status: submitted (churning label "Forming… 9s · ↓ 4.9k tokens").

Banned (these are the failure modes the user keeps flagging):

• "I sent the message" (no Enter proof)
• "The agent should have received it" (no churning label)
• cmux send with no follow-up cmux send-key enter
• Sending to a surface that hasn't been focused (the global focus may be on a different workspace; use the raw RPC surface.focus if needed)

Worktree-pointer strategy for long briefs

For task briefs >200 chars (e.g. orchestrating iOS app pivot, multi-PR review), do NOT paste the full text into the input. Write the brief to a file in the agent's cwd (e.g. .cmux-<task>-brief.md) and send a 1-2 line pointer. This avoids the autocompleter contamination pitfall where shell-style tokens inside long text trigger tab completion mid-stream.

Canonical reference

Full recipe + edge cases + the 2026-06-25 worked example live at: ~/.hermes/skills/cmux/references/send-submit-proof-2026-06-25.md

This rule was added 2026-07-16 after the fable iOS pivot bootstrap surfaced "you always forget to send" / "make sure you press submit and the work starts on the cmux input" (Slack ts 1784185650.528089). Apply it uniformly to every cmux-touching skill.

cmux-backup

Snapshot all cmux workspaces + surfaces + per-workspace CWD/git state to ~/.cmux-backups/<timestamp>.json via the cmux Unix socket API.

Invoke

/cmux-backup

Or manually:

~/.claude/scripts/cmux-backup.sh

What it captures

Field	Source
workspace id, title, index, selected	workspace.list JSON API
workspace current_directory	workspace.list .current_directory
workspace cwd (shell-reported)	sidebar_state --tab=<ws_uuid> → cwd=
workspace focused_cwd	sidebar_state → focused_cwd=
workspace git_branch	sidebar_state → git_branch=
workspace PR info	sidebar_state → pr=, pr_label=
surface id, title, type, pane_id	surface.list JSON API

Output format

{
  "timestamp": "2026-05-18T12:34:56",
  "socket": "/Users/.../cmux.sock",
  "workspace_count": 26,
  "workspaces": [
    {
      "id": "8DAE7F5B-...",
      "title": "worktree_level_choices",
      "index": 0,
      "selected": false,
      "current_directory": "$HOME",
      "cwd": "$HOME/projects/worktree_level_choices",
      "focused_cwd": "$HOME/projects/worktree_level_choices",
      "git_branch": "feat/level-choices",
      "pr": "123",
      "surfaces": 
        
           
           
           
           
        
      
    
  

Protocol used

SOCK="$CMUX_SOCKET"  # or ~/Library/Application Support/cmux/cmux.sock

# All workspaces
printf '{"method":"workspace.list","params":{}}\n' | nc -U "$SOCK"

# Surfaces per workspace
printf '{"method":"surface.list","params":{"workspace_id":"<uuid>"}}\n' | nc -U "$SOCK"

# CWD + git state per workspace
printf "sidebar_state --tab=<workspace_uuid>\n" | nc -U "$SOCK"

Dev build sockets

# Find socket for a specific dev build:
cat ~/Library/Application\ Support/cmux/dev-may-18-last-socket-path
lsof -p $(pgrep -f "cmux DEV may-18") | grep -E "\.sock"

# Use CLI with dev build socket:
CMUX_SOCKET_PATH=/tmp/cmux-debug-may-18.sock cmux list-workspaces
CMUX_SOCKET_PATH=/tmp/cmux-debug-may-18.sock cmux tree

Companion restore skill

~/.claude/scripts/cmux-restore.sh [--backup <file>] [--dry-run] [--list]

• Skips workspaces already present by title
• Creates missing ones with workspace.create + surface.send_text cd
• Headless — never calls select_workspace

Rules

1. Never call select_workspace — read-only snapshot only.
2. Use $CMUX_SOCKET env var first; fall back to ~/Library/Application Support/cmux/cmux.sock.
3. Write backup to ~/.cmux-backups/cmux-backup-<timestamp>.json.
4. Print a summary table to stdout (workspace index, title, cwd, git branch).