Skill: Cross-Machine Coordination Pattern

Skill ID: cross-machine-coordination Owner: Ralph (Work Monitor) Squad Integration: All agents Status: Design proposal — NOT implemented

⚠️ Not implemented. No Squad release reads .squad/cross-machine/, the cross_machine config block, or squad:machine-{name} labels. Ralph and squad watch do not poll task files, run whitelisted commands, or write result files. Everything below describes a proposed design, not current behavior. Do not tell users it works, and do not create task files expecting another machine to pick them up.

Use these instead:

• Several machines or pods running squad watch --execute on one repository: enable work claims (squad watch --execute --claims git-ref, or watch.claims in .squad/config.json). Claims are Git-ref leases that make sure only one watcher works on each issue. See ADR-002 (docs/specification/adr-002-work-claims-and-external-queues.md) and the "Multi-Machine Watch with Work Claims" docs scenario (docs/src/content/docs/scenarios/multi-machine-watch.md).
• Sending work to a machine with specific hardware: use capability routing with needs:* issue labels and a machine capabilities file.

Overview

Enables squad agents running on different machines (laptop, DevBox, Azure VM) to securely share work, coordinate execution, and pass results without manual intervention.

Pattern: Git-based task queuing + GitHub Issues supplement

Usage

For Task Sources (Orchestrating Machine)

To assign work to DevBox:

# Create task file
cat > .squad/cross-machine/tasks/2026-03-14T1530Z-laptop-gpu-voice-clone.yaml << 'EOF'
id: gpu-voice-clone-001
source_machine: laptop-machine
target_machine: devbox
priority: high
created_at: 2026-03-14T15:30:00Z
task_type: gpu_workload
payload:
  command: "python scripts/voice-clone.py --input voice.wav --output cloned.wav"
  expected_duration_min: 15
  resources:
    gpu: true
    memory_gb: 8
status: pending
EOF

# Commit & push
git add .squad/cross-machine/tasks/
git commit -m "Cross-machine task: GPU voice cloning [squad:machine-devbox]"
git push origin main

In this proposal (not implemented), Ralph on DevBox would:

1. Pull the task on next cycle (5-10 min)
2. Validate schema & command whitelist
3. Execute the GPU workload
4. Write result to .squad/cross-machine/results/gpu-voice-clone-001.yaml
5. Commit & push the result

For Task Executors (DevBox, Azure VMs)

In this proposal (not implemented), Ralph would watch .squad/cross-machine/tasks/ for work targeted at this machine. Ralph does not do this today.

On each cycle (5-10 min), as proposed:

# Pseudo-code (proposed Ralph implementation; does not exist)
1. git pull origin main
2. Load all .yaml files in .squad/cross-machine/tasks/
3. Filter for status=pending AND target_machine=HOSTNAME
4. For each task:
   a. Validate schema (must have: id, source_machine, target_machine, payload)
   b. Validate command against whitelist
   c. Execute task (with timeout)
   d. Write result to .squad/cross-machine/results/{id}.yaml
   e. Commit & push result

For Urgent/Ad-Hoc Tasks

Use GitHub Issues with squad:machine-{name} label:

# Create issue
gh issue create \
  --title "GPU: Clone voice profile from sample.wav" \
  --body "Execute voice cloning on DevBox. Input: /path/to/voice-input.wav" \
  --label "squad:machine-devbox" \
  --label "urgent"

In this proposal (not implemented), Ralph on DevBox would:

1. Detect issue with squad:machine-devbox label
2. Parse task from issue body
3. Execute task
4. Comment with result
5. Close issue

File Formats

Task File (YAML)

Location: .squad/cross-machine/tasks/{timestamp}-{machine}-{task-id}.yaml

Required Fields:

id: {task-id}                      # Unique identifier (alphanumeric + dash)
source_machine: {hostname}         # Where task was created
target_machine: {hostname}         # Where task will execute
priority: high|normal|low          # Execution priority
created_at: 2026-03-14T15:30:00Z   # ISO 8601 timestamp
task_type: gpu_workload|script|... # Category
payload:
  command: "..."                   # Shell command to execute
  expected_duration_min: 15        # Timeout (minutes)
  resources:
    gpu: true|false
    memory_gb: 8
    cpu_cores: 4
status: pending|executing|completed|failed

Optional Fields:

description: "Human-readable task description"
timeout_override_min: 120          # Override default timeout
retry_count: 3                     # Retry failed tasks

Result File (YAML)

Location: .squad/cross-machine/results/{task-id}.yaml

id: {task-id}                          # Links back to task
target_machine: devbox                 # Executed on
completed_at: 2026-03-14T15:45:00Z    # When it finished
status: completed|failed|timeout       # Outcome
exit_code: 0                           # Shell exit code
stdout: "..."                          # Captured output
stderr: "..."                          # Captured errors
duration_seconds: 900                  # How long it took
artifacts:
  - path: "/path/to/artifacts/..."   # Location of results
    type: audio|text|model|...
    size_mb: 2.5

Security Model

Validation Pipeline

All tasks go through:

1. Schema Validation
   • YAML structure matches spec
   • Required fields present
   • No unexpected fields (reject)
2. Command Whitelist
   • Only approved commands allowed
   • Path validation (no ../../ escapes)
   • Environment variable sanitization
   • No inline shell operators (&&, |, >)
3. Resource Limits
   • Timeout enforced (default: 60 min)
   • Memory cap: 16GB (adjustable)
   • CPU threads: 4 (adjustable)
   • Disk write: 100GB (adjustable)
4. Execution Isolation
   • Runs as unprivileged user
   • Temp directory cleaned after execution
   • Network access: read-only (no outbound writes)
5. Audit Trail
   • All executions logged to git
   • Commit signed with Ralph's key
   • Result stored immutably

Threat Mitigations

Configuration

Proposed .squad/config.json block. No Squad release reads it:

{
  "cross_machine": {
    "enabled": true,
    "poll_interval_seconds": 300,
    "this_machine": "devbox",
    "max_concurrent_tasks": 2,
    "task_timeout_minutes": 60,
    "command_whitelist": [
      "python scripts/voice-clone.py",
      "python scripts/data-process.py",
      "bash scripts/cleanup.sh"
    ],
    "result_ttl_days": 30
  }
}

Examples

Example 1: GPU Voice Cloning (Laptop → DevBox)

1. Laptop creates task:

# .squad/cross-machine/tasks/2026-03-14T1530Z-laptop-gpu-001.yaml
id: gpu-voice-clone-001
source_machine: laptop-machine
target_machine: devbox
priority: high
created_at: 2026-03-14T15:30:00Z
task_type: gpu_workload
payload:
  command: "python scripts/voice-clone.py --input voice.wav --output cloned.wav"
  expected_duration_min: 15
  resources:
    gpu: true
    memory_gb: 8
status: pending

2. Laptop commits & pushes:

git add .squad/cross-machine/tasks/
git commit -m "Task: GPU voice cloning [squad:machine-devbox]"
git push origin main

3. DevBox Ralph (5 min later):

[Ralph Watch Cycle]
- Pulled origin/main
- Detected: gpu-voice-clone-001 (status: pending, target: devbox)
- Validation: ✅ Schema OK, command whitelisted
- Executing: python scripts/voice-clone.py ...
- [15 minutes of processing]
- Completed: exit code 0
- Writing result...
- Committing & pushing...

4. Laptop Ralph (next cycle) sees result:

# .squad/cross-machine/results/gpu-voice-clone-001.yaml
id: gpu-voice-clone-001
target_machine: devbox
completed_at: 2026-03-14T15:45:00Z
status: completed
exit_code: 0
stdout: "Voice cloning completed. Output written to /tmp/cloned.wav"
stderr: ""
duration_seconds: 900
artifacts:
  - path: "/path/to/artifacts/voice-clone-001/output.wav"
    type: audio
    size_mb: 2.5

Example 2: Urgent Debug Request (Human → DevBox via Issue)

Create issue:

gh issue create \
  --title "DevBox: Debug voice model failure" \
  --body "Error: Model failed to load on last run. Please check /tmp/model.log and report findings." \
  --label "squad:machine-devbox" \
  --label "urgent"

DevBox Ralph detects → executes → comments:

✅ Executed on devbox at 2026-03-14 15:47:00
Command: python scripts/debug-model.py

Result:
------
Model file: /tmp/model-v2.bin (OK)
Checksum: a1b2c3d4e5f6 (matches expected)
Memory available: 12 GB (sufficient)

ERROR FOUND: Config file permission issue
  - File: ~/.config/voice/model.yaml
  - Permissions: -rw------- (owner-only)
  - Expected: -rw-r--r-- (world-readable for service)

FIX: Run: chmod 644 ~/.config/voice/model.yaml

Error Handling

Task Execution Failures

If a task fails (exit code != 0):

1. Result written with status: failed + exit code
2. stderr captured in result
3. Committed to git for audit
4. Source machine can retry by re-pushing task with status: pending

Stalled Tasks

If a task doesn't complete within timeout:

1. Process killed
2. Result written with status: timeout
3. stderr: "Execution exceeded X minutes"
4. Source can investigate or retry

Network Failures

If git push/pull fails:

• Ralph retries on next cycle
• Tasks queue locally until connectivity restored
• No tasks lost (stored in local repo)

Monitoring & Debugging

Check Task Queue

ls -la .squad/cross-machine/tasks/
cat .squad/cross-machine/tasks/*.yaml | grep -E "^(id|status|target_machine):"

Check Results

ls -la .squad/cross-machine/results/
cat .squad/cross-machine/results/{task-id}.yaml

View Execution History

git log --oneline .squad/cross-machine/ | head -20

Monitor Ralph Cycles

tail -f .squad/log/ralph-watch.log | grep "cross-machine"

Integration with Ralph Watch

Not implemented: squad watch does not include this pattern. The proposed watch loop was:

Proposed Ralph Watch Cycle (every 5-10 min):
1. Fetch GitHub issues with squad:machine-* labels
2. Poll .squad/cross-machine/tasks/
3. For each matching task:
   - Validate
   - Execute
   - Write result
   - Commit & push
4. Update status in issue (if applicable)
5. Sleep until next cycle

Until this is built, task files and squad:machine-* labels do nothing. To stop several watchers from picking the same issue, use work claims (--claims git-ref, ADR-002).

Migration from Manual Handoff

Before (today):

• Laptop → user manually copies file to Teams chat
• user pastes into target terminal
• user copies output back
• user pastes result manually

After (if this proposal is built):

• Laptop Ralph writes task file → git push
• DevBox Ralph auto-executes → git push result
• Laptop Ralph auto-reads result
• 0 human intervention needed

Future Enhancements

Potential expansions (Phase 2+):

1. Task Priorities: Execution order based on priority field
2. Serial Pipelines: Machine A → B → C task chains
3. GPU Availability Polling: Query DevBox before submitting work
4. Cost Tracking: Log resource usage per task
5. Notification Webhooks: Alert on task completion
6. Web Dashboard: Real-time task status visualization

Questions?

Refer to research report: research/active/cross-machine-agents/README.md

Contact: the research and documentation owner or Ralph (Work Monitor)