background-agents

name	background-agents
description	This skill should be used when the user asks about "parallel agents", "background tasks", "run_in_background", "non-blocking agents", "check agent progress", "TaskOutput", "retrieve agent results", or discusses running multiple agents concurrently. Covers patterns for launching agents in background, monitoring progress, and retrieving results.
version	1.0.0

Background Agents - Non-Blocking Parallel Execution

Background agents let you continue working while long-running tasks execute. Use run_in_background: true to launch agents that run without blocking.

When to Use Background Agents

• Research phases with multiple independent agents
• Pre-commit reviews (code-simplifier + kieran reviewer)
• Any Task that takes >30 seconds and doesn't gate your immediate next step

Launching Background Agents

Add run_in_background: true to Task calls:

Task(
  subagent_type="compound-engineering:review:kieran-typescript-reviewer",
  prompt="Review the changes in this PR",
  max_turns: 20,
  run_in_background: true
)

Parallel Launch Pattern

Launch multiple agents in ONE message for true parallelism:

# Single message with multiple Task calls
Task 1: subagent_type="pr-review-toolkit:code-simplifier" (max_turns: 15, run_in_background: true)
Task 2: subagent_type="compound-engineering:review:kieran-typescript-reviewer" (max_turns: 20, run_in_background: true)

Monitoring Progress

Check All Tasks

• /tasks - List all background tasks with status
• Ctrl+T - Toggle task list view in terminal

Check Specific Task

TaskOutput(task_id="task-abc123", block=false)

Returns current output without waiting for completion.

Retrieving Results

Wait for Completion

TaskOutput(task_id="task-abc123", block=true)

Blocks until agent completes, returns full output.

Read Output File

Background agents write to output files. The path is returned when you launch:

Task returned: { task_id: "abc123", output_file: "/path/to/output.txt" }

Use Read tool on output_file path to check progress or results.

Common Patterns

Pre-Commit Reviews

# Launch both reviewers in parallel
Task(subagent_type="pr-review-toolkit:code-simplifier", run_in_background: true)
Task(subagent_type="compound-engineering:review:kieran-typescript-reviewer", run_in_background: true)

# Continue polishing code while they run...

# Check progress
/tasks

# Retrieve results when ready
TaskOutput(task_id="...", block=true)

Research Phase

# Launch all research agents
Task(subagent_type="somto-dev-toolkit:prd-codebase-researcher", run_in_background: true)
Task(subagent_type="compound-engineering:research:git-history-analyzer", run_in_background: true)
Task(subagent_type="somto-dev-toolkit:prd-external-researcher", run_in_background: true)

# Continue interview prep while research runs...

# Retrieve all results
TaskOutput(task_id="task-1", block=true)
TaskOutput(task_id="task-2", block=true)
TaskOutput(task_id="task-3", block=true)

When NOT to Background

• Complexity estimator (Phase 5.5) - Need result immediately for next phase
• Any agent whose output gates the next step - Must wait for result
• Quick agents (<10 seconds) - Overhead not worth it

Kieran Reviewers by Language

Language	Agent
TypeScript/JavaScript	compound-engineering:review:kieran-typescript-reviewer
Python	compound-engineering:review:kieran-python-reviewer
Ruby/Rails	compound-engineering:review:kieran-rails-reviewer

Domain-Specific Reviewers

Domain	Agent
Database/migrations	compound-engineering:review:data-integrity-guardian
Frontend races	compound-engineering:review:julik-frontend-races-reviewer