Delegate Task 4 Lane Workaround

Delegate Task 4-Lane Workaround

Use when the user explicitly wants 4 parallel subagent lanes, but a single delegate_task(tasks=[...]) batch fails because the environment is capped at delegation.max_concurrent_children=3.

Problem

In this environment, sending 4 tasks in one delegate_task(tasks=[...]) call can fail with an error like:

Too many tasks: 4 provided, but max_concurrent_children is 3.

This happens before any task starts, so you do not get an automatic queue or partial execution.

Reliable workaround

To preserve true 4-lane parallelism:

1. Put 3 tasks into one batched delegate_task(tasks=[...]) call.
2. Put the 4th task into a separate single-task delegate_task(goal=...) call.
3. Launch those two delegate calls in parallel from the parent agent.
   • If available, use multi_tool_use.parallel.
4. Keep delegated tasks read-only when possible (terminal, file) and have the parent session do all persistent writes, GitHub comments, and artifact creation.

Best fit

This pattern is especially useful for:

• adversarial plan-review sweeps
• issue triage across multiple independent items
• read-only repo audits where each lane produces a verdict or checklist

Example pattern

Parent launches in parallel:

• Call A: delegate_task(tasks=[task1, task2, task3])
• Call B: delegate_task(goal=task4)

Then the parent:

• aggregates the returned summaries
• writes canonical review artifacts
• posts GitHub comments
• updates local tracking docs

Why this is better than serial fallback

If the user asked for "4 at a time," dropping to 3 serially changes throughput and intent. Splitting into 3 + 1 preserves the requested concurrency without requiring config changes.

Cautions

• Do not use delegated children for repo writes you need to persist.
• Be explicit about paths, issue numbers, and output schema because child summaries are compressed.
• If the task is data-gathering-heavy rather than reasoning-heavy, prefer execute_code instead of more subagents.
• Treat subagent timeouts as recoverable orchestration failures, not task failure. If one or more read-only lanes time out, immediately continue in the parent with direct gh/git/search/read-file grounding for the missing facts, then record which lanes timed out in the handoff. Do not let a timed-out research lane block obvious safe closeout actions that have been independently verified in the parent session.