Subagent Batching

Patterns for parallel subagent execution. Use your judgment on batch sizes based on task complexity.

When to Parallelize

Parallelize when:

• •Processing multiple independent items (PRs, issues, files)
• •Tasks have no dependencies between items
• •Each item can succeed or fail independently

Don't parallelize when:

• •Later items depend on earlier results
• •Shared resources could cause conflicts
• •You need to aggregate results before proceeding

Launch Pattern

Launch subagents in a single message with multiple Task tool calls. Don't launch sequentially.

# Correct: ONE message with multiple Task calls
Task 1: Process item A
Task 2: Process item B
Task 3: Process item C
# All launch simultaneously

Batching for Large Sets

For many items, batch them and validate between batches:

1. •Launch a batch of subagents in parallel (single message)
2. •Wait for all to complete using TaskOutput with block=true
3. •Validate results before proceeding
4. •Start next batch after validation

Subagent Prompts

Give each subagent focused context:

• •Clear task description
• •Relevant identifiers and locations
• •Expected output format
• •Success criteria

Error Handling

• •One failure shouldn't block the rest
• •Mark failed items for human review
• •Continue processing remaining items
• •Provide summary of successes and failures

Reporting

After completion, summarize:

• •Total items processed
• •Successes with brief descriptions
• •Failures with reasons
• •Any required follow-up actions