Dispatching Parallel Agents

Dispatching Parallel Agents

Overview

When you have multiple unrelated failures or independent tasks, investigating them sequentially wastes time. Each investigation is independent and can happen in parallel.

Core principle: Dispatch one agent per independent problem domain. Let them work concurrently.

Announce at start: "I'm using dispatching-parallel-agents to handle these independent tasks."

When to Use

Use when:

• 3+ test files failing with different root causes
• Multiple subsystems broken independently
• Independent tasks in an implementation plan
• Each problem can be understood without context from others
• No shared state between investigations

Don't use when:

• Failures are related (fix one might fix others)
• Need to understand full system state
• Agents would interfere with each other (editing same files)

The Pattern

1. Identify Independent Domains

Group tasks/failures by what's broken:

• Backend API: UserService issues
• Frontend: Component rendering issues
• Database: Migration problems

Each domain is independent - fixing UserService doesn't affect component tests.

2. Create Focused Agent Tasks

Each agent gets:

• Specific scope: One test file, one component, one service
• Clear goal: Make these tests pass / implement this feature
• Constraints: Don't change other code
• Expected output: Summary of what you found and fixed

3. Dispatch in Parallel

Task("Fix UserService.GetById null reference - backend/tests/UserServiceTests.cs")
Task("Fix UserCard component not rendering - frontend/src/components/__tests__/UserCard.test.tsx")
Task("Fix migration rollback issue - backend/Migrations/")
// All three run concurrently

4. Review and Integrate

When agents return:

• Read each summary
• Verify fixes don't conflict
• Run full test suite
• Integrate all changes

Agent Prompt Structure

Good agent prompts are:

1. Focused - One clear problem domain
2. Self-contained - All context needed to understand the problem
3. Specific about output - What should the agent return?

Example prompt:

Fix the 3 failing tests in backend/HybridFit.Api.Tests/Services/CoachServiceTests.cs:

1. "GetCoachById_WithInvalidId_ReturnsNull" - expects null but throws exception
2. "CreateCoach_WithDuplicateEmail_ThrowsConflict" - wrong exception type
3. "UpdateCoach_WithNonExistent_ReturnsNotFound" - test timing out

Your task:
1. Read the test file and understand what each test verifies
2. Identify root cause using systematic-debugging
3. Fix the issues following TDD
4. Run tests to verify

Return: Summary of root cause and what you fixed.

Common Mistakes

Too broad: "Fix all the tests" - agent gets lost Specific: "Fix CoachServiceTests.cs" - focused scope

No context: "Fix the race condition" - agent doesn't know where Context: Paste the error messages and test names

No constraints: Agent might refactor everything Constraints: "Do NOT change production code" or "Fix tests only"

When NOT to Use

• Related failures: Fixing one might fix others - investigate together first
• Need full context: Understanding requires seeing entire system
• Exploratory debugging: You don't know what's broken yet
• Shared state: Agents would interfere (editing same files)

Integration with Other Skills

Works well with:

• executing-plans — Parallel strategy for independent tasks
• systematic-debugging — Each agent uses this for their domain

After parallel work:

• Run layered-review on combined changes
• Use verification before claiming complete