Dispatching Parallel Agents

Assign separate agents to independent problem domains simultaneously for faster resolution.

When to Use

• 3+ test failures across different files/subsystems
• Multiple independent tasks that don't share state
• Investigations that won't interfere with each other
• Failures from unrelated root causes

When NOT to Use

• Failures are interconnected
• Tasks share state or create conflicts
• Agents would modify the same files
• You lack context to properly scope tasks

Implementation Steps

1. Group by Domain

Organize failures/tasks into independent categories:

Group A: Authentication tests (3 failures)
Group B: API endpoint tests (2 failures)
Group C: UI component tests (4 failures)

2. Define Focused Tasks

Each agent receives:

3. Dispatch Concurrently

IMPORTANT: Launch all tasks in a single message (no run_in_background). Multiple Task calls in the same message automatically run in parallel, and Claude waits for all to complete.

# All three tasks run in parallel automatically when in the same message
Task(test-engineer, prompt="Fix auth test failures in src/auth/*.test.ts")
Task(test-engineer, prompt="Fix API test failures in src/api/*.test.ts")
Task(frontend-developer, prompt="Fix UI test failures in src/components/*.test.tsx")
# Claude waits for all to complete, then continues

Avoid run_in_background: true unless you need to do other work while waiting. Task IDs must be captured and used within the same response.

4. Integrate Results

1. Review all agent outputs (available after parallel completion)
2. Verify no conflicts between changes
3. Run full test suite
4. Merge changes

Effective Agent Prompts

Good prompt:

Fix the 3 failing tests in src/auth/login.test.ts:
- "should reject invalid email format"
- "should require password min length"
- "should handle network errors"

Error messages attached. Identify root causes - don't just increase timeouts.
Constraints: Don't modify src/api/* files.
Output: Summary of fixes with test results.

Bad prompt:

Fix all the tests

Prompt Template

## Task: [Specific description]

**Scope:** [Files/tests to focus on]

**Failures:**

- [Test name]: [Error message]
- [Test name]: [Error message]

**Goal:** [What success looks like]

**Constraints:**

- Don't modify [files]
- Preserve [behavior]

**Output:**

- Summary of root causes found
- Changes made
- Verification results

Common Pitfalls

Benefits

• Reduces investigation time through parallelization
• Each agent maintains narrow focus
• Minimizes cross-agent interference
• Solves multiple problems concurrently