name: orchestrating-parallel-tasks
description: Decomposes complex or large-scale requirements into discrete, mutually exclusive sub-tasks that can be executed in parallel by multiple agents. Use when a task is described as an "epic", spans multiple architectural layers, or would benefit from concurrent development to reduce time-to-completion.

SOP: Orchestrating Parallel Tasks

Purpose

Provides a systematic workflow for breaking down "epic-level" requirements into independent sub-tasks. This approach maximizes agent efficiency, enables parallel execution, and minimizes merge conflicts by ensuring clear functional and file-level boundaries.

Workflow Checklist

• [ ] Step 1: Contextual Analysis
• [ ] Identify high-level architectural layers involved (UI, API, Data, Auth, etc.).
• [ ] List existing files likely to be impacted.
• [ ] Identify external dependencies (Third-party APIs, DB schemas).
• [ ] Step 2: Boundary Identification & Slicing
• [ ] Apply Vertical Slicing to group features by user value.
• [ ] Apply Interface-First slicing for shared components.
• [ ] Identify "Shared Core" vs. "Independent Leaves".
• [ ] Step 3: Mutual Exclusivity Enforcement
• [ ] Verify that no two sub-tasks target the same set of files for modification.
• [ ] Decouple shared utilities into their own prerequisite task.
• [ ] Define mock interfaces for cross-task dependencies.
• [ ] Step 4: Sub-Task Specification
• [ ] Draft a clear "Acceptance Criteria" for each sub-task.
• [ ] Define the "MVP Slice" for each task.
• [ ] Map out the dependency graph (which tasks must finish before others start).
• [ ] Step 5: User Validation
• [ ] Present the phased plan and task list to the user for approval.

Detailed Instructions

1. Vertical Slicing vs. Horizontal Slicing

When decomposing, prefer Vertical Slicing. Instead of "Frontend Task" and "Backend Task" (Horizontal), aim for "User Login Flow" (Vertical) which includes UI, API, and DB changes. This allows an agent to deliver end-to-end value independently.

2. The Mutual Exclusivity Rule

To enable parallel execution:

• File Isolation: If Task A and Task B both need to edit src/utils.ts, they are NOT mutually exclusive. Extract the shared changes into a Task 0: Preparation or sequence them.
• State Isolation: Ensure sub-tasks don't depend on shared global state that is being modified concurrently without a locking mechanism or interface.

3. Interface-First Development

If Task B depends on the output of Task A, define the interface (API contract, Typescript interface, or DB schema) as the first step. Once the interface is defined and committed, Task A and Task B can proceed in parallel using mocks or stubs.

Success Criteria

• All sub-tasks have non-overlapping primary file sets.
• Each sub-task has its own test plan and acceptance criteria.
• The dependency graph is acyclic and minimizes sequential bottlenecks.
• The breakdown is presented in a way that an agent can pick up any "Ready" task and execute it without further clarification.