greenfield-decomposer

name	greenfield-decomposer
description	Break down a greenfield project blueprint into executable task-creator-ready research documents. Use after greenfield-init has produced a project blueprint, or when a project plan needs to be decomposed into buildable chunks with validation gates.

Greenfield Decomposer

Recursively break down project blueprint phases into task-creator-ready research documents.

When to Use

• A PROJECT_BLUEPRINT.md exists from greenfield-init
• You need to decompose a specific phase into executable work
• Work items are too large for task-creator to handle directly

Input Requirements

1. Project path — The .agent-tasks/tasks/[YYYYMMDD-project-name]/ folder
2. Phase — Which phase to decompose (or "next" to pick the first incomplete phase)

Behavior

1. Read the Guides

Read and internalize (located in this skill folder):

• DECOMPOSITION_GUIDE.md — Rules for breaking phases into chunks
• VALIDATION_GATES.md — Standard validation patterns per task type

2. Read Project Context

Read from the project folder:

• research/PROJECT_BLUEPRINT.md — Full project plan
• research/API_CONTRACT.md — Interface contract (if it exists)
• Any existing phase research docs (to understand what's already been decomposed)
• Any completed tasks (for context on what's already built)

3. Decompose the Phase

For the target phase:

1. List the work — Everything that needs to happen in this phase
2. Categorize each item using categories from DECOMPOSITION_GUIDE.md:
   • Scaffolding, Models, Endpoints, Components, Integration, Configuration
3. Order by dependency — What depends on what within the phase
4. Size check each item — Can a single sub-agent complete this in one session?
   • Yes → It's task-creator-ready
   • No → Break it down further, then size check again

4. Attach Validation Gates

Every work item gets a validation gate from VALIDATION_GATES.md:

• Executable — A command, a request, or a visible result
• Binary — Pass or fail, no subjective judgment
• Immediate — Verifiable right after the work is done

5. Identify Parallel Tracks

Within the phase, determine what can run in parallel:

• Items with no shared dependencies can be parallelized
• Items touching the same files must be sequential
• Frontend and backend items referencing the API contract can be parallel
• Group parallel items explicitly in the research document

6. Produce Research Document

Write a research document for the phase to: research/PHASE-[N]-[phase-name].md

This document is the input for task-creator. Structure it so task-creator can read it and produce task files directly.

Research Document Format

# Phase [N]: [Phase Name]

**Source:** PROJECT_BLUEPRINT.md, Phase [N]
**Goal:** [Phase goal from blueprint]
**Validation gate:** [Phase-level gate from blueprint]

---

## Work Items

### [N.1] [Item Name]

**Category:** [scaffolding/models/endpoints/components/integration/config]
**Dependencies:** None | [Item N.X]
**Parallel with:** [Item N.X] | None

**What to do:**
[Clear description of the work]

**Scope:**
[Files/directories involved]

**Validation:**
- [ ] [Executable gate]

---

### [N.2] [Item Name]
...

## Execution Order

1. Items N.1-N.3 can run in parallel (no shared dependencies)
2. Item N.4 depends on N.1 completing
3. ...

## Phase Complete When

- [ ] All work items complete
- [ ] Phase validation gate passes: [gate from blueprint]

7. Hand Off

After producing the research document:

Phase [N] decomposed into [X] work items. Next step: use the task-creator skill to generate task files.

Use the task-creator skill to generate tasks from:
- task: [YYYYMMDD-project-name]
- Source: .agent-tasks/tasks/[YYYYMMDD-project-name]/research/PHASE-[N]-[phase-name].md

Decomposition Rules

The "Single Session" Test

A chunk is small enough when a sub-agent can:

1. Read the task
2. Make the changes
3. Verify the result
4. All within a single conversation session

If a chunk requires the agent to "come back later" or "check after restart", it's too big.

The "Runnable System" Rule

After all tasks in a phase are complete, the system must be in a runnable state. Never leave the system broken between phases.

Recursion Depth

Level	Artifact	Produced by
Blueprint	Phases	greenfield-init
Phase	Work items	greenfield-decomposer
Work item	Task files	task-creator
Task file	Execution	task-orchestrator

If a work item is still too large, break it into sub-items at the same level. Flatten into sequential work items with dependencies — do not create deeper nesting.

One Phase at a Time

Decompose and complete one phase before starting the next. This ensures the validation gate passes and the system is in a known-good state before building on top of it.

Quality Checklist

Before finalizing a phase research document:

• Every item passes the "single session" test
• Every item has a validation gate
• Items are ordered by dependency
• Parallel tracks are identified and labeled
• The phase ends with a runnable system
• Document follows the research document format above