slice-lifecycle

name	slice-lifecycle
description	This skill should be used when the user asks "what is a slice", "slice phases", "how do slices work", "slice workflow", or needs to understand the slice delivery lifecycle. Covers four phases: requirements, design, implementation, and completion with phase gates and review.

Slice Lifecycle

Overview of Forge slice lifecycle. Slices are the delivery phase — designing, implementing, and shipping focused deliverables.

What is a Slice?

Slice: Focused deliverable with clear scope and timeline. Input: Requirements from effort (or standalone). Output: Working software shipped to users. Duration: Days to weeks (time-boxed). Location: .forge-context/slices/YYYYMM-{slug}/

Example slices:

• Add OAuth login support
• Migrate database to new schema
• Implement export feature

Slice Phases

Phase 1: Requirements

Command: /forge:requirements

Actions:

• Define what you're building
• Define success criteria
• Identify affected components (area owners)
• Resolve open questions

Output:

• requirements.md with:
  • Summary
  • Success criteria
  • Scope (in/out)
  • Affected components
  • Open questions

Review: Create PR for area owner review and approval

Phase 2: Design

Command: /forge:design

Actions:

• Design architecture
• Make technical decisions (ADRs)
• Break down into tasks
• Plan testing strategy

Output:

• design.md with:
  • Architecture overview
  • Integration points
  • Task breakdown (T1, T2, T3...)
  • Testing strategy
  • Key decisions (ADRs)
• tasks.md structure prepared

Review: Create PR for area owner review and approval

Phase 3: Implementation

Command: /forge:start-task

Actions:

• Create tickets from task breakdown
• Implement each task in isolated worktree
• Write tests
• Create PRs

Output:

• Implementation PRs
• tasks.md updated with status

Review: Per-task code review

Phase 4: Completion

Command: /forge:phase-complete

Actions:

• Verify all tasks complete
• Run integration tests
• Update slice status

Output:

• Phase completion PR
• Slice marked complete

Review: Final completion PR

Slice File Structure

.forge-context/slices/YYYYMM-{slug}/
  requirements.md         # What we're building
  design.md               # How we're building it
  tasks.md                # Task breakdown + status
  decisions.md            # ADRs
  checklist.md            # Phase tracking
  artifacts/              # Supporting materials
    retrospective-notes.md

Slice Status Tracking

Slice status is tracked in tasks.md (per-task status) and checklist.md (phase completion tracking with dates).

tasks.md Snapshot:

| Task | Description | Status | PR |
|------|-------------|--------|-----|
| T1 | Add auth model | ✅ | #42 |
| T2 | Add auth API | 🔄 | - |

Phase Transitions

Requirements → Design:

• Requirements approved by area owners
• All open questions resolved
• Scope frozen

Design → Implementation:

• Design approved by area owners
• Task breakdown complete

Implementation → Complete:

• All tasks done
• Tests passing

Phase gates: Each phase requires PR approval before next phase begins.

When to Create a Slice

Create slice when:

• Clear deliverable identified
• Requirements are understood
• Scope is bounded
• Can ship in 1-3 weeks

Defer to effort when:

• Problem space unclear
• Discovery work needed
• Multiple deliverables
• Requirements gathering required

Slice Workflows

Standalone Slice (No Effort)

1. /forge:work new
2. /forge:requirements
3. /forge:design
4. /forge:start-task (per task)
5. /forge:phase-complete

Slice from Effort

1. /forge:work new (from effort candidate)
2. /forge:requirements (refine from effort)
3. /forge:design
4. /forge:start-task (per task)
5. /forge:phase-complete

Integration with Forge Workflows

Slice Commands

• /forge:work new — Initialize slice
• /forge:requirements — Requirements phase
• /forge:design — Design phase
• /forge:start-task — Implement task
• /forge:phase-complete — Complete phase
• /forge:process-pr-discussions — Process PR feedback

Agents

• requirements-gatherer — Requirements phase
• designer — Design phase
• implementation-worker — Implement tasks
• code-reviewer — Review PRs
• phase-completer — Phase completion

Summary

Phase	Command	Output	Review
Requirements	/forge:requirements	requirements.md	Approval
Design	/forge:design	design.md, tasks.md	Approval
Implementation	/forge:start-task	Code PRs	Per-task
Complete	/forge:phase-complete	Phase PR	Approval

Key principles:

• Phase gates (approval before next phase)
• Area owner review (domain expertise validation)
• Isolated work (worktrees per task)
• Evidence-based completion (tests + verification)