| 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)