SDD Explain

SDD Explain

Explain Spec-Driven Development (SDD) with a CLI-first mental model. Use this skill to teach lane selection, phase flow, and how workflow skills and ae sdd commands work together.

Required Skills

• spec-driven-development
• research

Instructions

1. Identify Intent: Determine whether the user wants a quick overview, lane guidance, or a deep dive on one phase/​command.

2. Why SDD: Explain the three outcomes:

   • Clarity: behavior is defined before implementation drift
   • Traceability: tasks and code map back to specs
   • Confidence: reconcile/​validation checks prove intent matches implementation

3. CLI-First Operating Model:

   • Change sets are initialized with ae sdd init <name> --lane <full|vibe|bug>.
   • Progress is tracked with ae sdd status [name] and ae-sdd-next [name].
   • Full-lane implementation uses ae sdd task list|start|complete|complete --next.
   • Use ae sdd spec list to discover canonical spec paths before reading or editing canonical specs.
   • Workflow skills (ae-sdd-init, ae-sdd-proposal, ae-sdd-specs, ae-sdd-tasks, etc.) are assistants; the CLI is the source of truth for state transitions.

4. Deterministic Full-Lane Loop (Plan <-> Implement):

   • Explain this exact loop until all tasks are complete:
     1. ae-sdd-plan prepares the current task plan (task is selected via CLI task commands)
     2. ae-sdd-next advances plan -> implement
     3. ae-sdd-implement executes and completes the current task via ae sdd task complete
     4. ae-sdd-next decides transition deterministically using CLI guards:
        • remaining tasks: loop implement -> plan
        • all tasks complete: advance implement -> reconcile
   • Emphasize that workflow commands do not manually force phase transitions.

5. Lane Flows:

   • Full: proposal -> specs -> discovery -> tasks -> plan -> implement -> reconcile -> finish
   • Vibe: context -> plan -> implement -> [reconcile -> finish]
   • Bug: triage -> plan -> implement -> [reconcile -> finish]

6. Change Set Structure:

   changes/<name>/
     state.toml      # lane, phase, notes, pending
     proposal.md     # full lane proposal
     context.md      # vibe/​bug context when needed
     docs/​specs/     # behavior contracts (default; configurable via .ae-config.json specRoot)
     thoughts/       # discovery notes
     tasks.toml      # ordered tasks with spec_requirements
     plans/          # implementation plans
   

7. Command Map:

   Command	Use For
   ae sdd init	Create a new change set
   ae sdd status	See current lane/​phase/​tasks
   ae-sdd-next	Verify current-phase artifacts, then advance phase
   ae sdd task start	Start next full-lane task
   ae sdd task current	Show active in-progress task
   ae sdd task next	Show next pending task
   ae sdd task complete	Complete current in-progress task
   ae sdd task complete --next	Finish and chain tasks
   ae sdd phase complete --next	Underlying guarded transition used by ae-sdd-next
   ae sdd phase set	Manual override only by explicit user request
   ae sdd notes set	Persist resume context/​decisions
   ae sdd pending add/​clear	Track unresolved blockers
   ae sdd spec list	List canonical specs
   ae sdd config init	Initialize .ae-config.json
   ae-sdd-init	Derive and approve a new change-set name, then initialize
   ae-sdd-continue	Resume an existing change set from CLI status
   ae-sdd-vibe	Start or continue vibe-lane exploratory work
   ae-sdd-bug	Triage and initialize bug-lane fixes
   ae-sdd-proposal	Draft and refine proposal
   ae-sdd-specs	Create/​update specs
   ae-sdd-discovery	Validate architecture and risks
   ae-sdd-tasks	Build tasks.toml from specs
   ae-sdd-plan	Create execution plans
   ae-sdd-implement	Execute planned work
   ae-sdd-critique	Review artifacts for quality and gaps
   ae-sdd-scenario-test	Validate behavior using realistic scenarios
   ae-sdd-commit	Craft commit(s) aligned to SDD progress
   ae-sdd-reconcile	Verify implementation vs specs
   ae-sdd-finish	Close out change set
   ae-sdd-explain	Teach SDD concepts and workflow usage

8. How To Guide Users:

   • Recommend lane choice based on risk and ambiguity.
   • Explain next command, why it is next, and what artifact it should produce.
   • Use research for repo-specific details when asked how current code behaves.

Success Criteria

• User understands when to use full vs vibe vs bug lane.
• User understands that ae sdd CLI drives state and phase progression.
• User can name the next command and expected artifact in their current phase.

Usage Examples

Explain CLI + command relationship

"Use ae-sdd-specs to draft the contract, then run ae-sdd-next when you want to advance phases."

Followup Question

[!IMPORTANT] End by asking one focused follow-up: "Do you want a lane recommendation for your current task, or a step-by-step walkthrough of your current phase?"