Skip to main content

Spec-Driven Development (SDD)

SDD is the operating rhythm for LeanSpec: capture intent in a spec, let humans and AI execute from it, and keep the spec in sync.

Five Loop Stages​

  1. Discover — search existing specs before starting new work.
  2. Plan — create or update a spec so intent is unambiguous.
  3. Implement — humans and AI agents follow the spec to build.
  4. Validate — run tests and lean-spec validate to ensure quality.
  5. Update — mark the status, lessons, and follow-ups.

The loop restarts whenever new information appears. Specs are living documents, not ceremonial paperwork.

Roles in the Workflow​

  • Author clarifies the problem and desired outcome.
  • Implementer (human or AI) executes the plan.
  • Reviewer checks success criteria before status changes.

Tooling Support​

  • lean-spec list, search, and view for discovery.
  • lean-spec create and update for planning/status.
  • lean-spec validate and the MCP server for automation.

See Also​