Module 08: SDLC
Run a software change through the full lifecycle: problem, design, build, test, review, release, observe, and learn.
The Mental Model
Section titled “The Mental Model”SDLC is the professional control system for change.
problem -> requirements -> design -> implementation -> verification -> release -> monitoring -> retrospectiveWithout SDLC, teams confuse activity with progress.
Analogy
Section titled “Analogy”SDLC is like constructing a bridge. You do not start pouring concrete because someone said “make crossing faster.” You survey, design, calculate load, build, inspect, open traffic, monitor cracks, and maintain it.
Lifecycle Stages
Section titled “Lifecycle Stages”| Stage | Output |
|---|---|
| Discovery | Problem statement and user workflow |
| Requirements | Acceptance criteria and constraints |
| Design | Architecture, data, API, risks |
| Planning | Tasks, owners, order |
| Build | Code and docs |
| Test | Evidence of behavior |
| Review | Risk reduction |
| Release | Deploy and rollback plan |
| Observe | Logs, metrics, user feedback |
| Learn | Retrospective |
Feature Scenario
Section titled “Feature Scenario”“Agents can summarize ticket history and draft a response, but a human must approve before anything is sent.”
This is not just an AI feature. It touches:
- Data access.
- Prompt/context construction.
- Model failure.
- Human approval.
- Audit logs.
- Privacy.
- UI state.
- Cost.
- Deployment.
Visual: Human Approval Flow
Section titled “Visual: Human Approval Flow”human approval state machine
RequestedUser or system asks for a draft.
Draft generatedAI output exists, not trusted yet.
Human reviewPerson checks correctness and tone.
ApprovedAllowed to send.
SentFinal action is recorded.
Rejected drafts go to EditedEdited drafts return to Human reviewEvery transition writes audit history
Agentic Angle
Section titled “Agentic Angle”Use an agent for design critique:
Review this SDLC plan for an AI-assisted support response feature. Find missingrequirements, privacy risks, human approval gaps, audit gaps, tests, releaserisks, and monitoring requirements.Questions
Section titled “Questions”- What user pain does the feature solve?
- What data should the model see?
- What should never be automated?
- What must be audited?
- What tests prove approval is required?
- What monitoring catches bad model behavior?
- What rollback disables the feature safely?
- Create
portfolio/08-sdlc/design-doc.md. - Write a problem statement.
- Write acceptance criteria.
- Draw the approval flow.
- Write a data access policy.
- Write a test plan.
- Write a release plan.
- Write a rollback plan.
- Ask an agent to critique the plan.
- Revise it.
Done When
Section titled “Done When”- The feature is scoped.
- Human approval is enforceable.
- Privacy and audit are addressed.
- Tests and release gates are defined.
- Rollback is clear.