# Spec-Driven Development (SDD)

How we turn a feature idea into merged, traceable code in this repo. SDD layers a uniform,
machine-readable front-end onto the workflow we already run (Gitea issues → branch/PR →
multi-persona review → red/green TDD). It does not replace any of that — see
[ADR-041](./docs/adr/041-sdd-adoption.md) for the why.

- **The rules** live in [`.specify/constitution.md`](./.specify/constitution.md) (humans) and
  [`.specify/AGENTS.md`](./.specify/AGENTS.md) (AI agents, every invocation).
- **The templates** live in [`.specify/templates/`](./.specify/templates/).
- **The worked example** is [`.specify/features/_example/`](./.specify/features/_example/) — read it first.

---

## 1. The workflow in 8 steps

| # | Step | Who | Artifacts created / touched |
|---|---|---|---|
| 1 | **Idea → Gitea issue** using the Feature template | author | Gitea issue (labels `spec-required`, `needs-review`) from `.gitea/ISSUE_TEMPLATE/feature.md` |
| 2 | **Write the spec** — Context, User Journey, EARS `REQ-NNN` requirements, measurable acceptance criteria, Out of Scope | author | issue body **and** `.specify/features/<name>/spec.md` |
| 3 | **Add design artifacts** as needed | author | `design.md`; `api-contract.yaml` (any new endpoint); `threat-model.md` (uploads / new mutating endpoint / AI tool); feature-local `adr-NNN-*.md` or a `docs/adr/` entry for project-wide decisions |
| 4 | **Persona spec review** — the six checklists gate the spec | RE, Developer, Security, DevOps, UI/UX, Architect | `checklist-results.md` + the `## Persona Review Results` table; findings folded into the spec |
| 5 | **Resolve Open Questions & blocking FAILs** — spec does not proceed while any remain | author | spec updated; `Open Questions` emptied |
| 6 | **Decompose into tasks** in red/green order; seed the RTM | author | `tasks.md`; rows added to [`.specify/rtm.md`](./.specify/rtm.md) (`Status: Planned`) |
| 7 | **Implement** in a worktree, TDD per task (failing test → green → refactor → commit); agent reads `AGENTS.md` + `spec.md` + `api-contract.yaml` | implementer (often an AI agent) | code + tests; `npm run generate:api` after backend changes; RTM `Status` → `Done` |
| 8 | **PR → multi-persona PR review → merge**; archive the feature | reviewers | PR (`Closes #n`); on merge, move the feature dir under `.specify/features/_archive/<name>/` (or tag it shipped) |

The personas at step 4 review the **spec**; the same personas at step 8 (via the existing
`review-pr` / `deliver-issue` skills) review the **code**. Step 4 catches at spec time what
used to surface only at step 8.

## 2. How a Gitea issue becomes a spec

**Before (free-form issue):**

> **Title:** Add profile pictures
> Users should be able to upload a picture for their profile. Make sure it's not too big and
> only admins can remove other people's. Show initials if there's no picture.

Ambiguous: how big? which formats? what status code on rejection? what about unauthenticated
callers? No identifiers to trace, no measurable criteria.

**After (SDD-structured issue — excerpt):**

> **Title:** As a user I want to upload a profile picture so other family members recognise me
>
> **## Requirements**
> - **REQ-002** (Event-driven) — When an authenticated user sends `POST /api/users/me/avatar`
>   with a valid image, the user service shall store it and return a profile view with a
>   non-null `avatarUrl`.
> - **REQ-008** (Unwanted-behavior) — If the uploaded file exceeds 2 MB, then the user service
>   shall return `400 ErrorCode.AVATAR_TOO_LARGE` and store nothing.
> - **REQ-009** (Unwanted-behavior) — If a caller without `Permission.ADMIN_USER` targets
>   another user's avatar, then the system shall return `403 ErrorCode.FORBIDDEN`.
>
> **## Acceptance Criteria**
> - **REQ-008** — a 2.1 MB PNG returns `400 AVATAR_TOO_LARGE`; bucket object count unchanged.

Every behavior is now a uniquely-identified, testable, EARS-formed requirement with a
measurable acceptance criterion. See the full version in
[`.specify/features/_example/spec.md`](./.specify/features/_example/spec.md).

## 3. How to run a persona review

Each persona reads the spec, walks its checklist in `.specify/personas/<persona>.md`, and
posts a Gitea comment (or fills `checklist-results.md`) with **PASS / FAIL / QUESTION** per
item and a verdict. A `FAIL` from Security or Architect is a hard block. Concrete example:

> ### Security — Spec Review
>
> | # | Item | Status | Note |
> |---|---|---|---|
> | 1 | All mutating endpoints have authn + authz `If` clauses | PASS | REQ-006 (401), REQ-009 (403) |
> | 3 | Audit fields server-set, forbidden in body | **FAIL** | `avatarObjectKey` is bound from the request body → mass-assignment (CWE-639). Make it server-set in `UserService`. |
> | 6 | Upload type allow-list + size | PASS | REQ-007 / REQ-008 |
> | 9 | threat-model.md present & STRIDE-complete | **QUESTION** | Is the avatar URL public or proxied? If public S3, that's information disclosure. |
>
> **Verdict: CHANGES REQUESTED** — blocking FAIL: #3. Resolve #9 in the threat model.

The author folds the fix into the spec (here: server-set key + authenticated proxy URL),
empties the finding, and the persona re-reviews until `APPROVE`. This mirrors the existing
`review-issue` skill — the persona checklists just make the spec pass/fail explicit.

## 4. How the AI agent uses the spec

Once the spec is `APPROVE`d and tasks are seeded, the implementer points the agent at the
artifacts. Example prompt:

> Implement `.specify/features/profile-picture-upload/`. Read `.specify/AGENTS.md` and obey
> the constitution it references. The contract is `spec.md` (REQ-001…REQ-009) and
> `api-contract.yaml`. Work through `tasks.md` in order, red/green TDD — write the failing
> test named in each task first, confirm it fails, then make it pass. After backend model
> changes run `npm run generate:api`. Each REQ has a test in the Traceability table; do not
> mark a task done until its test is green. Update `.specify/rtm.md` Status as you go.

The agent now has: the rules (`AGENTS.md` → constitution), the exact requirements with ids,
the API shape, and a test-first task list — so its output is bounded and verifiable.

## 5. Maintenance rules

- **Constitution** ([`.specify/constitution.md`](./.specify/constitution.md)) — change it only
  when a project-wide rule genuinely changes. Bump the semantic version (MAJOR = rule
  removed/weakened, MINOR = rule added/tightened, PATCH = wording), run the §6 Sync Impact
  review, and let the `constitution-diff` CI job list the files to reconcile. Record the bump
  in ADR-041's revision log (or a superseding ADR for MAJOR).
- **AGENTS.md** — keep it under 200 lines. It cross-references the constitution; it must never
  duplicate or contradict it.
- **ADRs** — project-wide decisions go in [`docs/adr/`](./docs/adr/) (next free `NNN`, verify
  on disk). Immutable once `Accepted`; supersede, don't edit. Feature-local decisions stay
  beside the feature spec.
- **Feature specs** — archive on merge: move `.specify/features/<name>/` to
  `.specify/features/_archive/<name>/`. The spec stays as the record of what shipped.
- **RTM** ([`.specify/rtm.md`](./.specify/rtm.md)) — append rows when a spec is approved;
  flip `Status` as tests go green; never delete a shipped requirement's row. CI warns on drift.
- **Personas** — update `.specify/personas/*.md` checklists when a recurring blind spot
  appears; keep them aligned with the richer `.claude/personas/`.

## 6. Quick-start cheatsheet

**EARS patterns** (every requirement is one of these + a `REQ-NNN` id):

| Pattern | Shape |
|---|---|
| Ubiquitous | `The <system> shall <behavior>.` |
| Event-driven | `When <trigger>, the <system> shall <behavior>.` |
| State-driven | `While <state>, the <system> shall <behavior>.` |
| Optional-feature | `Where <feature/permission present>, the <system> shall <behavior>.` |
| Unwanted-behavior | `If <undesired condition>, then the <system> shall <response>.` |

**File locations:**

| What | Where |
|---|---|
| Non-negotiable rules | `.specify/constitution.md` |
| Agent rules (read every time) | `.specify/AGENTS.md` |
| Templates | `.specify/templates/{feature-spec,adr,threat-model,api-contract-stub}.md` |
| Persona checklists | `.specify/personas/*.md` |
| In-flight feature | `.specify/features/<name>/{spec,design,tasks,checklist-results}.md` + `api-contract.yaml` + `threat-model.md` |
| Worked example | `.specify/features/_example/` |
| Traceability matrix | `.specify/rtm.md` |
| ADR archive | `docs/adr/NNN-*.md` |
| Issue templates | `.gitea/ISSUE_TEMPLATE/{feature,bug}.md` |
| CI gate | `.gitea/workflows/sdd-gate.yml` |

**Before you mark a feature done:** every `REQ-NNN` has a green test, the RTM Status is
`Done`, all six personas APPROVE, `npm run lint` and the targeted tests pass, and
`npm run generate:api` has been run if the backend model changed.

**Commands:**

```bash
# validate a contract locally (same as CI)
npx @stoplight/spectral-cli lint .specify/features/<name>/api-contract.yaml

# regenerate the TS client after a backend model/endpoint change
cd frontend && npm run generate:api   # backend must run with --spring.profiles.active=dev
```