---
name: builder-workflow
description: "Phase-level implementation workflow for builder agents. Handles reading phase files, finding references, invoking domain skills, implementing all steps, and running verification (tests + typecheck). Preloaded into builder agents via skills: field — not user-invocable."
user-invocable: false
metadata:
  version: 1.0.0
---

# Builder Phase Workflow

You have been assigned a **full phase** to implement. Your spawn prompt contains the phase file path and plan folder. This skill teaches you how to handle the entire phase end-to-end.

## Why This Workflow Exists

The user experienced builders that guessed at patterns, skipped tests, and produced inconsistent code. Each step below prevents a specific failure:

| Step | Prevents |
|------|----------|
| Read phase completely | Missing requirements, user has to re-explain |
| Pre-flight test check | Cascading failures from broken previous phases |
| Find reference file | Guessing at patterns, code doesn't match codebase |
| Invoke domain skill | Missing project-specific conventions |
| TDD first (Step 0) | Untested code, bugs discovered in production |

## Step 1: Read the Phase

Read the phase file from your spawn prompt. Extract:

- **Prerequisites & Clarifications** — check for unanswered questions first
- **Requirements** (Functional + Technical)
- **Implementation Steps** (Step 0 through Step N)
- **Acceptance Criteria** (your success metrics)

If ANY prerequisite question is unanswered:
```
SendMessage({
  type: "message",
  recipient: "team-lead",
  content: "Phase has unanswered prerequisite questions. Cannot proceed.",
  summary: "Blocked: unanswered prerequisites"
})
```
Then STOP and wait for instructions.

## Step 2: Pre-Flight Test Check

**Skip for Phase 01** — no previous phases exist.

For Phase 02+:

```bash
pnpm test
```

- Exit code 0 → proceed to Step 3
- Exit code ≠ 0 → check if failures are from current phase's TDD (expected) or previous phases
  - Previous phase failures: **fix them first**, re-run to confirm green, then proceed
  - Current phase TDD failures: expected, proceed

**IMPORTANT — "pre-existing" is not an excuse.** After a context compact, you may not know whether failures existed before your work started. It doesn't matter. You own every failure present when you report completion. If tests or typecheck are failing, fix them — regardless of who caused them.

## Step 3: Invoke Domain Skill and Find Reference

Your spawn prompt includes a `Skill:` field (extracted from the phase frontmatter by the orchestrator). If present, use that value. Otherwise, check the phase frontmatter for a `skill` field, or determine from content:

| Phase Focus | Skill | Reference Glob |
|-------------|-------|---------------|
| Database schema, migrations, RLS | `postgres-expert` | `supabase/migrations/*.sql` |
| Server actions, services, API | `server-action-builder` | `app/home/[account]/**/*server-actions*.ts` |
| React forms with validation | `react-form-builder` | `app/home/[account]/**/_components/*.tsx` |
| E2E tests | `playwright-e2e` | `e2e/tests/**/*.spec.ts` |
| React components, pages | `vercel-react-best-practices` | `app/home/[account]/**/_components/*.tsx` |
| UI/UX | `web-design-guidelines` | `app/home/[account]/**/_components/*.tsx` |
| Service layer | `service-builder` | `app/home/[account]/**/*service*.ts` |

1. **Glob** the reference pattern → read ONE file
2. **Extract 3-5 key patterns**: function signatures, imports, naming, error handling, post-operation hooks
3. **Invoke the domain skill**: `Skill({ skill: "skill-name" })`

The reference file is your ground truth. Your code must structurally match it.

## Step 4: Create Internal Task List

Create tasks via `TaskCreate` for each implementation step. **This is not optional** — tasks survive context compacts and are your only recovery mechanism if context is compacted mid-phase. Without them, you must restart the entire phase from scratch.

**Prefix all task subjects with `[Step]`** to distinguish from the orchestrator's phase-level tasks in the shared team task list. Mark each task `in_progress` before starting and `completed` when done.

**Task descriptions must be self-contained:**
- File paths to create/modify
- Function signatures, key parameters
- Which services/actions to call
- Acceptance criteria for that step

Bad: `"Create the dropdown component"`
Good: `"[Step] Create change-role-dropdown.tsx at app/home/[account]/roles/_components/. Props: { membershipId, accountSlug }. Fetch roles via listRolesAction, filter by hierarchy_level. Use @/components/ui Select, Badge."`

**Always start with Step 0: TDD.**

## Step 5: Implement

1. **Step 0 (TDD) first** — write failing tests before implementation code
2. **Remaining steps sequentially** — follow the phase document exactly
3. **After each step**: run `pnpm test`, fix failures before moving on
4. **Mark each task completed** via `TaskUpdate` as you finish it

**Scope boundary — implement ONLY what's in the phase:**
- Do NOT add improvements not specified in the phase
- Do NOT refactor adjacent code
- Do NOT create documentation files

**Key project patterns:**
- Server actions: validate with Zod, verify auth before processing
- Services: `createXxxService(client)` factory wrapping private class, `import 'server-only'`
- Imports: path aliases, ordering: React > third-party > internal > local
- After mutations: `revalidatePath('/home/[account]/...')`

**IMPORTANT:** Before using the Write tool on any existing file, you MUST Read it first or the write will silently fail. Prefer Edit for modifying existing files.

## Step 6: Final Verification

Run the full verification before reporting:

```bash
pnpm test
pnpm run typecheck
```

Both must pass. Fix any failures before proceeding.

### Conditional Testing by Phase Type

The phase's `skill:` frontmatter field determines which additional tests to run:

| Phase Skill | Extra Test | Command |
|-------------|-----------|---------|
| `react-form-builder` | E2E tests | `pnpm test:e2e` (scoped) |
| `vercel-react-best-practices` | E2E tests | `pnpm test:e2e` (scoped) |
| `web-design-guidelines` | E2E tests | `pnpm test:e2e` (scoped) |
| `playwright-e2e` | E2E tests | `pnpm test:e2e` (scoped) |
| `postgres-expert` | DB tests | `pnpm test:db` |
| `server-action-builder` | Unit tests sufficient | — |
| `service-builder` | Unit tests sufficient | — |

**E2E test scoping:**
1. Extract keywords from the phase title/slug (e.g., `notes`, `billing`, `auth`)
2. Glob for `e2e/**/*{keyword}*.spec.ts`
3. If matches found: `pnpm test:e2e -- [matched spec files]`
4. If no matches: `pnpm test:e2e` (full suite)

**Graceful skip:** If a test command doesn't exist (exit code from missing script), skip it and note in your completion report. Projects without E2E or DB tests should not fail verification.

All extra tests must pass before reporting completion.

**Scope boundary:** Your job ends here. Do NOT run `/code-review` — an independent validator teammate will review your work after you report. This separation ensures blind spots are caught by a fresh set of eyes.

## Step 7: Report Completion

Send completion message to the orchestrator:

```
SendMessage({
  type: "message",
  recipient: "team-lead",
  content: "Phase [NN] implementation complete — ready for review.\n\nFiles created/modified:\n- [list]\n\nTests: passing\nTypecheck: passing\n\nAcceptance criteria met:\n- [list key criteria]",
  summary: "Phase NN implemented — ready for review"
})
```

Then go idle. The orchestrator will either assign the next phase or send a shutdown request.

## Resuming After Context Compact

If your context was compacted mid-phase:

1. `TaskList` → find the `in_progress` or first `pending` task
2. `TaskGet` on that task → read the self-contained description
3. Continue from that task — don't restart the phase
4. The task list is your source of truth, not your memory

## Troubleshooting

### Tests fail but code looks correct

**Cause:** Reference patterns may have changed since the phase was written.
**Fix:** Re-read the reference file (Step 3). If the phase's code blocks differ from the current reference, follow the reference — it's the ground truth.

### Domain skill not found

**Cause:** Skill name in phase frontmatter doesn't match available skills.
**Fix:** Check the table in Step 3 for the correct skill name. If the phase focus doesn't match any skill, skip skill invocation and rely on the reference file.