Implementation Execution Workflow

You are starting the WORK phase of compound engineering. Your goal is to execute the implementation plan systematically with quality built in.

Prerequisites

Before starting work:

1. Ensure a plan exists (from /workflows:plan) or create one inline
2. Understand the platform(s) involved
3. Set up MCP tool sessions as needed

Step 1: Load the Plan

If a plan exists:

Read: plans/[plan-name].md

If no plan exists, create a quick inline plan before proceeding.

Step 2: Create Task List

Use TodoWrite to track implementation progress:

TodoWrite: Create tasks from the plan's implementation steps

Mark tasks as in_progress as you work on them and completed when done.

Step 3: Follow the TDD Loop

For every feature, follow this cycle:

1. Write a failing test
2. Write just enough code to make it pass
3. Refactor if needed
4. Repeat until feature is complete

This is non-negotiable. Tests come FIRST, then implementation.

Step 4: Platform-Specific Execution

iOS Execution

1. Set up Xcode session:

mcp__xcodebuildmcp__session-set-defaults(
  projectPath: "apps/mobile/Mellow.xcodeproj",
  scheme: "Mellow",
  simulatorName: "iPhone 16 Pro"
)

2. For each implementation task (TDD cycle):

a) Write a failing test FIRST:

• Test file mirrors implementation file path
• Use Swift Testing framework (@Test, #expect)
• Mock all external dependencies
• Run test to confirm it fails: mcp__xcodebuildmcp__test_sim

b) Write just enough code to pass:

• Follow the architecture pattern:
  • Screens go in Features/[FeatureName]/Screen/
  • Views go in Features/[FeatureName]/Views/
  • ViewData/ViewActions go in Features/[FeatureName]/ViewData/
  • ViewModels go in Features/[FeatureName]/ViewModel/
• Run test to confirm it passes: mcp__xcodebuildmcp__test_sim

c) Use MellowDesignSystem:

// Colors
Color.mellow(.textPrimary)
Color.mellow(.appBackground)
Color.mellow(.accent)

// Typography
.mellowTitle(.m)
.mellowBody(.m)
.mellowLabel(.s)

// Spacing
MellowSpacing.m  // 16pt
MellowSpacing.l  // 24pt

// Buttons
.mellowPrimaryButton()
.mellowSecondaryButton()

d) Refactor if needed, then repeat the cycle.

3. Build verification:

mcp__xcodebuildmcp__build_sim

4. Run tests:

mcp__xcodebuildmcp__test_sim

5. Visual verification (if UI changes):

mcp__xcodebuildmcp__build_run_sim
mcp__xcodebuildmcp__screenshot

6. UI automation (if testing interactions):

mcp__xcodebuildmcp__describe_ui  # Get element coordinates
mcp__xcodebuildmcp__tap(x: ..., y: ...)

TypeScript Execution

1. For each implementation task (TDD cycle):

a) Write a failing test FIRST:

• Use Vitest for testing
• Mock external dependencies
• Run to confirm failure: pnpm test --filter=@mellow/[app-name]

b) Write just enough code to pass:

• Use Zod for validation
• Follow Fastify route conventions
• Use existing middleware patterns
• Run test to confirm it passes

c) Example Fastify route:

import { z } from 'zod'

const bodySchema = z.object({
  name: z.string().min(1),
})

export async function routes(fastify: FastifyInstance) {
  fastify.post('/resource', {
    schema: {
      body: zodToJsonSchema(bodySchema),
    },
  }, async (request, reply) => {
    const body = bodySchema.parse(request.body)
    // Implementation
  })
}

d) Refactor if needed, then repeat the cycle.

2. Type checking:

pnpm type-check --filter=@mellow/[app-name]

3. Linting:

pnpm lint --filter=@mellow/[app-name]

4. Run tests:

pnpm test --filter=@mellow/[app-name]

5. For web features, use Playwright:

mcp__plugin_playwright_playwright__browser_navigate(url: "http://localhost:3000/...")
mcp__plugin_playwright_playwright__browser_snapshot

Database Execution

1. Check current schema:

mcp__plugin_supabase_supabase__list_tables(project_id: "...", schemas: ["public"])

2. Create migration:

mcp__plugin_supabase_supabase__apply_migration(
  project_id: "...",
  name: "add_feature_table",
  query: "CREATE TABLE ..."
)

3. Always include RLS policies:

-- Enable RLS
ALTER TABLE feature_table ENABLE ROW LEVEL SECURITY;

-- User isolation policy
CREATE POLICY "Users can only access own data"
  ON feature_table
  FOR ALL
  USING (user_id = auth.uid());

4. Validate with advisors:

mcp__plugin_supabase_supabase__get_advisors(project_id: "...", type: "security")
mcp__plugin_supabase_supabase__get_advisors(project_id: "...", type: "performance")

5. Generate types:

pnpm types:generate

Step 5: MANDATORY Quality Gate (NON-SKIPPABLE)

CRITICAL: This step MUST be run after EVERY implementation chunk, not just at the end.

Run Quality Gate Skill

Use the quality-gate skill for all verification:

Changed Files	Skill Section
*.ts, *.tsx	skills/quality-gate.md#typescript
*.swift	skills/quality-gate.md#ios
*.sql, supabase/**	skills/quality-gate.md#database

Run all applicable checks IN PARALLEL.

Requirements

• ALL checks must pass
• Do NOT skip any failing check
• Do NOT proceed to commit with failures
• Fix issues immediately, then re-run ALL checks

See skills/quality-gate.md for:

• Exact commands to run
• Output format
• Failure handling

Step 6: Commit (ONLY after Quality Gate passes)

CRITICAL: You may ONLY commit after ALL checks in Step 5 pass.

1. Verify Quality Gate passed:

   • All lint checks green
   • All type checks green
   • All tests green
   • Build successful

2. Commit changes:

   git add -A
   git commit -m "feat: [description]
   
   - [change 1]
   - [change 2]"
   

3. Update task list: Mark all completed tasks as done.

4. Suggest next step: Recommend running /workflows:review to validate the implementation.

Important Notes

• Never commit with failing checks. Fix issues first, re-run checks, then commit.
• Follow the plan. If you need to deviate, update the plan first.
• Test continuously, not just at the end.
• Use MCP tools for verification rather than relying on assumptions.
• Mark todos as complete as you finish each task.
• Don't ship incomplete work. Finish each phase before moving on.

Skills Used

• quality-gate - Verification commands (Step 5)
• ios-ui-automation - iOS simulator interactions
• web-ui-automation - Playwright interactions
• git-workflow - Commit conventions (Step 6)