(Method) — Plan → Direct → Check → Correct → Ship
Hyunjun Kim
Method
Spec-First Solo Build
How I take a product to launch by setting the bar and directing AI — without writing the code myself
This page distills the working rules I've actually followed into one method. It's not marketing copy — it's the procedure I repeat on every project. The templates below are public skeletons. Per-project real excerpts live in each case study under "Directing AI."
(01)
Framework: 7 steps from zero to launch
Fig. ai-workflow-01
Plan to ship — the direct · check · correct loop
Off the bar → point at the cause, re-direct · repeat
- 01
Set the rules and design in docs first
Since I don't read the code directly, the first line of defense for quality is a rules document. Per project I pin my way of working, the don'ts, and the verification bar in a rules document, then have each session read it and sync with "tell me the current stage."
- 02
Pull all the design/UI and data first, then build
Doing both at once gets tangled, so I lock screens and data first. (e.g., export all screens in a design tool, then wire them in code.)
- 03
Instruct in small pieces and verify by running it myself
Not "it's done" — I run it on a phone/simulator and confirm **with my own eyes**.
- 04
Give the bar and benchmarks in words, not scores
I specify quality by reference (big-company apps) and tone, and delegate the implementation.
- 05
Catch what's wrong and change direction
I distrust plausible success ("this isn't hardcoded, right?") and, when stuck, pivot immediately to what works (no fakes, pragmatic pivots).
- 06
Don't trust AI's self-report — verify with evidence
I re-confirm with the actual code, artifacts, or different inputs, not "memory."
- 07
Keep context in handover docs and run multiple AIs like a team
I document context so it survives account/context changes, and for multi-session work I appoint one session as PM.
Spec-First Solo Build — write the rules and the bar first, then direct AI to build, check, and correct until it ships.
Steps 3–6 aren't one-and-done — I loop instruct → check → correct.
(02)
Principles
- 01
Don't guess
If one fix fails, search official docs/similar cases before the second attempt.
- 02
Show before building
New screens/structures are reviewed as mockups or designs first, then built.
- 03
State the impact before changing
Explain side effects and knock-on issues first; change only after approval.
- 04
Verify the value flows end to end
Adding a field/parameter means fixing every call site, not just the definition, and re-reading the generated code before submitting.
- 05
For "can't be wrong" areas, write the bar down
Where mistakes are fatal (security, payroll), the design doc comes before code.
- 06
Turn failure into a principle
From one loss or incident, extract one rule that prevents a repeat. (The "approve before changing" rule came from an early trading-bot failure.)
- 07
Keep docs and code in sync
Every release, I check the figures in the docs against the actual code. AI-written docs drift easily, so I make the cross-check a habit.
(03)
Prompt Templates (skeletons)
I share only the skeletons of the instructions I reuse. The detailed conditions, ordering, and acceptance criteria that actually made them work are shared in interviews/collaboration. Short per-project excerpts (1–2 sentences) live in each project's case study under "Directing AI."
A. Idea evaluation — no arbitrary scores; grounded in real cases
Redefine the problem → search similar cases → compare success/failure patterns
→ evidence-based scorecard → derive ideas → summary (top + risks + next action)
[per-step criteria, counts, and pass/fail rules are kept private]
B. Feature instruction
[Goal] … [Bar] behaves like this / not this [Constraints] stack & policy (checked in docs) [Check] what I'll inspect
C. Bug-fix instruction
[Symptom] … [First] cause first — search & hypothesis [Before fixing] explain impact → change after approval
(04)
How I Catch Errors
- 01
State the symptom as fact
I tell AI what happened, when, and on which screen, reproducibly.
- 02
Cause first, no guessing
I search official docs/similar cases and form a cause hypothesis.
- 03
If the first fix misses, stop
I search again before the second attempt — I don't repeat the same guess.
- 04
Verify the value flows end to end
After fixing, I re-read every call site and the generated code.
- 05
Leave a rule that prevents a repeat
I record it as a working principle or design bar.
Real debugging cases (symptom → instruction → failure → fix) live in each project's "How I Fixed It".
(05)
Mistakes → Lessons
Mistake
Over-trusting a trading bot → a loss
✓ Lesson
explain impact and get approval before changing (still applied on every project).
Mistake
AttenNFC: AI-generated code below the bar
(only 5 of 9 payroll variables, API mismatch, hardcoded GPS).
✓ Lesson
verify AI output against the bar and, when it diverges, instruct a rewrite. After the rewrite I confirmed `flutter analyze` reported zero issues.
Mistake
MECHOOSE: early screen structure packed into one file
✓ Lesson
set the separation bar at the start — it makes later changes cheaper.
(06)
The work in numbers (approximate)
- 149 claude.ai conversations · ~9,002 user instructions (Feb–Oct 2026, ~8.5 months) — total activity, including personal and non-portfolio chats.
- Five products reached a launch/deploy stage (THE HOUSE, MECHOOSE, Momento, Money Navigation, MemoHub); two running live (MECHOOSE, MemoHub).
- Most instructions in a single conversation: THE HOUSE, 696.
Figures are record-based approximations (per-project classification of chats is a title/keyword heuristic, so estimated).
(07) Honest
Honest Review
If a developer had built it — strong · on par · next step
- THE HOUSE
Strong3On par4Next step5
↗ Testing & automation — no automated tests or CI yet
Plan → Tests + CI for purchases and saves, module split, private Git, server-side purchase checks before public launch
- MECHOOSE
Strong3On par4Next step4
↗ Testing & automation — no tests, CI, lint, or type checks yet
Plan → Tests + CI on payments first, split the backend by domain, move orders and payments to proper tables, add error alerting
- Momento
Strong3On par4Next step5
↗ Testing & automation — only the matching engine has tests
Plan → Pin the live schema in the repo, add core-flow tests and CI, server-side purchase checks, Android parity
- AttenNFC
Strong2On par3Next step4
↗ Feature completeness — implementation ~10–15% of the design
Plan → Finish one verified check-in round trip end to end, then tests/CI, translations, and labels as screens are built
- AI Video Streaming Platform
Strong4On par3Next step3
↗ Testing & version control — no tests, no git
Plan → Private Git and payment tests first, then CI, monitoring, backups, and rollback
Per-project verdicts live in each case study.
(08) Skills
Capabilities
Tap a skill to filter the projects
AI Agents & Models01
Design02
Mobile03
Build & Ship06
Backend & Infra07
- Supabase (Postgres · RLS · Edge Functions)04
- Cloudflare Workers / D1 / R2 / Workers AI
- Deno · Hono01
- Firebase Cloud Messaging (push)01
- Payments: Omise · in-app purchases (StoreKit, Play Billing, Unity IAP)03
- LINE Login · Google Maps Platform02
- AdMob01
- Python · Telegram Bot API · Google Cloud Run · Docker01
Analytics, Marketing & Collaboration08
- Google Analytics 401
- Rule docs & handover docs that steer AI sessions04
- Google Ads · Meta Ads
- Notion · Slack
Video & Content09
- Google Flow (Veo 3.1) — AI short drama
- CapCut (editing)
- Kling (AI video, tried)
- X / Threads post automation (game marketing)01
- Hailuo (AI video)