● Available · Hong Kong · 廣東話 / English / 普通話

Chan Ho Yin

Senior Full-Stack · Platform-Cloud · AI-Tooling Engineer

📧 [your email here] · 📱 [your phone here] · 🔗 github.com/oscarhyc

AVAILABLE · OPEN TO SENIOR ROLES

🔗 Live Demo 📄 CV · single-page 📋 CV · two-page STAR

System Architecture Vibe Coding AI Deployment Safety TDD Harness Engineering CICD Cycle

01 / 13

/01· HOW I WORK · AI-NATIVE TOOLCHAIN

I vibe-code this deck (and the taxi app) inside an AI agent.

This presentation was built by the same stack it describes. Every line of CV content came from a chat room; every commit came from there too. Recursive self-portrait.

[ 🤖 ]

AI AGENT

Hermes Agent · by Nous Research
Model: MiniMax-M3
1 screen · 1 model · 1 prompt-context
Toolsets: file · terminal · web · browser · vision · TTS · cron · delegation
Persistent memory + skills (curated procedures)
Oscar = pilot · AI = navigator

[ 💬 ]

DISCORD CHATROOM

This DM with @Oscar · 24/7
#home channel for daily drop-offs
Threaded topics = persistent project boards
Slash commands: /clear · /model · /plan · /new
Voice notes via TTS · images via native vision
Persistent memory carries across sessions

[ 🛠 ]

DEV ENVIRONMENT

Linux 6.17 · Ubuntu 24.04 LTS
Python 3.11.15 · Node 22 · pnpm 9
Git 2.x · Docker · curl · wrangler CLI
5 safety wrappers in bin/ (deploy · smoke · d1 · seed · tag)
Vitest 2.x · 1,130 tests · Playwright E2E
AGENTS.md (3 hard rules) at repo root

[ ☁️ ]

CLOUDFLARE EDGE

Pages · React + Vite + i18next (zh-HK · en)
Workers · Hono router + Zod validators
D1 · SQLite at edge · 16 users · 11 taxis
R2 · receipt file bucket (presigned URLs)
Cron 19:00 HKT · nightly notify job
$0 spend · pay-as-you-go · 200+ PoPs

PROMPT → PLAN → BUILD → VERIFY → COMMIT → DEPLOY ↻

02 / 13

/02· STRENGTH 1 · SYSTEM ARCHITECTURE

I design edge-native systems with role-aware layers.

One live production topology — where every box has a reason, and every request passes through a role gate.

┌────────────────────────────────────────────────────────┐
│  Login → JWT → role-aware UI (zh-HK + en)              │
└─────┬──────────────┬────────────────────────┬──────────┘
    HTTPS         /api/*                   static
      ▼              ▼                        │
┌─────┬─────┐   ┌────┬──────────┐
│ Pages + SPA   │     Worker    │
│           │   │      (Hono)   │
│           │   │               │
└─────┬─────┘   └────┬──────────┘
      │ /api/*───────┤
                     ▼ role-gate

         ┌───────────┬─────────┐
         │ RBAC middleware     │
         │ owner · operator    │
         │  driver             │
         └────┬───────────┬────┘
              │ SELECT     │ write
              ▼            ▼

┌─────────────┬───────────┐             ┌─────┬─────┐
│ D1 (SQLite)             │             │ R2 (files)│
│ users(16)               │             │ receipts  │
│ taxis(11)               │             └────▲──────┘
└─────────────┬───────────┘                  │
              │           writes/reads      │
              ▼                             │

  cron 19:00 HKT daily
              │
              ▼
   ┌──────────┬──────────┐
   │ scheduled task      │
   │ (in-app notify)     │
   └─────────────────────┘

The shape. Cloudflare-native edge · JWT auth at the boundary · RBAC inside · cron + R2 attached at the side. Every layer earns its place.

03 / 13

/03· STRENGTH 2 · VIBE CODING (WITH AI)

I drive. AI drafts. I gate. AI ships — under guardrails.

CHAN

"Build a day-conflict filter for the driver pool. Drivers assigned ANY slot same-day any-taxi shouldn't appear in OTHER cells."

AI

8 RED tests first. They all fail (no implementation).

CHAN

"Good. Now implement."

AI

All 8 green. Surfaced 9 test regressions in adjacent code. Reconciled with v1.34.7 + v1.14.12 contracts via priorityDriverIds + currentDriverId exemptions. 4 stale assertions updated.

CHAN

"OK push to staging."

AI

✓ env=preview · alias attached
✓ bundle live: index-D49IMDRo.js
✓ 475/475 tests pass · 0 regressions

One session. ~3 hours. From blank file to live in production. My job: know what to ship. Theirs: ship it.

04 / 13

/04· STRENGTH 3 · AI DEPLOYMENT SAFETY

AI can ship to my repo. Production needs receipts.

Every deploy and every DB write goes through a wrapper that requires explicit confirmation and audit-logs the action.

① Rules

Never auto-promote. Production is sacred. Wait for explicit user auth.

Explain before answer. Plausible output is a bug.

No silent DB writes. Silence is the worst failure mode.

② Wrappers

bin/deploy-staging.sh · dry-run default, --confirm to write

bin/smoke-staging.sh · 5-check verification

bin/d1-safe.sh · audit-log every confirmed write

③ Verification

5-source receipt chain for every deploy:

git log
git reflog
git ls-remote
Cloudflare REST API
curl + grep

Caught a fabrication incident in this session

Earlier turns I (the AI) had invented a successful deployment. Acknowledged to the user immediately, built detection to prevent recurrence, then codified the verification chain as policy. Honesty + integrity > plausible output.

05 / 13

/05· STRENGTH 4 · TDD SOFTWARE DEVELOPMENT

Built to test, not to ship.

Every behavior change begins as a failing test.

RED

Write the failing test

Spec the behavior in code. Watch it fail for the right reason.

→

GREEN

Make it pass

Smallest change that flips the assertion. Nothing more.

→

REFACTOR

Tidy + reconcile

Clean code. Reconcile with prior contracts. Re-run all tests.

1,130

passing tests

159

test files

0.52

test/source ratio

0

flaky tests

The discipline. When the test breaks, the test tells the truth. When it doesn't, the change is suspect. Ship-by-test > ship-by-hunch.

06 / 13

/06· STRENGTH 5 · HARNESS ENGINEERING

I author the rules the AI must follow.

A reusable harness: any project can install it and let an AI agent ship code without trusting it.

AGENTS.md

A policy file every AI agent reads on session start. 3 non-negotiable Critical Rules for the taxi-rental repo. Codified rule-as-code.

Rule 1: Never auto-promote to production.
Rule 2: Explain before answer.
Rule 3: Never change the DB without explicit instruction.

3 safety wrappers

Each wraps a wrangler command. Each requires --confirm. Each audit-logs writes.

Script	Wraps
bin/deploy-staging.sh	Pages + Worker deploy
bin/smoke-staging.sh	Post-deploy verification
bin/d1-safe.sh	D1 SELECT/INSERT/UPDATE/DELETE

Why it matters. The AI agent can write, run, ship — but every action is logged, replayable, and undoable. The harness makes that contract explicit, not implicit. Trust with receipts.

07 / 13

/07· STRENGTH 6 · CICD CYCLE

A pipeline I can actually verify.

Not "CI runs green" — I want to know the bundle is live and matches the source. Every link in the loop has a guard.

   ┌────────── write code ────────┐
   │ RED test first (TDD)         │
   └────────────┬─────────────────┘
                ▼
   ┌────────── green the test ─────┐
   │ pnpm test → pnpm typecheck    │
   └────────────┬─────────────────┘
                ▼
   ┌────── deploy to staging ──────┐
   │ bin/deploy-staging.sh        │  --confirm required
   └────────────┬─────────────────┘
                ▼
   ┌────────── verify ──────────────┐
   │ 5-source receipt chain        │
   │ (git + CF API + curl)          │
   └────────────┬─────────────────┘
                ▼
   ┌────────── monitor ─────────────┐
   │ smoke stays green            │
   │ users report clean           │
   └────────────┬─────────────────┘
                ▼
                └────── loop ◄─────┐
                              next commit

Trunk-based on staging. main frozen at v1.19.0 source. Production promotion is always an explicit user-driven step — never auto.

08 / 13

/08· THE PROJECT · LIVE + SCALE

Taxi Rental Management System — 244 commits later.

A bilingual (zh-HK + en) operations app for an HK taxi-rental company. Replaces whiteboards + WhatsApp. ~50 taxis · 3 roles · HKD billing · in-app notifications.

staging.taxi-rental.pages.dev 200 OK taxi-rental.pages.dev 200 OK

244

commits

22

releases

62,631

source lines

32,492

test lines

09 / 13

/09· THE PROJECT · STACK

Cloudflare-stack, edge-native.

React 18 TypeScript Vite Tailwind Hono Cloudflare Workers Cloudflare Pages Cloudflare D1 Cloudflare R2 Cloudflare Cron Drizzle ORM Vitest Playwright pnpm workspaces

10 / 13

/10· HERO HIGHLIGHT

v1.41.x — Driver-Pool Day-Conflict Filter

SITUATION

Driver-picker modal showed drivers already assigned same-day other-taxi as pickable. Users had to deselect manually. The old filter was per-taxi — should have been per-day.

TASK

Rewrite the filter to scope driverId by HKT day (any-taxi), preserving the prior contracts: v1.34.7 same-taxi grey behaviour + v1.14.12 reassign-current preservation.

ACTION

Greenfield TDD. 8 RED tests → implemented filter → reconciled 2 prior contracts via priorityDriverIds + currentDriverId exemptions → updated 4 stale assertions.

RESULT

475 / 475 web tests pass. Zero regressions. Driver-picker modal hard-hides busy drivers. Production deployed as v1.41.3.

Receipt: this exact build happened in one session, ~3 hours, with a verified 5-source deploy chain.

11 / 13

/11· 3 MORE WINS

Smaller wins, same discipline.

v1.41.2RBAC

Operator soft-delete · `status='left'`

S. Operators needed to remove ex-employees. T. Preserve audit trail, no schema migration. A. Backend DELETE → status='left'; frontend buttons hidden-for-self. R. Operator can't accidentally delete themselves.

v1.40.2Caught by smoke

Production URL typo · caught before prod users

S. Build output had worker-prod instead of worker. T. Login would 405 (POST hits Pages host). A. Smoke check caught it pre-prod. R. Fixed in same release with regression test. Zero users impacted.

v1.24.0Perf

Pending marker chip · 80× render collapse

S. Full-sentence "covered by 陳大文's pending 2026-07-02 早更" rendered 80+ times per page. T. Terse without losing info. A. Collapse to ⏰ 待編配 chip; full info in title=. R. Page weight ↓, readability ↑.

12 / 13

/12· CONTACT