Step 5 — The Code (Where AI Shines)
Multiple AI programmers work in parallel, each on a different file. The team lead splits work so they never collide.
Now the magic.
We can't have one programmer write everything serially — that takes too long. So we run 3 to 5 AI programmers in parallel.
The trick: each programmer gets different files. They never edit the same thing. No collisions.
File ownership
Before any code starts, the team lead writes a file ownership table. This is the assignment list — who works on what.
Programmer 1: src/core/InputManager.js src/core/PhysicsEngine.js
Programmer 2: src/scenes/GameScene.js src/scenes/BossScene.js
Programmer 3: src/scenes/MenuScene.js src/scenes/ResultScene.js
Programmer 4: src/audio/SoundManager.js src/audio/MusicLoop.js
✓ No two programmers edit the same file. ✓ 4 hours of work in 1 hour.
/parallel
4 programmers, 1 hour. Same as 4 hours alone.
Splitting work by file is the simplest rule that keeps everyone moving without stepping on each other.
The team lead writes the assignment list before any programmer starts. After that, it's locked.
How they coordinate
Every programmer posts updates on a shared task card. Like a group chat for the work. Visible to me, visible to other agents.
10:42 Programmer 3 done. ✓ menus, results ✓ 12 unit tests pass 10:51 Programmer 1 done. ✓ physics, taps 10:58 Programmer 2 done. ✓ scenes, bosses 11:03 Programmer 4 done. ✓ audio, music loop
✓ All four finished in ~1h.
/visibility
Every step is visible.
The card shows who started, who finished, what they did. No "I'm still working on it" — the work shows up as it's done.
If a programmer gets stuck, you see it within minutes and reassign or unblock.
What each programmer must produce
Every programmer follows the same checklist before they're "done." This is non-negotiable.
✓ Code matches the plan rules ✓ Unit tests written for new logic ✓ Tests pass locally ✓ No console errors at runtime ✓ Only assigned files touched ✓ Commits are atomic + descriptive
# Comment on Trello with:
- which plan rules I covered
- which files I changed
- test output (paste the real result)
- commit hash
# If any check fails, comment # "blocked" + reason. Don't fake.
/done
"Done" has a definition.
Without this checklist, "done" means whatever the programmer feels. With it, "done" is a verifiable list.
Reviewer (next phase) reads this comment and re-runs the test commands. If they don't pass, the work goes back.
When two programmers need the same file
Sometimes a feature genuinely needs both GameScene.js and InputManager.js. We solve this by splitting the work in time, not parallel.
✗ Programmer 1: edit GameScene + Input ✗ Programmer 2: edit GameScene + Audio → both touch GameScene.js → merge conflict
# Right — sequence one through
✓ Programmer 1: GameScene + Input → commits, marks done ✓ Programmer 2: GameScene + Audio → starts AFTER Programmer 1 done → pulls latest, edits cleanly
# Slower, but no conflicts.
/serial
When in doubt, sequence it.
Parallel speed isn't worth the merge nightmare. If two programmers genuinely need the same file, run them one after the other.
The team lead decides this before either programmer starts. No mid-flight scrambling.
Real example — BOP code in 1 hour
10:00 All 4 programmers start
10:42 Menus + Results — done 10:51 Physics + Input — done 10:58 Scenes + Bosses — done 11:03 Audio — done
11:05 Reviewer starts 11:18 Reviewer approves
11:18 Tester runs all UC playthroughs 11:31 9 of 9 PASS
11:31 Release builds + deploys 11:44 Live on staging
✓ 1h 44m: idea to staging
/case-study
BOP: 1h 44m from "go" to staging.
That's the actual timestamp from our Trello card. Not a marketing number.
The 1h 44m doesn't include earlier idea/discussion/plan/design steps — those took the morning. Code phase alone was 1 hour.
Common pitfalls
✗ Skipping file ownership ("we'll figure it out")
✗ Programmer adds a feature outside the plan
✗ Programmer claims "done" without running tests
✗ Two programmers blocked, both waiting for each other
The team lead's job is to catch these in 5 minutes, not 5 hours. The Trello comments make it visible.
What you can copy
Even if you have just 1-2 AI sessions:
- Write the file map first. Even for 1 programmer.
- Define "done" in writing. Use the checklist.
- Make every programmer post comments. Visibility is everything.
- Sequence, don't fight, when files overlap.
Parallel without chaos = pipeline with leverage.