Three people on the team, three agents, one shared codebase. Monday morning you open it: everything runs, tests are green. But read closely and it reads like three strangers wrote it — one naming style here, one error-handling style there, an entirely different structure over there.
And it is three strangers, really. Not your three teammates — they understand each other. Three agents, each running on the rules sitting in its own owner's head. And those three heads have never once sat down and agreed on anything.
01Solo advice cracks at team scale
Almost all the wisdom about working with an agent — including most of this garden — quietly pictures one scene: you, one agent, one task. You learn to instruct it, to set gates, to manage it. All of it is right. And all of it lives in your head.
That "lives in your head" is exactly where it cracks. When it's just you, one set of conventions in your head is enough — you're the only one giving orders, so your agent is consistent with you. Add a second person with their agent, and suddenly there are two sets of conventions in two heads, neither knowing the other. Each agent is still consistent — with its owner. But the shared thing, the one all of them touch, starts pulling in three directions.
Here's the turn: at team scale, the question is no longer "is my agent doing well." It's "are the team's agents pulling the same way." An agent twice as good that pulls against the other two just makes the shared thing tangled twice as fast.
✕ Rules in each person's head
✓ Rules live in the shared place
The difference isn't "a more disciplined team." It's that the rules change their address: from inside each head — where no one else can read them — to one shared place every agent can reach.
02Three problems that only appear with a team
Going from one person to a team, three new things grow. They aren't harder versions of old problems — they're new problems, existing only when there are many people plus many agents.
Each agent runs on the rules in its owner's head. With no shared written rulebook, three agents will name differently, handle errors differently, structure differently — and the shared thing cracks along each seam.
"The agent wrote it" is not an excuse. When half the changes are agent-generated, it must be clear who puts their name on each part — because the agent can't be accountable.
A skilled agent user knows what to delegate, where to gate — but that knowing lives in the craft, unspoken. A new teammate can't inherit it, unless it's pulled out into something teachable.
Three problems, one shared root: what was enough inside one head — conventions, ownership, craft — now has to be pulled out and made shareable. A team doesn't fail for lack of skilled people; it fails because the skill doesn't transfer between them.
03Pull the rules out of the head, into the shared place
The thread that fixes all three is one: anything that used to live in one head but the whole team now needs must be written down and put in a shared place. Not because writing is fancier — because a head doesn't replicate, but a file every agent can read does.
Diverging conventions are fixed by one shared rulebook, sitting with the work, that everyone's agent loads. Blurred ownership is fixed by a clear habit: the person who hits merge owns it, and "the agent wrote it" doesn't lift that. Tacit knowledge is fixed by turning the craft into something teachable — a path a new teammate can follow, instead of re-fumbling what you already fumbled.
This is also where the Tools & setup cluster grows a level: there, CLAUDE.md is the operating law for your agent; here, it becomes the operating law for the whole team's agents — same idea, but now it has to live in the shared place, get reviewed like code, and be clear enough that someone who never sat beside you can still follow it.
04One person's skill doesn't become a team's skill on its own
One person who's brilliant with an agent doesn't automatically make the team brilliant too. That brilliance, while it stays in their head, is one person's asset — and it evaporates on exactly the day they take leave, or when a fourth person joins and no one passed it on.
Hold one line: when the whole team has agents, the thing that must be consistent isn't the people — it's the rules they all feed their agents. People each have their own style, and that's fine. But the shared thing all three agents touch must pull one way — and that direction only exists when it's written in one place, not scattered across three heads that have never spoken.
Three faces of teamwork with agents, one piece each: one rulebook for every agent · who owns what the agent wrote · bringing a new teammate up to speed.