Prompt & Done · FANOUT pack
Eight games from one prompt: 45 seconds with one subagent per game.
A subagent is a helper Claude Code starts for one piece of a job. If you ask for one per task and say "all at once", they run at the same time. We gave Claude Code (Sonnet 5.5) the same eight-game job twice, once fanned out and once one after another, and timed both on 22 Oct 2026.
1 The prompt
Make an empty folder, start Claude Code in it, and send:
Build 8 small browser games in games/: snake, pong, breakout, invaders, tetris, asteroids, runner, jumper. Each is one self-contained HTML file with a 360x640 canvas, and opening it with ?demo=1 makes it play itself. Use one subagent per game, all at once.Open any file in games/ in a browser; add ?demo=1 to the address and it plays itself.
2 What we measured
Claude Code 2.1.308, model Sonnet 5.5, one headless run per prompt in an empty folder. Cost is what Claude Code reported (API-equivalent list price; our runs used a subscription).
| Run | Wall clock | API-equivalent cost | Games that loaded and played |
|---|---|---|---|
| Eight subagents, all at once | 0:45 | $0.78 | 8 / 8 |
| One agent, one after another | 2:06 | $0.38 | 8 / 8 |
Fanning out was about 2.8 times faster and cost about twice as much. For comparison, the one-by-one prompt was:
Build 8 small browser games in games/: snake, pong, breakout, invaders, tetris, asteroids, runner, jumper. Each is one self-contained HTML file with a 360x640 canvas, and opening it with ?demo=1 makes it play itself. Build them yourself one after another. Do not use subagents.3 The eight games from the fan-out run
Open each with the demo bot playing:
4 Honest limits
One run per prompt, small single-file games, and times that depend on API load. Fan-out trades tokens for time: it helps when the pieces are independent. It is not a claim about other tasks, other models, or Agent Teams / Agent View, which are different Claude Code features.