How do you coordinate multiple AI assistants on the same web project?

I like a builder-and-reviewer workflow more than trying to make two assistants collaborate directly. One tool creates the implementation, while the other only reviews the diff and reports risks, missing tests, or convention violations. I decide what gets merged. If I want two independent solutions, I put them on separate branches and compare them afterward rather than letting both edit the same files.

A documentation folder and a couple of maintained instruction files make handoffs much smoother. Anything that would otherwise be repeated in multiple chats should be written next to the code, and decisions should not be considered final until the documentation is updated. The important part is reviewing those files regularly; stale instructions can cause both assistants to keep making the same wrong assumptions.

Routing by strengths can work well: use a quick model for autocomplete, small syntax questions, and routine edits, then use a stronger reasoning model for architecture, database design, complicated debugging, and refactoring reviews. The exact model rankings change over time, so I would test them on your own codebase instead of relying on a universal list. Clear project instructions matter more than the model choice when the task is complex.

The easiest solution is to create a shared source of truth inside the repository. Keep a concise project guide with the architecture, coding conventions, important decisions, constraints, and current status. Put each task's scope and acceptance criteria in an issue or task file too. Then one assistant can implement the change on a branch, while the other reviews the diff against those written requirements. If they disagree, let tests and reproducible behavior decide instead of having them debate in chat.