Here is how I tested 43 files in about an hour.

The agent

An agent is a prompt with its own context window. Each one tackles its assigned task, handles the nuances, and keeps you in the loop.

Test the prompt on a single file first. A QA engineer prompt:

Be a QA Engineer.

Analyze the given file, understand the purpose of the class, and write a unit test in <folder>.

Use a black box strategy: pass inputs, assert outputs. Don’t mock anything without planning it with me first.

Once it works, save it with /agents as “qa-engineer”.

The coordinator

Then create a coordinator that spawns agents in parallel:

Be an AI Agents Coordinator.

Unit test all of these files:

file1.ts file2.ts

Spawn one qa-engineer agent per file. All unit tests go in ./tests/.

Results: 43 files, about an hour, 100 dollars on Opus 4.5.

Each agent has its own 200k token context window. Understand your usage before going wide.