An Agent Without an Isolated Environment Hands You a Guess

How much an agent can finish on its own depends on whether it can run what it just wrote and look at the result.

With somewhere to run, an agent finds its own mistakes

Give an agent an isolated environment of its own and it writes the change, starts the product, opens the page, sees the headline hasn't moved, fixes it and looks again. Over and over, before you see anything.

What reaches you is often a second or third draft, with most of the obvious mistakes already out of it, because the agent checked its own work before handing it over.

With nowhere to run, it hands the job to you

An agent that can't run its work is guessing. It hands you the guess, and then somebody has to open a browser and check it.

Which makes you the slowest part of your own setup. Not because you're reviewing too much, but because you're doing the agent's first pass for it.

One environment each, not one shared

Two agents working in the same environment can overwrite each other's changes, and then neither result tells you much.

The isolation is what makes the result readable. An agent that runs its change somewhere nothing else is touching can trust what it sees, and so can you.