Environment
Where tool calls run, and the lifecycle Brain drives.
An environment is somewhere tool calls actually execute. Brain drives its lifecycle over the
environment/v1 HTTP contract:
setup · attach · call · execute · cancel · detach · teardown
The adapter implements them. Brain decides when they happen.
Addressed by object, not by connection
The exact Environment object used by tool().useIn(environment) identifies one logical attachment.
Several Tools using the same object share it; calling the factory again creates another attachment.
The generated private identity resolves to provider state rather than whichever process happens to
hold a socket.
Connections are caches. They never decide identity, and they never decide teardown.
Replay is explicit
Every operation carries a stable identifier and the identity of its request. When a redelivery arrives, the adapter can tell "this is the same call again" from "this is a new call that looks similar", and Brain never replays an ambiguous effect against a replacement target.
The official adapters
@aexhq/env-app is a language-neutral HTTP environment — bring your own runtime.
@aexhq/env-aws-microvm runs tools in an AWS MicroVM.
Both use the public contract, so a third-party adapter is not a second-class one. See Write an environment.