Environment

The world the agent acts on — anything outside the harness that the agent perceives through tool results and changes through tool calls. The harness runs the agent; the environment is what the agent works in. A file like AGENTS.md lives in the environment; the harness is what loads it into the context window. A filesystem is the most common kind of environment, but not the only one (a database, a remote API, a browser session can all be environments).

Avoid: using "environment" for the runtime or the harness itself — the harness is the wrapper, the environment is the workspace.

Usage:

"The agent can't see the staging DB schema."

"Wire it into the environment — give it a psql tool scoped to read-only on staging. The harness is fine, it just has nothing to act on."