Filesystem

A tree of files and directories the agent reads from, writes to, and executes within — the default kind of environment for a coding agent. AGENTS.md, skills, source code, build scripts, and tool configs all live in a filesystem. When a harness "starts in your project," it's pointing the agent at a filesystem.

Usage:

"Why isn't it picking up my AGENTS.md?"

"It's running against a different filesystem — the sandbox mounted the parent dir, not the project root. Repoint the harness."