If the operating truth of a company disappears when a session ends, the next session starts by reconstructing the company. Casa makes the truth a set of files that outlive every session and every harness.
Four files, one company
The brain is deliberately small. profile.md holds identity: what the company is, who it serves, what it will not do. state.md holds the current level, phase, and open threads. ledger.jsonl is append-only memory: every decision, dated, never edited in place. NOW.md is a derived view, recomputed each session, that answers one question: what matters right now.
Plain text is a feature, not a compromise. A founder can read every file without Casa. Git gives history, diff, review, and backup for free. And any agent that can read files can operate the company.
Derived, never hand-edited
State transitions go through the engine, and the readable view is recomputed from the record. Nobody, human or model, edits the summary into a new reality. If the summary is wrong, the record that produced it is inspectable, which is the difference between a dashboard and a story.
The same discipline applies to levels. A company moves from level 0 to level 1 because the gates for level 1 passed, and the ledger shows when and why. Progress claims trace back to entries.
The ledger is the memory. The view is derived. Nothing is edited into truth.
Switching harnesses is a non-event
Because the brain is files in your repository, moving from Claude Code to Codex, or to whatever ships next year, changes nothing about the company. Clone the repo, open the new harness, run the next session. The record does not care which model reads it.
This is the anti-lock-in argument in one line: the company is yours because the files are yours. Casa can be forked, the brain can be read without Casa, and no hosted service sits between a founder and their own operating record.