One branch at a time
The workspace shows one branch and can switch; the branch is part of every document's address in the API, the URL, MCP tool inputs and the change feed. A hosted project's default branch comes from GitHub and follows it. Any other branch is indexed whole the first time it is opened, read again whole after a force-push, and leaves the index when it is deleted on GitHub.
Merges, not locks
A write carries the hash of the version you loaded. If the file changed underneath you, the edits are three-way merged against that version: frontmatter key by key, the body line by line.
sequenceDiagram participant A as ada participant N as notdocs participant C as claude-code A->>N: docs.get pricing.md (hash h1) C->>N: docs.get pricing.md (hash h1) C->>N: docs.update baseHash h1, adds a paragraph N-->>C: ok, hash h2 A->>N: docs.update baseHash h1, rewords a sentence N->>N: three-way merge h1 → h2 + ada's change N-->>A: ok, merged, hash h3
A real conflict, two edits to the same lines, is not written. It comes back as a diff with a recommendation: keep mine, take the file's, or keep editing, graded from what the diff shows.
What is the merge base?
The content hash the client loaded. The API remembers the text of every version it has seen, keyed by that hash, and uses it as the base when a write arrives with an older hash.
What does an agent see on conflict?
docs.update returns ok: false with the conflicts, the current document and the proposed text, instead of writing. The agent can re-read and retry; it never overwrites a person.
Does a no-op save create a commit?
No. Saves go through the canonical pipeline, so a document that did not change serializes to the same bytes and produces no diff and no commit.