Every signed Change blob now carries an optional message string, analogous to a git commit message. Refs no longer carry a message field. The publish UI, CLI, activity feed, and Versions panel all read the message off the Change rather than the Ref.

The first iteration of this feature stored message on the Ref blob. We reversed that decision before merge.

The unit of "what changed" in this system is the Change blob — like a commit in git. A Ref is a pointer/branch that names a path and points at heads. Tombstone Refs and redirect/republish Refs do not introduce new content; they only re-aim a path. There is no content delta to describe on those Refs, so a message field there has no consistent meaning.

Putting the message on the Change also matches the git mental model the rest of the API already leans on:

• Change ≈ commit (signed, identified by content, has a message).

• Ref ≈ branch ref (a moving pointer, not a description).

This change keeps message scope narrow and meaningful: only content changes carry one. Tombstones and redirects do not.

On the Go side, Message is a top-level field of blob.Change:

type Change struct {
    BaseBlob
    Genesis cid.Cid    `refmt:"genesis,omitempty"`
    Deps    []cid.Cid  `refmt:"deps,omitempty"`
    Depth   int        `refmt:"depth,omitempty"`
    Body    ChangeBody `refmt:"body,omitempty"`
    Message string     `refmt:"message,omitempty"`
}

Top-level (sibling of Body/Deps/Depth) was preferred over nesting inside ChangeBody. The body is reserved for the document operations themselves; metadata about the publish event lives at the same level as Genesis, Deps, and Depth.

The omitempty CBOR tag means changes without a message produce identical bytes to before this feature existed — backward-compatible by construction.

For SQL-side queryability, the indexer copies Message into structural_blobs.extra_attrs->>'message', alongside title and metadata. This lets the API surface the message without re-decoding the blob.

Proto schema changes (proto/documents/v3alpha/documents.proto):

• Added string message = 9; on CreateDocumentChangeRequest (kept from the original Ref-message branch — same field number, different semantics).

• Added string message = 7; on PrepareChangeRequest so the daemon can embed the message into the unsigned Change blob it returns to client-side signers.

• Added string message = 5; on DocumentChangeInfo so GetDocumentChange and ListDocumentChanges surface it.

• Removed string message = 9; from CreateRefRequest. Field number reserved (reserved 9;).

• Removed string message = 9; from Ref. Field number reserved (reserved 9;).

Reserving the field numbers prevents accidental reuse if anyone rebuilds an older client and tries to populate them.

Client SDK (frontend/packages/client/src):

• createChangeOps and createDocumentChange accept message?: string. When set, it is added to the unsigned Change CBOR top-level.

• createVersionRef, createTombstoneRef, createRedirectRef no longer accept message. Removed entirely — not deprecated, since the branch hasn't shipped.

• signDocumentChange no longer accepts message. The message is expected to be already embedded in the unsigned Change bytes (either by the daemon's PrepareChange handler, or by a client-side createChangeOps call).

The branch had not yet merged when this decision was made. There are no shipped Refs in the wild with Ref.Message, so we drop the field cleanly with no migration shim and no fallback read path.

Forward-compatible: clients running older code that don't send message simply produce changes without the field, and the indexer treats absence as "no message" (omitempty).

End-to-end test path used during implementation:

1. direnv exec . plz run //proto/documents/v3alpha:go.gen to regenerate proto bindings.

2. direnv exec . go test ./backend/blob/... ./backend/api/documents/v3alpha/... -count=1 — all pass, including the new TestChangeMessageRoundTrip.

3. direnv exec . pnpm typecheck — clean across all 16 frontend workspaces.

4. direnv exec . pnpm test — 414 frontend tests pass.

5. Manually: open desktop app, create draft, type content, click Publish, type a message in the textarea, confirm publish.

6. Manually: open the Activity feed accessory and verify the italic message line under the publish event.

7. Manually: open the Versions panel and confirm the message appears next to the change.

8. Manually: seed document create … -m "cli test" → seed document update … -m "cli edit" → verify both messages appear via the API.

9. Manually: tombstone or redirect via CreateRef — confirm no message field is present (it's gone from the proto).