Right-click a person's avatar ▸ "Remove <name> from session", or
`collab.removePerson {client}`, when you host the session or own the file
on a server. The hub closes their connection as the end of the session for
them (close 1001: they keep their copy and don't reconnect) and bars their
address from that file while it runs, so the code or link they hold no
longer gets them in; everyone else stays connected.
Protocol addition within version 2: `Admin::RemovePeer {file, client}` on
an open hosting connection with the file's owner token (or the server
key). Older servers say they can't.
Tests: loopback (removed, can't rejoin, others stay), engine (host can,
guest can't, bad ids refused), codec round trip; the collab junk sweep
covers the new command.
Fixes from the security review of the public server:
- team libraries only in key-published files on open servers; unpacking
bounded by the file cap (zip bombs refused)
- byte-bounded send queues per connection and in all, a bound on bytes
waiting for the hub, per-address and global download budgets
- batches checked against the file, per-address and total caps as files
grow (refused with a Reject the app rolls back); the core's recent-batch
memory bounded in bytes; nothing confirmed when a log can't be written
- usage reports kept in memory; per-kind message caps checked while read
- layered IPv6 limits (/64, /56, /48), a global publish rate, connections
reserved for sessions, short idle timeout for one-shot requests
- revoked links and removed files cut library connections
- data directory 0700, server key 0600 from creation
- install.sh: SSH ports from sshd, ufw left off when other services
listen, unprivileged builds of the latest tag, settings checked before
use, own Caddy snippet; systemd memory and network caps; backups check
free space and say they hold the key
- linger reads raw bytes after an oversized frame (tungstenite asserted)
Two presence features for live sessions, with no accounts needed:
- **Cursor chat.** In a live session, `/` on the canvas opens a bubble in your colour at your pointer. What you type goes to everyone as you type, and others see it next to your cursor in place of your name tag. Enter (or clicking away) sends it and closes the box. On every screen it fades a few seconds after its last change (5 s, then a 1 s fade; with reduced motion it vanishes without fading). Escape takes it back at once and doesn't deselect. A box left open without typing closes by itself. Limits: 100 characters, control characters become spaces. Agents use `collab.cursorChat {text}`.
- **Spotlight.** Your avatar (top of the right panel) now has a menu with Spotlight me / Stop spotlighting (`collab.spotlight {on?}`). Everyone else follows your view and page, using the existing follow. People who join later are told by the server and follow too. Anyone who pans, zooms or presses Escape stops following, and a canvas banner ("Hana is spotlighting", Follow) lets them follow again. A newer spotlight takes over the old one. The presenter leaving or stopping ends it. The presenter sees a banner with Stop. After a reconnect, your spotlight goes out again.
- **Protocol: signals.** New `ClientMsg::Signal {kind, text}` and `ServerMsg::Signal {client_id, signal}` carry ephemeral presence. Signals never go into the document, the log or a saved state; the server keeps only who is spotlighting, for newcomers. The server cleans each signal: unknown kinds, malformed spotlights, a client's `ready` and anything over 1 KiB are dropped, and chat is capped and has control characters replaced. The app checks what arrives again before showing it. The hub rate-limits signals per connection (20 a second, bursts of 40) and drops the excess without closing the connection.
- **Compatibility, both directions.** A client that reads signals announces it with the word `signals` in its hello's `client_version`, and the server sends signals only to those clients, so older clients never see a message they can't decode. A server that takes signals answers with a `ready` signal after the welcome, and the client sends signals only after that, so older servers never get one; the app says the host runs an older version. Signals are kind plus text, so clients skip kinds added later and servers drop them.
- Engine: `Live` keeps `signals`, `chats`, `chat`, `spotlight` and `spotlighting`, all reported by `collab.peers`. UI: chat bubbles, the chat box, the spotlight banner (the existing canvas banner widget), the avatar menu and `ui.inspect` fields. Keymap: `/` maps to `collab.cursorChat` (Essential). Spanish labels for both commands, plus en/es UI strings.
- Docs: collab-protocol (messages, compatibility, Presence, security limits, agents), mcp.md, collaboration-parity rows, target-app-parity, ROADMAP, gaps, ui-parity.
The desktop app joins wss:// sessions (rustls with webpki roots, certificates always checked, clear errors; FIGCRAFT_CA_FILE for private authorities), with one TLS session shared by the reader and writer threads. figcraft-server stops gracefully on SIGTERM/SIGINT/SIGHUP/Ctrl+C, ships in Linux x86_64/aarch64 release archives, and docs/server.md gains a Deploy on a Linux server guide with a hardened systemd unit, Caddyfile, nginx config and Dockerfile in packaging/server.
figcraft-server hosts many files over the same hub the app uses for sessions, persists each as a checksummed snapshot plus an append-only log (synced before replies, compacted, damaged files skipped and reported) so restarts lose nothing confirmed, and gives per-file share links with edit or view access (hashed 128-bit tokens, revocable). The app can publish a file to a server and join server-hosted files; view-only tabs refuse edits. Protocol version 2.
* M9: collaboration: per-user undo, rejections, reconnect
Step 3 of docs/collab-protocol.md, the parts that don't need the transport:
- Per-user undo and redo (figcraft_collab::Client::{undo, redo}): each undoable batch is a step
(values before/after by target, nodes created/deleted). Others' batches ordered after the step
take its targets for good; creates invert to deletes (not when others built inside), deletes
re-create the subtree. An undo or redo waits for every earlier batch and is remade from the
confirmed state when it goes out; derived data follows as a follow-up batch.
- Rejections: refused batches leave the history (with an undo waiting on them) and queue a
Notice; the engine shows it through Session::message (the UI's toast).
- Offline queue and reconnect: Hello.resume {session, client_id, seq}; the server keeps a
bounded log and answers with the missed batches or a snapshot, plus what it did with the
client's batches (processed {last_batch, refused}); queued batches then go out.
Server::state / restore persist the session (client-id counter, log, session id).
- Presence carries editing_text {node, caret, selection}.
- Engine: documents in a live session (LiveDoc, Session::collab_*): commands, gestures and
groups sync as one step each; edit.undo / edit.redo route to the per-user history; remote
edits show under a gesture in progress. Outside a session snapshot undo is unchanged.
- Sim: dropped connections, undo/redo, and a checker that no undo reverts a change by someone
else its author had seen. New tests in undo_tests, reconnect_tests, collab_live_tests,
collab_undo_tests.
- CLAUDE.md / AGENTS.md: collab in the L2 layer list.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* M9: collaboration wording in the progress docs after per-user undo and reconnect
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* M9: protocol doc: what the engine's live-session tests cover
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
* M9: real-time collaboration protocol (design)
docs/collab-protocol.md: WebSocket sessions with a server-ordered,
per-property last-writer-wins document sync, client-scoped ids,
fractional positions for children, ephemeral presence (cursors,
selections, follow), per-user undo, hosting from the app first and a
self-hosted server next, and the implementation plan. ROADMAP gains M9.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* M9: collaboration core: ids, change sets, server ordering, convergence
Step 1 of docs/collab-protocol.md, no networking:
- Client-scoped node ids: Document::set_client_id makes alloc_id hand out
client << 32 | counter; single-user files allocate as before; the id
counter is no longer part of document equality.
- crates/collab (layer 2): the synced object/property model (every saved
Node field, plus document-level styles, comments, variables, images,
dev snapshots, library data), Change batches, an O(changed) diff, strict
and lenient apply, fractional sibling positions, snapshots.
- Server (ordering, validation, rejects with fixes) and Client (optimistic
view, replay under remote batches, author-side repair of derived data)
as pure state machines; binary (version byte + postcard, JSON values) and
JSON message forms, fuzzed decoders.
- Engine: normalize as the recompute hook, collab.diff.
- Tests: round trips over random real commands, an N-client convergence
fuzz test over delayed in-order links, junk batches.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* M9: fmt after merge
* M9: live sessions: host from the app, invite links, live cursors and presence
Step 2 of docs/collab-protocol.md, networking and presence half:
- crates/collab-net (layer 6): WebSocket transport (sync tungstenite, a
reader and a writer thread per connection, no async runtime), the
session host the app embeds (runs figcraft_collab::Server as the
authority, carries its messages), invite links, presence throttling
(~30 Hz, latest wins), limits (sockets, hello/idle timeouts, message
size, rate, slow clients), keep-alive, clean close, reconnect with
backoff; a browser stand-in until the web-sys client (step 4).
- engine: live session state (status, peers, presence, follow) and the
collab.host/stop/join/leave/peers/follow/cursor commands; the network
is reached only through the LiveLink the app installs.
- ui-egui: remote cursors (pointer drawn in code, name tag, gliding),
selection outlines (once documents sync), avatars in the right panel
with follow, the Share popover (start, invite link + URL with Copy,
stop), File > Join live session.
- desktop app and MCP headless session install the link; xtask layers
keeps networking crates out of L0-L5.
- Documents don't sync between apps yet (follow-up).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* M9: live sessions: document sync between apps
- The host's session runs figcraft_collab::Server seeded with the shared
document; every app (the host's too, through the hub without a socket)
is a collab Client. Guests open the host's file from the welcome as a
new tab; leaving keeps it as a local copy.
- Engine: after each local action (a gesture once it ends; nothing during
version or text previews) the session document is diffed into one
Changes batch; server batches go through Client::receive with
EngineRecompute and are installed with Session::apply_remote, which
never touches the undo history. Batches arriving mid-gesture wait.
- Transport: Changes/Reject/Welcome reach the engine as Event::Sync;
LiveLink::send carries batches in order; hellos are limited to 64 KiB,
joined clients to the core's message size.
- Tests: engine sync against a real Server (ids in the client's space,
one batch per gesture, remote edits skip undo, deferral, closing the
file leaves), three apps over loopback converging (create, move,
recolour, delete, rename) and a late joiner getting the server's state.
- Docs: collab-protocol, mcp, README, roadmap docs; the UI's
"cursors only" note is gone, replaced by the per-person undo caveat.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
bflatastic