oh-my-pi/docs/collab.md

Collab: Live Session Sharing

/collab shares your running session with other omp instances in real time. Guests render the same session natively in their own TUI — streaming assistant text, tool-call cards, footer state (cwd, model, context %, cost), ctrl+o expansion, /dump — no terminal mirroring. Guests can prompt and interrupt the agent; the host machine runs the agent and all tools.

Quick start

Host:

/collab

prints

Collab session started!
 • Join from another terminal: omp join "mgAYTZwEnpRQtca0CTgn-Q#gdJUbTovD94ofDaa8YvhY0-ty16w4fn8PgB6PLnoA30"
 • or any web browser: relay.omp.sh/#mgAYTZwEnpRQtca0CTgn-Q#gdJUbTovD94ofDaa8YvhY0-ty16w4fn8PgB6PLnoA30

The browser line is click-to-join (an OSC 8 hyperlink to the full https:// deep link): the relay serves the web guest client at /, and the room id + key ride in the URL fragment. From another omp (any directory, any machine), either form works:

/join relay.omp.sh/#mgAYTZwEnpRQtca0CTgn-Q#gdJU…

The guest's previous session is restored on /leave (or when the host stops).

Commands

Command	Effect
/collab	Start sharing (or re-print the link when already hosting)
/collab <relay>	Start sharing through a specific relay (relay.example.com, ws://localhost:7475)
/collab status	Show link + participants
/collab stop	Stop sharing
/join <link>	Join a shared session as a guest
/leave	Leave (guest) or stop sharing (host)

Link format

https://host[:port]/#<link>          → browser deep link (printed by /collab; /join accepts it too)
<roomId>#<key>                       → default relay (relay.omp.sh)
host[:port]/r/<roomId>#<key>         → custom relay, wss:// inferred
ws://localhost:7475/r/<roomId>#<key> → plain ws, allowed for localhost only

The trailing fragment (#<key>) is the room secret, base64url-encoded, in one of two strengths:

• Full link — 48 bytes: the 32-byte AES-256-GCM room key followed by a 16-byte write token. Grants prompting, interrupting, and subagent control.
• View-only link — the bare 32-byte key, no write token. Grants live read access only. Pre-token links parse as view-only.

In the browser deep link, everything after the first # — room id and key — is a URL fragment: it never appears in any HTTP request, and neither secret is ever sent to the relay.

End-to-end encryption

Every session payload (entries, events, state, prompts) is sealed with AES-256-GCM before it touches the socket. The relay sees only:

• room ids and connection counts,
• opaque ciphertext frames and their sizes,
• a 4-byte routing prefix (which guest a frame targets).

Possession of the link is the trust boundary: a full link reads and steers the session, a view-only link reads it. Share both like secrets.

Guest permission model

Two trust levels, enforced by the link itself — the host verifies the 16-byte write token at join and rejects writes from peers without it (they appear as read-only in the participants list, and the join notice says so).

Guests with a full link can:

• read the entire session (including the back-transcript at join time),
• prompt the agent (rendered with their name badge on every participant's transcript; the LLM sees the prompt text verbatim — names are display-only),
• interrupt the agent (Esc),
• use the Agent Hub against the host's subagents: live table and progress, chat (steers the host's subagent), kill, revive, and transcript viewing (fetched from the host on demand).

Guests with a view-only link can read everything live — back-transcript, streaming text, tool cards, subagent transcripts — but the host rejects prompting, interrupting, and agent control from them.

Everything that mutates the host session or machine is host-only: /model, /compact, /resume, /branch, bash (!), python ($), skills, etc. Guests keep a small local allowlist (/dump, /export, /copy, /help, /hotkeys, /theme, /settings, /leave, /collab, /exit).

Known v1 limit for guests: a turn already streaming when you join becomes visible from its next message boundary.

Web client

packages/collab-web is a standalone browser client for the same links — no omp install needed on the guest side. The relay serves it at /, which is what makes the /collab deep link click-to-join: https://<relay>/#<link> loads the client and auto-connects from the fragment. It renders the live transcript (streaming text, thinking, tool cards), a subagent panel with on-demand transcripts, and a composer with the same guest powers (prompt, interrupt, hub actions). Run bun run dev in the package for a local instance, bun run mock-host for an offline scripted host to develop against, and bun run build to emit a static dist/ deployable anywhere (HTTPS required for WebCrypto). The client never talks to anything but the relay, and the key stays in the URL fragment.

Settings

Setting	Default	Meaning
collab.relayUrl	wss://relay.omp.sh	Relay used by /collab when no relay is passed inline
collab.displayName	OS username	Name shown to other participants

Self-hosting the relay

The relay is a small content-blind Go service (omp-collab-relay, in the pi-www repo under relay/). It keeps no state beyond live connections and exposes:

• GET / — the static collab-web guest client (target of the /collab deep link),
• GET /r/<roomId>?role=host|guest — WebSocket upgrade,
• GET /healthz — liveness.

Run it:

go build -o omp-collab-relay .
RELAY_BIND=0.0.0.0:7475 ./omp-collab-relay

RELAY_BIND accepts host:port, a bare port (binds localhost), or a unix socket path (front it with a TLS-terminating reverse proxy — guests other than localhost require wss://). Then:

/collab my-relay.example.com

or set collab.relayUrl in /settings.

Architecture notes

Hub topology — the host is authoritative, guests never peer:

1. entry frames — durable session entries, broadcast pre-blob-externalization so images stay inline (guests cannot resolve host blob refs). Guests append them verbatim (ids preserved) to a replica session file under ~/.omp/collab/<roomId>.jsonl and into the agent's message array, which is why /dump and context estimates work.
2. event frames — live agent events, fed straight into the guest's normal event controller; rendering is events-only to prevent double-render.
3. state frames — debounced footer snapshots: streaming flag, the host's full model object and thinking level (applied to the guest's replica agent state, so model display and context-window math are native), host context numbers, and participants.
4. bus frames — mirrored task-subagent lifecycle/progress EventBus traffic, republished on the guest's local bus so the subagent HUD and status-line count work natively.
5. agents frames — agent-registry snapshots feeding a guest-local registry, so the Agent Hub table renders host subagents.

Guest→host: hello, prompt, abort, agent-cmd (hub chat/kill/revive), and fetch-transcript (incremental subagent-transcript reads answered by targeted transcript frames). The replica loads through the regular /resume machinery, so theming, ctrl+o, and transcript behavior are native by construction; the guest process never chdirs to host paths.