stack/docs/plans/2026-09-12_control-board-mvp.md

# Control board MVP — plan

Tracking: Gitea issue #1503 (https://git.mosaicstack.dev/mosaicstack/stack/issues/1503)

## Why

Jason is building blind. He has many agent sessions running across projects
and no single place to see what they are doing or who is waiting on him.
This plan replaces the registry line as the next thing to build. Registry
increment 3 stays parked; it does not resume by inertia. Decision record:
`MOSAIC-STACK-D-001` (Jason, 2026-09-12).

## What "done" looks like for the MVP

One web page lists my running agent sessions across projects, shows each
one's current status, and flags which ones are waiting on me.

Acceptance:

- Jason opens one page and sees every live pi agent, grouped by project.
- Each agent shows a state in plain words (working, waiting, error,
  offline, idle, unknown).
- A "waiting on you" section sits at the top of the page.
- The page refreshes itself. Jason does not have to reload it by hand.
- Every state on the page comes from a status file written by the scanner,
  not from a guess made in the page itself.

## Three steps

### Step 1 (today): plan, ticket, scanner

- Write this plan and open the Gitea ticket.
- Build the status scanner script with tests. Running it writes one status
  file per agent under `<dataRoot>/board/`.
- This step does not touch any page or launcher. It only produces files.

### Step 2: the web page

- Build a page that reads the status files the scanner writes and shows
  them grouped by project, with the waiting-on-you section on top.
- The page refreshes itself on a short timer. The small local server behind
  it may re-run the scanner on each refresh so the files stay fresh. No
  separate daemon is needed for this step.

### Step 3: daily use and fixes

- Jason uses the page every day for real work.
- He says what is wrong or missing.
- Fix that one thing, then repeat. No new scope beyond what he actually hits.

### Step 3 log

**2026-09-12 — liveness follows the tmux pane, not just the session.**
Jason found agents marked "waiting" that were actually dead: their tmux
session still existed but no longer ran `pi` (it had exited to a shell or
something else). The scanner now checks which program each tmux pane is
running (`tmux list-panes -s -t '=<session>' -F '#{pane_current_command}'`) and only counts an
agent alive if a pane is running `pi`. A tmux session with no `pi` pane is
now "offline" instead of "waiting".

**2026-09-12 — a "Seen" mark for rows that don't need a reply.** Jason
noticed most "waiting" rows were completion reports, not real asks, and
they kept cluttering "Waiting on you". The page now has a "Seen" button on
waiting/error rows; clicking it stores the row's `lastActivity` in
`<dataRoot>/board/seen.json` (via `POST /api/seen`) and drops the row out
of "Waiting on you" while keeping its state visible. The mark clears
itself the moment the agent writes anything new, and "Unsee" puts a row
back by hand. `seen.json` is only ever written by that click, never by a
scan.

## How the scanner decides state

The scanner reads the newest pi session log for each agent, plus whether
the agent's tmux session is still alive. It does not guess; it only reports
what the log and tmux say.

| State   | Plain-words meaning |
|---------|----------------------|
| working | The agent is in the middle of a turn: thinking or running a tool. |
| waiting | The agent finished its turn. It is your move now. |
| error   | The agent's last turn ended in an error, was aborted, or was cut off. Go look at it. |
| offline | There is no live tmux session for this agent right now. |
| idle    | The agent is live but has not had a conversation yet. |
| unknown | The scanner could not ask tmux (missing or not answering). It does not assume the agent is alive. |

Two kinds of agents are scanned today:

- Repo agents: session logs live under `.pi/state/<agent>/sessions` in a
  project checkout, on the default tmux socket.
- Fleet agents: session logs live under
  `~/.mosaic/fleet/agents/<agent>/.pi/agent/sessions`, on the tmux socket
  named `mosaic-fleet`.

## Where files go

- One file per agent: `<dataRoot>/board/sessions/<project>/<agent>.json`
- One summary file for the whole board: `<dataRoot>/board/index.json`
- `dataRoot` comes from `~/.config/mosaic-dev/config.json`. If that config
  is missing or broken, the scanner refuses to run. It does not guess a
  fallback location.

Board files are derived. They can be deleted and rebuilt at any time by
running the scanner again. They are NOT run records and they are not
evidence under the repository's write-once rules.

## Commands

Scan once and print the table:

```
node packages/control-board/src/cli.mjs scan --print
```

Start the page (step 2), then open http://127.0.0.1:7331/ in a browser:

```
node packages/control-board/src/cli.mjs serve
```

Tests:

```
node --test packages/control-board/tests/
```

## Boundaries

- No changes to any launcher script.
- No new files at the repository root.
- No secrets read, stored, or printed.
- No daemon yet. In step 1 the scanner is run by hand. In step 2 the page
  may trigger it on refresh; nothing runs it on a schedule.
- No changes to `packages/mosaic`.
- This plan does not authorize push or merge beyond whatever the existing
  refactor-branch plan already allows.