Record which machine runs each build

[MaggieAppleton]

What and why

The Build tab's new status card (next PR) shows which machine a build runs on, to everyone who can see the build. Today a build stores only its in-memory connectionId, which means nothing after a reconnect or restart and is deliberately hidden from other people.

• Persist the machine. When a build or rebuild is queued, it stores the paired machine's durable machineId, plus machineService when that connection ran as a background service (the machine record itself does not keep this). Both are optional in buildSchema, so builds stored before this still restore. Builds live in the document sidecar JSON, so there is no migration. They are written by the existing persistExclusive before the build is acknowledged or announced.
• Name it in the snapshot. ImplementationSnapshot.buildMachines maps build id to { label, service, connected? } for the builds the snapshot shows: build, live.rebuild, and the live build (live.buildId). The label is read from storage.machines, so a rename shows up. A build with no machineId or no machine record has no entry; there is no fallback.
• Online status stays private. connected is sent only to the build's own starter, the same rule as live.builderConnected. Other people see the name and icon, never whether the laptop is online. withoutConnection and builderConnected are unchanged.
• Live updates still go through plan:implementation → the client re-reads GET /implementation, so the one snapshot read covers broadcasts as well.

flowchart LR
  A["Build / rebuild queued<br/>on a live connection"] --> B["queueBuild / queueRebuild<br/>build.machineId = connection.machineId<br/>build.machineService = about.service"]
  B --> C[("Sidecar JSON<br/>persistExclusive")]
  C --> D["announceImplementation<br/>plan:implementation"]
  D --> E["GET /implementation"]
  E --> F["storage.machines.get(machineId)<br/>label"]
  F --> G["buildMachines[buildId]<br/>{ label, service }"]
  G --> H["Every viewer:<br/>label + icon"]
  G --> I["Build's starter only:<br/>+ connected"]

Loading

Tests

• DEMO_PERSONAS=off bun test apps/server/src/tasks/ apps/server/src/experiments/spike-host.test.ts: 157 pass.
  • Everyone sees a started build's machine; only its starter gets connected.
  • A living document's first build and its rebuild name their machine to a non-builder, who still gets no builderConnected.
  • A legacy build without machineId restores and the snapshot has no buildMachines.
  • machineId survives closing and reopening the document.
• bun run types: server and protocol are clean. bun run ci fails only on git-ignored apps/web/src/design-jig/ files.

🤖 Generated with Claude Code