Loom extension

The Ableton Extension that is Loom's only Live endpoint. Two things live here:

• The bridge (src/bridge.ts): a file queue under the extension's own storage directory that the Loom MCP writes requests into and reads outcomes from. Claim, expiry, session, replay journal, ownership ledger, structured outcome. Protocol loom.bridge/3. Everything Live-specific arrives through structural interfaces; src/extension.ts is the only file that touches SDK objects.
• "Loom: Generate" (right-click a Session clip slot or MIDI clip): runs the embedded Sensei runtime against the device evidence on the track and writes through the bridge's own write_clip -- same validation, same ownership ledger as a write the MCP asks for. A slot holding a clip Loom did not write is refused.

What the SDK cannot do (transport, meters, time signature, key write, preset loading, recording) is refused with a named reason, never approximated. A Drum Rack can be assembled from sample files (build_drum_kit: chain + Simpler per pad), which is how a preset kit is rebuilt from its own samples; journal_import carries an earlier extension id's replay journal over.

Versions

manifest.json is the one place the package version is written; the build fails if package.json differs and injects it into the bundle (surface_version: loom-extension/<version>). minimumApiVersion must equal SDK_API_VERSION in bridge.ts. The queue protocol (BRIDGE_PROTOCOL) is a separate number: the MCP refuses to mutate through a bridge that publishes another one.

Build, test, package

npm install                 # needs the SDK tarballs in vendor/ (see vendor/README.md)
npm run test:bridge         # fake Live, real queue code, 100+ checks -- no SDK runtime needed
npx tsc --noEmit
npm run package             # dist/loom.ablx

Identity: manifest name "Loom" + author "SubverseLab" give the extension id subverselab.loom (Live derives it from those two fields); the storage and bridge live under Extensions Data/subverselab.loom/. tests/fake_live_host.ts runs this bridge as a separate process over a fake set; mcp_server/tests/test_bridge_consumer_real.py drives the MCP against it. tools/measure_bridge.py is the real-Live acceptance run.

Developer Mode (npm start) needs the Live beta to be the only Live running; see vendor/README.md for the host quirks.