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feat(bengle): LED strip palettes + live preview over MMR - #464

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feat(bengle): LED strip palettes + live preview over MMR#464
ChampionDesigns wants to merge 18 commits into
decentespresso:mainfrom
ChampionDesigns:feat/bengle-led-strip

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@ChampionDesigns

@ChampionDesigns ChampionDesigns commented Jul 16, 2026

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Stacked PR — B-6 of 10. Builds on #463 (feat/bengle-scale-calibration). Until that merges this PR's diff includes its commits; please review/merge in order B-1 → B-10.

A Bengle has front and rear light strips, and the app has had a full REST surface for them since the capability landed: read the configuration, write all three zones in both awake and sleeping modes, commit, reset. None of it did anything. The capability was a scaffold written before the firmware wire spec was published, so every endpoint address was null, every write was swallowed, and the code logged one line per session and returned success. A user who set the strips to a warm white got a 200 OK and a machine that stayed exactly the colour it already was, and a GET afterwards cheerfully echoed back the colour they had asked for, because the value never left the app's own cache. This PR wires the capability to the six real firmware registers, hydrates the cache from the machine on connect so the app stops inventing state, and adds a live-preview endpoint so a colour picker can show a colour on the strip without storing it.

Summary

  • Problem: LedStripCapability was a stub. BengleLedEndpoint returned null for every uuid and representation; setLedStrip, commitLedStrip and resetLedStrip all no-opped with a once-per-session info log. The REST endpoints returned success and wrote nothing to the machine. The in-memory cache was seeded all-off and never corrected, so GET /api/v1/machine/ledStrip reported black on a machine that was glowing.
  • Why it matters: The LED strip is one of the two things a Bengle owner can see the app is supposed to control (the other being the cup warmer, B-7). It failed silently in the worst way available: 200 OK, a cache that agreed with you, and a machine that ignored you.
  • What changed: Six firmware MMR registers replace the null endpoints - four persisted palette slots (FrontLEDAwake 0x00803898, FrontLEDSleep 0x008038A0, RearLEDAwake 0x0080389C, RearLEDSleep 0x008038A4) and two live-colour slots (FrontLEDColor 0x00803890, RearLEDColor 0x00803894). initLedStrip now hydrates the cache from the four palette registers on connect. Two new endpoints, POST /api/v1/machine/ledStrip/preview and POST /api/v1/machine/ledStrip/preview/clear, drive the live slots so a UI can preview the sleep colour while the machine is awake.
  • What did NOT change (scope boundary): The LedStripState JSON shape is unchanged - still three zones by two modes. GET, PUT, /commit and /reset keep their paths and their status codes. No skin ships in this PR; the Streamline LED UI is a separate repo and a separate review.

Change Type (select all)

  • Bug fix
  • Feature
  • Refactor required for the fix
  • Docs
  • Security hardening
  • Chore / infra
  • Plugin (DYE2 or bundled skin)

Scope (select all touched areas)

  • BLE transport / device comms
  • REST API / handlers
  • WebSocket API
  • Machine state / shot logic
  • Scale / weight / flow
  • Profiles / beans / grinders / workflows
  • WebUI skins
  • Plugins / JS runtime
  • UI / Flutter widgets
  • Storage / Drift database
  • CI / build / infra
  • Docs / specs

Linked Issues

  • Closes #
  • Related # (Bengle stack B-1 through B-10)

Root Cause (if bug fix)

  • Root cause: The capability was written against a firmware wire spec that did not exist yet. BengleLedEndpoint.uuid and .representation were hard-coded null with a // TBD with FW comment, and the mixin treated a null wire as "capability not yet wired" and no-opped by design. That was the right call at the time. What made it a bug rather than a placeholder is that the REST layer never learned about it: the handler returned 202/200 exactly as it would for a real write, and the cache absorbed the value so a read-back confirmed the lie.
  • Missing detection or guardrail: Nothing distinguished "the capability succeeded" from "the capability decided to do nothing". A stub that returns success is indistinguishable from a working feature at every layer above it, and the tests pinned the stub (they asserted the no-op) rather than the behaviour.
  • Contributing context: The registers were in the firmware the whole time. They are in the firmware register table, and the app-side comment in the previous code said the wires were unpublished. They were simply never reconciled.

Regression Test Plan (if bug fix or refactor)

  • Coverage level that should have caught this:
    • Unit test
    • Integration test (mock transport edge)
    • End-to-end test (simulate=1 + curl/websocat)
    • Existing coverage already sufficient
  • Target test or file: test/unit/models/device/impl/de1/unified_de1/led_strip_capability_test.dart (+392 lines), plus test/unit/models/device/impl/bengle/mmr_contract_test.dart (the four palette registers and the two live registers are now registered with the firmware contract checker).
  • Scenario the test should lock in: Drive a real Bengle over FakeBleTransport and assert the bytes on the wire, not the cache: a setLedStrip writes four MMR frames to the four palette addresses in 0x00RRGGBB form; a previewLedColor writes the two live addresses and does not touch the palette or the cache; clearLedPreview writes the cached awake palette back to the live addresses; initLedStrip reads the four palette registers into the cache; and a read that throws leaves the cache seeded all-off rather than failing the connect. The contract test additionally fails CI if any of these six addresses, lengths or scales drift from assets/api/bengle_hw_v1.yml.
  • If no new test added, why not: N/A.

Documentation Obligations (required)

  • API spec updated: assets/api/rest_v1.yml - GET gains the connect-time-hydration contract; PUT describes the persist-on-write semantics and the ignored frontSwitch zone; /commit and /reset are re-described (see below); the two /preview endpoints are new.
  • API docs updated: doc/Api.md
  • Plugin docs updated: doc/Plugins.md
  • Skin docs updated: doc/Skins.md
  • Profile docs updated: doc/Profiles.md
  • Device docs updated: doc/DeviceManagement.md
  • N/A - no docs affected

The e2e scenario docs/e2e/decent-app/scenarios/bengle-led-strip.md is refreshed in the same commit.

Security Impact (required)

  • New or changed REST endpoints? Yes - POST /api/v1/machine/ledStrip/preview and POST /api/v1/machine/ledStrip/preview/clear. Both are Bengle-only (404 on any other machine) and both sit on the same unauthenticated local web server as the existing LED endpoints, which already accept arbitrary colours. The new surface is a colour, on a light. It grants no reach a caller did not already have through PUT /api/v1/machine/ledStrip.
  • New or changed WebSocket topics? No
  • New or changed network calls? No
  • BLE/USB surface changed? Yes - six new MMR reads/writes, all Bengle-only. They are registered with the contract checker, which fails CI if an address drifts from the firmware contract file.
  • File system access changed? No
  • Plugin sandbox boundary changed? No

User-Visible Changes

The LED strip endpoints now actually change the colour of the lights. GET /api/v1/machine/ledStrip returns the colours stored on the machine after a connect, rather than all-off, so a fresh app install shows the user their real palette. Two new endpoints allow a live preview. POST /commit and POST /reset keep working and keep their status codes, but their meaning has changed - see the deliberate choices below. Their request bodies are now required: false, which is a relaxation, not a break.

Verification

Local gates (run before pushing)

  • flutter analyze - clean (No issues found!)
  • flutter test - 2170 tests pass on this branch at 89d421f1 (B-5 was 2150, so this branch adds 20).
  • (cd packages/dye2-plugin && npm run build) - plugin builds

Manual verification (if applicable)

  • OS / platform tested: Linux (analyzer, tests, and a simulated end-to-end run).
  • Simulated devices? (simulate=1): Yes - against MockBengle, GET /api/v1/machine/ledStrip returns three zones by two modes in 16-bit RGB; POST /ledStrip/preview returns 202; POST /ledStrip/preview/clear returns 202.
  • Real hardware? (DE1/Bengle/scale): No.
  • What you personally verified and how: the wire bytes, through the tests. FakeBleTransport captures the MMR frames and the assertions are byte-exact against the six addresses.
  • Edge cases checked: a failed hydration read on connect (the cache stays all-off and the connect still succeeds); a preview followed by a clear (the palette registers are untouched throughout); a 16-bit colour round-trip through the firmware's 8-bit-per-channel encoding.
  • What you did not verify: I have not lit a real LED. The six register addresses come from the firmware register table and are pinned by the contract checker against assets/api/bengle_hw_v1.yml, but no one has yet confirmed on hardware that writing FrontLEDAwake turns the front strip that colour. MockBengle.previewLedColor is deliberately a no-op, so the simulated run proves the REST plumbing and nothing about the machine. This should be smoke-tested on a real Bengle before merge.

Evidence

  • Test output (2170 pass; the new capability tests fail against the stubbed code, which is the point)
  • Log snippets
  • Screenshot / recording (UI changes)
  • curl output (the two new endpoints, against simulate=1)

Compatibility & Migration

  • Backward compatible? Yes, with one semantic caveat. Every existing path, method and response shape is unchanged, and the two endpoints whose request body was required: true now accept an empty body. But /commit and /reset no longer mean what their names say (below). A client that calls PUT then /commit keeps working; the /commit is now redundant rather than necessary.
  • Config / env changes needed? No
  • Database migration needed? No

Deliberate choices worth your review

  • /commit and /reset are now vestigial, and I kept them anyway. The four palette registers are PERM_RWD in firmware - they persist on every write. There is no separate commit register, so the live/persist split the API was designed around does not exist on the wire. Rather than break the API I made commitLedStrip() re-assert the cached palette (a harmless idempotent re-write) and resetLedStrip() re-read the registers into the cache. That means /reset is a cache re-hydrate, not a rollback - it returns whatever was last written, so it cannot undo a PUT. The spec now says so in as many words. The honest alternative is to deprecate both endpoints; I did not want to make that call unilaterally on someone else's public API.
  • The frontSwitch zone has no register and is silently ignored on write. The physical switch light mirrors the front strip in firmware; there is no independent control. I kept the zone in LedStripState for API symmetry and made reads mirror the front strip's values into it. The alternative - reject a request that sets frontSwitch to something different - is arguably more honest, but it would break the existing three-zone request shape. This is documented in rest_v1.yml but a client cannot detect it programmatically.
  • Color16 is 16-bit per channel and the firmware is 8. Writes take the high byte of each channel; reads byte-replicate back (0xAB becomes 0xABAB). Round-trips are lossless for anything that originated as 8-bit colour, which is every colour picker I know of, but a genuinely 16-bit source loses its low byte silently.
  • A missing or malformed front/back in a preview request previews black. That is Color16.fromJson's existing semantics, not a decision I made here, but it means POST /ledStrip/preview with {} turns both strips off. I documented it rather than special-casing it, because the alternative is to diverge from how Color16 is parsed everywhere else in the API. If you would rather have a 400 there, say so and I will add it.

Risks & Mitigations

  • Risk: The connect-time hydration read fails (older firmware, a flaky transport), the cache stays all-off, and the user then clicks "clear preview" - which writes the cached awake palette, i.e. black - turning the strips off when they meant to restore them.
    • Mitigation: The failure path is logged at warning and the spec documents the exact sequence. It is bounded: any PUT or POST /reset repairs the cache. I chose a tolerant hydration (a failed read never fails the connect) over a strict one, because a Bengle that cannot connect because its LEDs would not answer is a much worse failure than a strip that goes dark.
  • Risk: The register addresses are wrong or the byte order is wrong, and the strips do something surprising on a real machine.
    • Mitigation: The contract checker pins all six against assets/api/bengle_hw_v1.yml, so they cannot silently drift. It does not, however, prove they were right to begin with - see "what you did not verify" above. A hardware smoke test is the mitigation, and it has not been done.

ChampionDesigns and others added 18 commits July 15, 2026 23:16
BLE discovery picks the machine class from the advertised name before a
connection exists, but the authoritative Bengle identity is the v13Model
MMR (0x0080000C, model >= 128 => Bengle), readable only after connect.
A Bengle advertising a DE1-style name therefore landed as a plain
UnifiedDe1 with every Bengle feature dark, and a DE1 mis-advertising
"Bengle" would be driven with the wrong protocol.

- UnifiedDe1 gains an `isBengle` flag set from the (already-read)
  v13Model in onConnect, plus the three seams re-resolution needs:
  `dataTransport` (rebuild over the same live transport),
  `adoptIdentityFrom` (carry connect-time identity so the re-resolved
  instance's onConnect short-circuits the MMR re-reads instead of
  hanging on an empty response queue), and `detachTransport` /
  `UnifiedDe1Transport.detach()` (release the discarded interim's
  wrapper WITHOUT disposing the shared transport the replacement owns —
  else a lingering serial readStream listener double-parses every line).
- New pure resolver `resolveMachineForModel` (de1_resolver.dart):
  same instance when name-picked class matches the model; otherwise a
  fresh Bengle/UnifiedDe1 over the same transport. Mirrors the serial
  path, which already class-dispatches on v13Model >= 128.
- De1Controller.connectToDe1 calls it after onConnect, finishes
  connecting the resolved machine, and tears the interim down. The
  idempotency guard now keys on deviceId, not object identity (post-swap
  _de1 is a different object for the same physical machine). A demoted
  Bengle interim additionally has EVERY capability its onConnect
  initialised disposed (integrated scale + LED strip today) — its
  Bengle.onDisconnect never runs, so anything less leaks the capability
  subjects. This disposal is deliberately exhaustive; the reference
  implementation missed one capability and the controller-level test
  now locks the full set.

DE1 behavior is unchanged: model 1..7 leaves isBengle false and the
resolver returns the same instance untouched.

Tests: bengle_detection_test (flag semantics, boundary 128, name-vs-
model authority), de1_resolver_test (promote/demote/no-swap/identity
carry/detach safety), de1_controller_resolve_test (controller-level
promote + demotion disposal + deviceId guard; disposal test fails when
any capability dispose is removed).
Doc gate: doc/DeviceManagement.md "Bengle: name is a hint, v13Model is
authoritative" section.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The public @Protected writeMmrScaled (the path every Bengle capability
scaled write rides) integerized with toInt(), which truncates: IEEE-754
makes 2.3 * 100 == 229.999…, so a 2.30 g stop-at-weight target landed
on the wire as 229 — a whole centigram low. de1plus rounds this write
class, so round() restores byte parity.

The base-DE1 private _writeMMRScaled (flush/hot-water/steam/heater/cal
flow setters) deliberately KEEPS toInt(): de1plus truncates exactly
those (e.g. set_flush_flow_rate `int(10*rate)`), and rounding them
would change bytes on shipped DE1 hardware. Both behaviors are now
test-pinned so neither can be "unified" away — setSteamFlow(2.3) must
land 229 while a capability write of 2.3 at x100 must land 230.

Also fixes the latent MMRItem.steamStartSecs declaration: it carried
the default 1.0 scales while firmware MMR.def has mult = 100 (seconds
x100 on the wire). Nothing reads or writes it today, so no byte-level
behavior changes, but the first wired setter would have written 100x
low; the bengle_hw_v1.yml contract checker (added in this PR) fails on
exactly this class of drift, and this declaration is what makes it run
green.

Tests: protected_surface_test — "writeMmrScaled rounds, not truncates"
(230) and "_writeMMRScaled truncates like de1plus" (229), locking both
directions of the split.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The post-connect large-ATT-MTU request was Android-only. The Bengle's
0xA013 shot-sample notification is 28 bytes — above the 23-byte ATT
default payload — so on iOS/macOS/Windows the stream would truncate
unless the OS happened to negotiate a larger MTU on its own. Request
517 on every platform except Linux:

- Linux stays skipped: BlueZ manages the MTU itself and universal_ble
  does not expose requestMtu there.
- The 200 ms post-connect settle stays Android-scoped (it works around
  an Android service-discovery race on tablet SoCs; other platforms
  don't need the delay).
- Failure remains non-fatal (log-and-continue): the DE1/Bengle BLE
  module self-negotiates up to 247 on connect regardless, so the client
  request is belt-and-suspenders — a rejection must never abort the
  connect.

Benign for a plain DE1: a larger MTU only reduces GATT round-trips.

Adds a `@visibleForTesting isLinuxOverride` seam (dart:io Platform is
not fakeable in unit tests) so the platform gate is testable.

Tests: universal_ble_transport_mtu_test — 517 requested on non-Linux,
Linux skipped, failed negotiation non-fatal (fake UniversalBlePlatform,
same shim pattern as universal_ble_transport_recovery_test).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The Bengle MMR register layout is hand-declared twice — the firmware
MMR.def X-macro table (C, compiled into the chip) and the app's Dart
enums. Two hand-maintained copies in two languages drift silently, and
a silent drift means the app writes the wrong register. This is not
hypothetical: steamStartSecs shipped with default 1.0 scales against a
firmware mult of 100 (fixed in the previous commit), and nothing could
have caught it.

- assets/api/bengle_hw_v1.yml: machine-readable contract, one row per
  MMR register (address/length/perms/mult/kind/range/semantics), plus
  the 0xA013 BengleShotSample packet layout and the ASCII serial-verb
  contract as human sections. Distilled from firmware MMR.def at
  ben/tablet-packet-wiring 0381e7ab58eb5b5ee36c14b0bef123ea3cfe4f2e
  (build-90 — the hardware-validated pin); contract_version 1.
  Normalization rules (raw-wire-unit bounds, the inert v13Model
  mult=1000 column, ENTRY-perms authority) are binding and documented
  in the header.
- test/unit/models/device/impl/bengle/mmr_contract_test.dart: a Dart
  test riding the normal `flutter test` CI job. Asserts every
  app-declared register against the contract: address/length/scale
  exactly, range as app-subset-of-contract; perms not asserted in v1
  (the app enums carry none). On this branch it registers the 30
  shared-DE1 MMRItem rows; each later Bengle capability branch appends
  its own enum's rows per the extension protocol in the file header.
- doc/bengle/HW-CONTRACT.md: the coordination protocol — change flow
  (MMR.def change -> regenerate contract -> bump contract_version ->
  update enums -> checker enforces; both PRs cite the version), the
  back-pointer text for firmware MMR.def, the proposed
  contract/feature-version MMR gate, known firmware-side TODOs the app
  degrades gracefully around, and the current drift snapshot.

The contract home is reaprime (beside rest_v1.yml/websocket_v1.yml)
because the consumer and the CI live here; the layout authority stays
firmware MMR.def — the chip decides.

Tests: mmr_contract_test (35 checks green: parse + version pin +
30 register rows + informational coverage).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The app has accepted and persisted the `bengle` simulated-device type
since MockBengle landed (SimulatedDevicesTypes { machine, scale,
sensor, bengle }; POST /api/v1/settings validates entries through that
enum), but both simulatedDevices schemas in rest_v1.yml still listed
only [machine, scale, sensor] — a client following the spec could not
discover the value, and an agent following the spec would flag a valid
request as invalid. The spec is authoritative; this brings it back in
line with the shipped handler.

The device `type` enum at the top of the file is deliberately
untouched: a simulated Bengle presents as type `machine` in device
listings.

Tests: none (spec-only correction; the accepting handler behavior is
pre-existing and already exercised by settings handler tests).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
CONTRIBUTING requires formatting your own changes (the CI format step is
advisory only because the pre-existing codebase predates the Dart 3.7+
tall style). Of the seven format-dirty files this branch touches, the six
pre-existing ones were already dirty at upstream/main — reformatting them
here would be exactly the untouched-file churn CONTRIBUTING forbids — but
this test is net-new on the branch, so it alone owes a clean format.
Whitespace-only; no assertion or behavior changes (file re-run green).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
…ndroid probe

The Android USB pre-filter dropped any port whose productName wasn't
'DE1', 'Half Decent Scale', or something containing 'Serial' — before
the class shortcuts or the v13Model probe ever ran. That made the
existing Bengle shortcut dead code, and a real Bengle undetectable over
USB on Android: current firmware enumerates with the pico-sdk DEFAULT
descriptors (VID:PID 0x2E8A:0x000A, product string "TinyUSB Device" —
captured from hardware 2026-07-10), which pass neither check.

Fix, in two additive halves ORed at the gate:
- `serialProbeAllowsProductName` (utils.dart): the old name semantics
  plus 'Bengle' and null names (Android often reports null before
  permission is granted). Exact, case-sensitive matches on purpose —
  the descriptor strings are fixed, and loosening them widens the
  3-second probe's reach onto unrelated devices.
- `bengleProbeCandidateIds` (usb_ids.dart): 0x2E8A:0x000A qualifies a
  port for the identification PROBE only. `bengleUsbIds` stays EMPTY —
  the pair is every default pico-sdk CDC device, so direct
  instantiation would claim random hobby boards as espresso machines;
  the v13Model read stays the authority. (0x2E8A:0x000C is the Pi
  debug probe and must not match.)

The gate is extracted as a @VisibleForTesting static
(`shouldProbeUsbDevice`) so the OR-combination — the actual fix — is
unit-tested, not just the predicates. Every previously admitted name
still passes; plain-DE1 behavior is unchanged. Auto-permission for the
Bengle VID:PID was already upstream in device_filter.xml (verified,
not re-added).

Tests: serial_probe_name_gate_test (name-gate + probe-candidate
predicates + OR call-site groups, 13 tests).
Doc gate: doc/DeviceManagement.md — Android name-gate paragraph +
VID:PID probe-candidate wording in the serial detection list.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Three USB-serial correctness fixes in the shared transport. All are
serial-only code paths (`transportType == TransportType.serial`); the
BLE path is byte-for-byte unchanged.

- FIX-17.2 — length-exact <F> frames. The firmware serial parser
  consumes exactly getLengthForCID('F') = sizeof(T_WriteToMMR) = 20
  bytes per <F> frame; BLE tolerates a short final DFU chunk, serial
  drops the whole frame and desyncs to the next '<'. Zero-pad short
  writeToMMR frames (the DFU uploader's final image chunk is the only
  short-frame producer). The Len byte carries the true payload length,
  so the padding is inert. Other endpoints are never padded — their
  structs are shorter by design.

- FIX-17.4 — serial reads. The ASCII serial view has no read verb.
  Reads now come in three shapes: continuously-subscribed endpoints
  serve the latest received frame; versions/temperatures/calibration
  are one-shot <+X> → [X] → <-X> round trips over plain broadcast
  controllers (NOT BehaviorSubjects — a read must resolve with the
  fresh frame its own <+X> provoked, never a cached one), bounded by a
  2 s timeout; endpoints the firmware can never emit throw a
  descriptive UnsupportedError instead of UnimplementedError, so the
  raw WS API surfaces a clean error instead of crashing the read. The
  listener is armed BEFORE the <+X> write, the armed future is
  .ignore()d so a throwing request write can't leak an unhandled async
  timeout, and the <-X> is sent in a finally so a failed read never
  leaves a subscription eating downlink budget.

- FIX-17.5 — keepalive. BLE and USB share one serial view in the
  firmware, arbitrated by a last-writer-wins Source flag: any stray
  BLE-module byte silently steals the notify stream from a passively-
  listening USB client. A 5 s <+N> keepalive actively re-asserts the
  USB source, and — because the firmware treats add-notify as a
  force-update — doubles as a resync for the checksum-less framing.
  Fire-and-forget with catchError: a failing write means the port is
  dying, which the read-side onError/onDone already handles.
  Cancelled on disconnect(), dispose(), and detach().

serialKeepaliveInterval/serialSingleReadTimeout are injectable ctor
test seams (fakeAsync stalls on the root-zone _nullFuture that
broadcast-subscription cancels return, so the timer tests run on real
shortened time). Composes with upstream's no-op-reconnect teardown
(075efbb): that path is BLE-gated and untouched.

Tests: FakeSerialTransport helper (inbound-capable),
serial_parity_test — pad/round-trip/timeout/UnsupportedError/keepalive
groups plus parser edge cases (chunk-split reassembly, leading junk,
4096-overflow dump + resync), the unhandled-async-timeout guard, and
the requestedState-aliases-stateInfo pin.
Doc gate: doc/DeviceManagement.md "USB/serial transport behaviour
(DE1 family)" block (reads / length-exact frames / throughput / link
arbitration).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
USB/serial discovery runs fine with the Bluetooth adapter off (the
device scan runs every discovery service in parallel and records
per-service failures), but TWO separate gates in the scan flow buried
the results behind a full-screen Bluetooth error, so a wired-only
setup could never reach its machine picker (bench-reproduced — fixing
only one gate leaves the picker hidden behind "Connection error:
Bluetooth is turned off."):

- the guardian's adapter-error view took precedence over everything;
- the connection manager's STICKY adapterOff ConnectionError claimed
  the idle-phase error view.

Both are now demoted by `busyWithoutBle` — anything in flight that
works without Bluetooth: an active machine/scale connect, a pending
picker, found machines, or machines streaming in via
DeviceController.deviceStream (`_discoveredMachines`, which fills
before the ConnectionManager publishes foundMachines — using only the
latter re-opens a window where the error flashes over live discovery).
Only error kind `adapterOff` is demoted: a genuine
machineConnectFailed while machines are listed still shows the error
view. The adapter view also gains a line telling the user USB keeps
working. `ready` still navigates away regardless.

The preferred machine stays stored per TRANSPORT id
(`connectMachine` saves `machine.deviceId`; serial ids are the
`usb-<vid>-<pid>-<serial>` stable id, not a BLE MAC) — deliberately
un-aliased, so the first wired session ends at the picker and picking
the USB machine once makes later launches auto-connect over the wire.

Tests: scan_flow_ble_off_test (guardian demotion, sticky-error
demotion, connect-in-flight, error copy);
connection_manager_wired_preferred_test locks the per-transport-id
preference flow (first wired session → picker; pick → usb stable id
stored; next launch → auto-connect, no picker).
Doc gate: doc/DeviceManagement.md "Bluetooth-off operation" paragraph.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
bengleUsbIds is deliberately empty — 0x2E8A:0x000A is every default
pico-sdk CDC device, so putting it in the direct-instantiation table
would claim random hobby boards as espresso machines. The pair may only
qualify a port for the v13Model probe (bengleProbeCandidateIds). That
emptiness was documented but untested: someone "completing" the table
later would silently change detection semantics with every existing
test staying green. Pin it, and pin that the default usbDeviceTable
never matches the pair.

Tests: usb_ids_test — bengleUsbIds-stays-empty + no-direct-match cases.
Doc gate: none (test-only; behavior already documented in
doc/DeviceManagement.md and usb_ids.dart).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
On a Bengle (v13Model >= 128) the firmware streams a 28-byte BIG-endian
high-resolution shot sample on an additive characteristic 0xA013 (serial
char 'S') alongside the stock 19-byte 0xA00D sample, both at 15 Hz. It is
a reorganised superset — field order, widths and scaling all differ (e.g.
Weight at offset 20 is U16P5, /32 NOT /100) — so it gets its own pure
decoder rather than reusing the 0xA00D fixed-point parser. The layout is
byte-locked against the contract file (assets/api/bengle_hw_v1.yml,
packet_0xA013) and the de1plus reference decoder.

Why sole source: the frame carries integrated-scale weight (already net
of tare — firmware subtracts LastTARE), gravimetric flow (GFlow) and milk
temp that 0xA00D lacks; consuming both streams would double-sample every
chart. UnifiedDe1 therefore builds two lazy snapshot pipelines and picks
at ACCESS time (currentSnapshot => _isBengle ? _bengleSnapshot :
_de1Snapshot) — picking in a field initialiser would latch the wrong
pipeline for listeners attaching before onConnect completes, and on a
plain DE1 the Bengle pipeline is never built so the 0xA013 subject is
never touched.

Transport asymmetry (deliberate):
- BLE: the CCCD subscribe is gated on the CONFIRMED identity and fired
  from onConnect (first-connect detection block AND the reconnect path —
  reconnect short-circuits before the detection block). Blind-enabling a
  characteristic a plain DE1 lacks throws and permanently stalls the BLE
  command queue (de1plus de1_comms.tcl:777-785). 0xA00D deliberately
  STAYS subscribed on BLE (headroom exists; parse-and-dropped, keeps the
  raw-WS [M] visibility).
- Serial: <+S> is unconditional at connect (no CCCD stall hazard; a DE1
  never emits [S]) because identity isn't known yet and [M] is how the
  serial probe recognises a DE1-family device. Once the identity IS
  confirmed, subscribeBengleShotSample sends <-M> instead (FIX-17.5):
  the firmware serial downlink tops out at ~1920 B/s (16 bytes per
  120 Hz tick, half-duplex) and dual 15 Hz [M]+[S] streams overrun it —
  hw-confirmed 2026-07-09 as truncated/odd-length frames and weight
  flicker.

Truncated (<28 byte) frames are dropped at BOTH layers — the transport
guard protects rxdart internals from a RangeError (seen as fatal on the
0xA00D analogue), the decoder's null return keeps the pure function
total (FIX-11 tail; MTU 517 request landed with the foundation branch).

MachineSnapshot gains additive weight/weightFlow/milkTemperature fields
(default 0.0, fromJson tolerates absent keys so pre-FIX payloads still
decode); steamTemperature stays an int — the fractional 0xA013 value is
round()ed to match the whole-degree 0xA00D field.

Tests: bengle_shot_sample_test (golden frame byte-exact, /32 weight
divergence, big-endian, <28 drop, trailing-bytes, non-zero MilkTemp at
offset 25), bengle_shotsample_pipeline_test (sole-source with 0xA00D
parse-and-dropped, full snapshot field mapping incl. steamTemp rounding,
truncated-frame drop, plain-DE1 must-NOT-subscribe negative),
bengle_shotsample_serial_test (<+S> at connect, [S] routing, truncated
[S] drop, <-S> at disconnect), serial_parity_test FIX-17.5 group (<+M>
still at connect, <-M> from subscribeBengleShotSample),
machine_snapshot_test (fromJson defaults/round-trip/copyWith).
Doc gate: rest_v1.yml + websocket_v1.yml MachineSnapshot schemas gain the
three fields; doc/Api.md /ws/v1/machine/snapshot row updated.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The integrated scale is NOT a separate BLE characteristic: hardware
bring-up proved weight rides the 0xA013 BengleShotSample stream, already
net of tare in firmware (it subtracts LastTARE before serialising — the
same expression its own stop-at-weight logic uses). So:

- IntegratedScaleCapability.initIntegratedScale now listens to the
  transport's guarded bengleShotSample stream and re-emits each valid
  frame as a ScaleSnapshot (batteryLevel 100 — mains-powered sentinel
  that keeps the field non-nullable across the seven scale impls).
  GFlow and milk temp deliberately do NOT ride ScaleSnapshot (no flow
  field; adding one ripples through every scale impl) — they travel on
  MachineSnapshot.weightFlow/milkTemperature from FIX-03. The Flags byte
  is ignored: bit0 is a LastTARE value proxy at best (older firmware
  hardcodes 0), so tare is confirmed by watching the weight.
- The BengleScaleEndpoint null-UUID enum (weight/control) is DROPPED
  along with its placeholder parser/encoder and its two pinning tests:
  it modelled the separate-characteristic design FIX-04 disproved, and
  keeping dead scaffolding upstream invites someone to wire it. A
  comment preserves the "weight rides 0xA013" finding.
- tareIntegratedScale becomes a plain logged no-op (and is test-locked
  to stay OFF the wire): the real ScaleTare MMR write-trigger belongs to
  the stop-at-weight/tare branch (FIX-06). Bridged weights stay correct
  meanwhile because the firmware nets out its own tare state.
- ConnectionManager's post-scan machine policy now runs the scale phase
  against _disconnectSupervisor.latestMachine instead of the stale
  name-picked instance: connectToDe1 may re-resolve the machine class
  from v13Model (FIX-02), and only the re-resolved Bengle instance
  attaches the BengleVirtualScale. The two sibling call sites already
  did this; this aligns the third.

Tests: integrated_scale_capability_test — FIX-04 bridge (golden frame ->
36.5 g, battery sentinel), dispose closes subject, tare no-op stays off
the wire, reconnect lifecycle leak-free; the two BengleScaleEndpoint
null-wire pinning tests are removed with the enum. The demotion-path
capability disposal is already locked controller-level by
de1_controller_resolve_test (foundation branch).
Doc gate: no REST/WS surface change — /api/v1/scale/* and
/ws/v1/scale/snapshot serve the virtual scale unchanged (design D5), and
the MachineSnapshot schema deltas shipped with FIX-03.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The 0xA013 branch changed serial connection behaviour — <+S> is now part
of the continuous-subscription set and subscribeBengleShotSample sends
<-M> once the Bengle identity is confirmed — but the matching
doc/DeviceManagement.md delta did not ride the code commit (the serial
branch deliberately shipped its transport section with no 0xA013
references, leaving these two sentences to this branch). Completing the
doc gate here: the Reads bullet lists the 0xA013 frame among the
continuously-subscribed set, and the Throughput bullet documents the
FIX-17.5 policy (serial-only <-M>; BLE keeps 0xA00D subscribed,
parse-and-dropped) with the hw-confirmed overrun rationale.

Doc-only commit; noted as a doc-gate split from e4b314cb in the PR
draft.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
…timate it

The Bengle computes gravimetric flow on-device, on the load cell it owns, and
ships it in every 15 Hz 0xA013 frame as GFlow. That value already reaches
MachineSnapshot.weightFlow. It did not reach the *scale* surface: ScaleSnapshot
had no flow field, so ScaleController ran its flow estimator over the Bengle's
weight and derived a second, competing flow number -- re-deriving a quantity the
firmware had already computed, from the very signal it computed it from.

The app's estimate is strictly worse than the firmware's. Measured against a
15 Hz pour whose weight climbs at exactly 2.00 g/s, with the firmware reporting
GFlow = 2.00 from the first frame:

  sample (@15 Hz)  |  firmware GFlow  |  app estimate
  1  (~67 ms)      |      2.0000      |     0.0082
  5  (~333 ms)     |      2.0000      |     0.7913
  15 (1.0 s)       |      2.0000      |     1.9382
  59 (3.9 s)       |      2.0000      |     2.0007

The estimator reads ~0 g/s at shot onset and needs about a second to converge on
a number the firmware has correct immediately. The shot path consumes the
estimate, not the firmware's: step-weight exits project on it, the
stopping-yield refinement uses it for cup-removal and settle detection, and it
is what ws/v1/scale/snapshot and the shot record report -- so the two snapshot
surfaces could disagree by 2 g/s at the moment a shot starts.

Add an optional ScaleSnapshot.flow, populate it from GFlow in the 0xA013 bridge,
and have ScaleController pass a device-provided flow through untouched, bypassing
the estimator entirely. Sourcing both surfaces from the same frame is what keeps
them from disagreeing.

Scope: additive and opt-in. flow defaults to null, so every BLE scale keeps the
estimator it has always had -- a scale that reports weight only has no flow of
its own, which is exactly what the estimator is for. The post-tare
flow-suppression window is still honoured on the device-flow path, so the
specced no-spike-after-tare guarantee holds.

The tests assert the pass-through with the Kalman flag ON as well as OFF, and
assert that toggling the flag does not change what a Bengle reports. That is a
regression lock: the estimator choice must stay inert on a device that answers
the question in hardware, whichever estimator becomes the default.
The SAW surface (BengleInterface methods, mixin cache/stream, MockBengle,
the ShotSequencer final-yield bypass, BengleSawBridge, the shotState
machineHasAutonomousSAW flag, and the 'stopAtWeight' capability string)
is already upstream — but the register slot was stubbed (0x00000000,
guessed x10 deci-grams, 500 g clamp), so setStopAtWeightTarget never
reached the wire and the FW never learned the target.

Fill in the firmware truth: EndOfShotWeight (0x00803864, RWD), x100 —
centigrams on the wire, 0 = disable, max 10000 g. The write rides the
shared writeMmrScaled helper, which ROUNDS the scaled value (2.3 g ->
230, not 229 — IEEE-754 2.3*100 == 229.999…), matching de1plus
int(round(weight*100)). The firmware never clamps its Bengle registers
(process_W divides by mult only), so the client-side 0..10000 g clamp
plus the raw max on the enum are the sole guard. getStopAtWeightTarget
now reads the register back (raw x 0.01) and hydrates the stream cache;
production keeps write-precedence (BengleSawBridge's connect-time
re-apply stays the source of truth). BengleScaleMmr.stopAtWeightTarget
is registered in the MMR contract checker per its extension protocol.

Tests: bengle_saw_test rewritten from the stub-pinning group to
byte-exact wire assertions (address/scale/rounding/clamp/disable/
read-back/stream); MockBengle clamp aligned to 10000 g; new handler
test locks 'stopAtWeight' in /machine/capabilities (Bengle yes, plain
DE1 no); new state-manager tests lock machineHasAutonomousSAW == true
on every Bengle shotState frame incl. the idle re-seed (and == false
on a plain DE1).
Doc gate: rest_v1.yml capabilities path description lists the four live
identifiers + the stopAtWeight/targetYield semantics (the schema already
carried them); bengle-integrated-scale e2e scenario refreshed to the
autonomous-SAW reality (workflow targetYield -> SAW MMR, app defers the
final stop, stopReason machineEnded).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
tareIntegratedScale() was a logged no-op awaiting the firmware slot.
Wire it to ScaleTare (0x0080388C, PERM_RWT): a write-trigger whose value
is ignored — we send 1 to match de1plus — that runs an immediate
doLCTare() in firmware. Subsequent 0xA013 Weight arrives already net of
the new zero (firmware serves CurrW - LastTARE), so nothing else in the
weight pipeline changes. The register lives in BengleScaleMmr (owned by
the capability), NOT BengleMmr: the mixin is part of the unified_de1
library, and importing the Bengle-subclass bengle_mmr.dart into it would
invert the import layering (an audited, deliberate divergence from the
original design sketch). Reads of ScaleTare return 0; a tare is
confirmed by watching the weight drop toward 0, never the 0xA013 Flags
bit (a LastTARE value proxy at best; older firmware hardcodes it to 0).

The generic PUT /api/v1/scale/tare surface is deliberately unchanged:
it reaches this trigger through the existing ScaleController ->
BengleVirtualScale.tare() -> tareIntegratedScale() chain, so no new
endpoint and no spec delta are needed. BengleScaleMmr.scaleTare is
registered in the MMR contract checker per its extension protocol.

Tests: integrated_scale_capability_test tare case flipped from the
"stays off the wire" stub pin to the byte-exact FIX-06 frame (exactly
one MMR write: len 4, addr 0x80388C, payload 1 LE).
Doc gate: /api/v1/scale/tare spec + Api.md rows unchanged by design;
bengle-integrated-scale e2e scenario notes the real-hardware tare path.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The Bengle firmware calibrates its integrated scale with a non-blocking
two-point procedure over MMR (ScaleCalCmd/State/Weight 0x00803880/84/88):
precision-zero the empty platform, then latch the SAME known mass on the
LEFT (cmd 4) and RIGHT (cmd 5) halves; a 2x2 solve recovers both per-cell
sensitivities so summed mass is position-independent, then persists. The
app had no way to drive it, so per-unit weight accuracy (and therefore
stop-at-weight) could not be trusted.

- ScaleCalibrationCapability mixin on UnifiedDe1: bounded polling (500 ms
  interval / 30 s deadline vs de1plus's untimed 1 Hz loop), single-flight
  guard, cancellable via a monotonic run token (firmware abort returns to
  Idle, which is NON-terminal - the token unwinds the poll immediately
  and cmd=0 stops the firmware), dispose-safe across a
  disconnect/reconnect (each poll binds its progress subject locally;
  init never resets the token, so a stale poll still sees the bump).
- Completion keys off the packed word's SubState (done=2/error=3), never
  the Step byte: field single-point firmware numbers Complete=4/Error=5
  (colliding with two-point taring/complete), so Step-keyed logic would
  both miss a real completion and mistake an error for success. SubState
  is set atomically with Step in both firmware generations; zero keeps
  working on field firmware.
- A terminal state word is only believed once it is known to belong to
  THIS run. The firmware latches the previous run's terminal word in
  ScaleCalState until it picks up a new command, so a poll racing the
  trigger reads a stale done/error: measured on silicon, a second cal POST
  returned success in 0.316 s while the fresh zero was still running out to
  15.7 s. Benign for a zero, dangerous for the left/right latches - the
  user could lift the reference mass mid-average. _runCalStep therefore
  snapshots the state word before triggering, and accepts a terminal only
  once the state has been observed to leave terminal, or when the terminal
  word differs bitwise from the snapshot (the fresh-word case, for a run
  that legitimately re-terminals inside one poll interval). A run whose
  state never observably changes fails safe on the deadline rather than
  succeeding instantly on the stale word, and stale words are kept off the
  progress stream so a wizard cannot flash "done" right after the trigger.
- The reference weight is read-back-confirmed (0.1 g = one wire LSB at
  x10) before the latch is triggered - a dropped write would calibrate
  to the wrong mass. Firmware reads back whole grams (truncates before
  scaling), so only whole-gram masses round-trip; documented in the spec
  and the hw contract.
- Firmware cmd 3 (tare) is deliberately excluded - reaprime tares via
  the dedicated ScaleTare register (FIX-06). cmd 2 is the removed
  single-cell auto-detect and must not be resurrected.
- REST: POST /api/v1/machine/scale/calibrate (zero|left|right|abort;
  200-with-success:false for failed runs - outcome is data, transport is
  HTTP; 202 abort; 400 incl. a non-object-body guard; 404 on plain DE1)
  plus the 'scaleCalibration' capability string.
- Demotion teardown in De1Controller now disposes this third capability
  (the previous shape would leak the cal subjects on a demoted interim)
  and the controller-level resolve test locks it.
- BengleCalMmr registered in the bengle_hw_v1.yml contract checker.

Tests: scale_calibration_capability_test (incl. the single-point
SubState-terminal byte anchors 0x04020000/0x05030000, the order-free
left-latch-accepts-ok case, and the stale-terminal race group),
de1handler_scale_calibrate_test (12, incl. no-machine 500), MockBengle cal
group, resolve-test demotion lock, contract-checker rows.
Doc gate: rest_v1.yml (calibrate path + 2 schemas + capabilities
enum/example/descriptions), doc/Api.md rows, new e2e scenario
bengle-scale-calibration.md + refreshed capabilities array in
bengle-integrated-scale.md. No websocket_v1.yml / DeviceManagement.md
delta.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The LedStripCapability on main was a stub (BengleLedEndpoint null wires):
setLedStrip/commit/reset cached but never touched the machine. The firmware
wire spec has since shipped — six PERM_RWD registers holding packed
0x00RRGGBB int32 (LE on the wire): palettes FrontLEDAwake 0x00803898 /
RearLEDAwake 0x0080389C / FrontLEDSleep 0x008038A0 / RearLEDSleep 0x008038A4
(FW auto-applies on sleep/wake, and immediately when written while already
in that state) and live colours FrontLEDColor 0x00803890 / RearLEDColor
0x00803894.

- BengleLedMmr replaces the stub. setLedStrip writes the four palette
  registers byte-exactly (16-bit app channels map down by high byte);
  resetLedStrip reads them back (8→16 byte-replication, lossless for 8-bit
  sources). No switch register exists — FW mirrors the switch from the
  front strip, so frontSwitch stays JSON-only (ignored on write, mirrors
  front on read).
- Palette writes already persist (PERM_RWD); there is no NVM-commit
  register. commitLedStrip() re-asserts the cache (kept for API symmetry —
  Streamline's Save calls it, the REST contract promises 202); reset is a
  4-register read-back. rest_v1.yml / doc/Api.md / interface doc comments
  reworded from the old NVM-latch model; commit/reset requestBody is now
  optional (body ignored).
- New previewLedColor/clearLedPreview + POST /api/v1/machine/ledStrip/
  preview and /preview/clear: show a colour now, regardless of awake/sleep,
  without touching the stored palette or the cache; clear restores the
  cached awake pair. Both routes gated `is! BengleInterface → 404`,
  defensive body parsing (non-map → 400, malformed colours → black).
- The cache is hydrated from the machine on connect. GET
  /api/v1/machine/ledStrip serves the in-memory cache, so without hydration
  a fresh connect serves an all-off palette while the firmware is holding
  real stored colours — after an app restart the Lighting page would show
  both awake and asleep as off. initLedStrip() therefore reads the four
  stored palette registers and seeds the cache, so the first GET serves the
  machine's real colours.
  Eager-on-connect rather than lazy-on-first-GET: it puts no latency on the
  Lighting page's first paint (on firmware without the LED registers, a lazy
  read would pay the 4 s x 3 read-timeout ladder there), and connect already
  performs failure-tolerant MMR warm-ups plus six identity reads, so four
  more amortise where reads already happen. It also means clearLedPreview
  restores the machine's real awake palette rather than black after a fresh
  connect.
  Hydration is read-only and failure-tolerant: it reuses the reset path's
  _readLedStrip() (the four palette registers only — the live/preview pair
  0x00803890/94 is never touched, so it cannot disturb a preview or flash
  the strips), and a failed read logs a warning, leaves the cache all-off,
  and never fails the connect. PUTs overwrite the cache exactly as before.
- LED writes use _mmrWriteRaw/_packMMRInt on purpose: raw packed int32,
  app min/max null, FW clamps to 0x00FFFFFF — writeMmrScaled's rounding
  semantics don't apply to colour bits.
- BengleLedMmr registered in the MMR contract checker against
  bengle_hw_v1.yml rows 43-48. The LED block moved wholesale in the FW
  "additive renumber" (d9e1801e) — pre-renumber addresses write the wrong
  registers; the checker is what catches that drift class.

This wiring was hardware-validated on a live Bengle against firmware
build 90 over both BLE and USB serial; the byte-exact capability tests
lock the verified frames.

The Streamline skin needs no change: renderLedSettings() already fetches
via getLedStrip() on first Lighting page entry and paints from the
response, so it shows the stored palette.

Tests: led_strip_capability_test (byte-exact palette/preview frames, 16↔8
mapping, cache semantics, lifecycle, connect-time hydration byte-exact for
all four palettes, a wire-level read-only negative — no write frame to any
LED register, zero traffic of any kind to the live/preview pair, exactly one
read per palette register — and a failed-read fallback via a transport that
rejects LED reads), de1handler_led_strip_test (preview REST incl. 400/404
gating, GET-after-hydration over a real Bengle on the fake transport),
mock_bengle_led_test, mmr_contract_test (+6 LED rows).
FakeBleTransport.queueOnConnectResponses() now queues the four palette
registers (default 0) so every existing Bengle connect test hydrates.
Doc gate: rest_v1.yml preview paths + PERM_RWD rewording; doc/Api.md rows;
bengle-led-strip scenario refreshed (sb-dev style, preview steps).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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