diff --git a/.planning/phases/04-usb-manager-label-printing/04-01-SUMMARY.md b/.planning/phases/04-usb-manager-label-printing/04-01-SUMMARY.md
new file mode 100644
index 0000000..346baac
--- /dev/null
+++ b/.planning/phases/04-usb-manager-label-printing/04-01-SUMMARY.md
@@ -0,0 +1,110 @@
+---
+phase: 04-usb-manager-label-printing
+plan: "01"
+subsystem: usb
+tags: [usb, serial, goroutine, enumeration, reconnect]
+dependency_graph:
+  requires: []
+  provides: [internal/usb package, USBManager, DeviceSpec, DeviceEvent, Command]
+  affects: [internal/api/router.go (future SSE integration), main.go (future Manager.Start call)]
+tech_stack:
+  added: [go.bug.st/serial v1.6.4, github.com/creack/goselect v0.1.2]
+  patterns: [goroutine-per-device, context+done-channel teardown, injectable test seams]
+key_files:
+  created:
+    - internal/usb/device.go
+    - internal/usb/enumerate.go
+    - internal/usb/manager.go
+    - internal/usb/device_test.go
+    - internal/usb/manager_test.go
+    - internal/usb/mock_port_test.go
+  modified:
+    - go.mod
+    - go.sum
+decisions:
+  - "VID/PID enumeration via system_profiler SPUSBDataType JSON + injectable sysProfilerCmd for tests; gracefully returns empty map on Linux/CI"
+  - "serialPort interface abstraction allows test injection via noopSerialOpener without hardware"
+  - "mockPort.Read() blocks on closeCh channel until Close() is called — mirrors real blocking serial Read behavior"
+  - "Read buffer capped at 4096 bytes per T-04-01 threat mitigation before forwarding to command handler"
+  - "pollInterval injected at newManagerForTest level (20ms in tests vs 2s default) for fast deterministic cycling"
+metrics:
+  duration_minutes: 15
+  completed_date: "2026-04-10"
+  tasks_completed: 2
+  tasks_total: 2
+  files_created: 6
+  files_modified: 2
+---
+
+# Phase 4 Plan 01: USB Manager Summary
+
+**One-liner:** Goroutine-per-device USB Manager with VID/PID enumeration via system_profiler, context+done-channel teardown, and injectable test seams — no hardware required for testing.
+
+## What Was Built
+
+### internal/usb/device.go
+Core types: `DeviceSpec`, `DeviceRole`, `DeviceState`, `DeviceEvent`, `Command`, `CommandType`. `KnownDevices` registry maps `"VID:PID"` to `DeviceSpec` (PRT Qutie placeholder `0525:a4a7`). `ParseVIDPID()` helper with error on malformed input.
+
+### internal/usb/enumerate.go
+`enumerateConnected()` shells out to `system_profiler SPUSBDataType -json`, parses the USB device tree, normalises hex IDs (strips `0x` prefix, lowercases), and cross-references with `serial.GetPortsList()` to return `map[VIDPID]portPath` containing only `KnownDevices` entries. Two injectable function vars (`sysProfilerCmd`, `serialPortsListCmd`) enable hermetic unit tests. Returns empty map with no error on Linux/CI (graceful degradation when `system_profiler` is unavailable).
+
+### internal/usb/manager.go
+`Manager` owns all device goroutines. Poll loop calls `enumerateFunc()` every `pollInterval`, reconciles prev/current snapshots, spawns/stops `deviceLoop` goroutines. `deviceLoop` opens the serial port, runs an inner read goroutine (exits on `ctx.Done()` or port error), and handles `CmdWrite`/`CmdClose` commands. Goroutine teardown: child context cancelled → `port.Close()` called → read goroutine unblocked → `done` channel closed → poll loop proceeds. `ErrDeviceNotConnected` returned by `Send()` when device absent.
+
+### Threat mitigations applied
+- **T-04-01**: Read buffer capped at 4096 bytes in `deviceLoop` before forwarding to command handler.
+
+## Commits
+
+| Task | Commit  | Description |
+|------|---------|-------------|
+| Task 1 | f5b1d31 | USB device types, KnownDevices registry, VID/PID enumeration |
+| Task 2 | 82eaf6b | USB Manager goroutine-per-device, poll loop, reconnect, leak-safe teardown |
+
+## Test Results
+
+```
+=== RUN   TestKnownDevicesContainsPRTQutie      PASS
+=== RUN   TestEnumerateConnectedMockOutput       PASS
+=== RUN   TestDeviceSpecString                   PASS
+=== RUN   TestParseVIDPIDValid                   PASS
+=== RUN   TestParseVIDPIDInvalid                 PASS
+=== RUN   TestManagerStartSpawnsOneGoroutine     PASS
+=== RUN   TestManagerDisconnectReconnectEvents   PASS
+=== RUN   TestManagerStopGoroutineLeak           PASS
+=== RUN   TestManagerSendToAbsentDevice          PASS
+=== RUN   TestGoroutineStability                 PASS
+PASS (race detector clean, 30s timeout)
+```
+
+## Deviations from Plan
+
+### Auto-fixed Issues
+
+None — plan executed exactly as written.
+
+### Additional Files
+
+`internal/usb/mock_port_test.go` was added (not listed in plan's `files_modified`). The plan referenced `newMockPort()` in the test action spec but did not create a dedicated file for it — the mock helper needed to be in a separate `_test.go` file to avoid shipping test infrastructure in the production binary.
+
+## Known Stubs
+
+| File | Item | Reason |
+|------|------|--------|
+| internal/usb/device.go | `KnownDevices["0525:a4a7"]` VID/PID placeholder | Real VID/PID unknown until hardware arrives 2026-04-13 — update after characterization |
+| internal/usb/manager.go | Read bytes in `deviceLoop` are logged but not forwarded | No upstream consumer yet; Phase 4 plan 03 (printer driver) will consume read events |
+
+## Threat Flags
+
+None — no new network endpoints, auth paths, or schema changes introduced. USB serial I/O is local-only per T-04-03 acceptance.
+
+## Self-Check: PASSED
+
+- internal/usb/device.go: FOUND
+- internal/usb/enumerate.go: FOUND
+- internal/usb/manager.go: FOUND
+- internal/usb/device_test.go: FOUND
+- internal/usb/manager_test.go: FOUND
+- internal/usb/mock_port_test.go: FOUND
+- Commit f5b1d31: FOUND
+- Commit 82eaf6b: FOUND