---
phase: 06-config-package-and-sound-overrides
plan: 02
subsystem: cmd/encode
tags: [cli, config, RunSynthesis, dependency-injection, cobra]

# Dependency graph
requires:
  - phase: 06-01
    provides: config.Load(configPath string) returns map[classify.TrafficClass]synth.FreqConfig
  - phase: 05-waveform-types-and-bank-decoupling
    provides: NewBank(tau, cfgs) with injected config map, FreqConfig.WaveformType

provides:
  - --config flag in CLI (CFG-03)
  - config.Load called at startup before capture (D-11 fail fast)
  - RunSynthesis(snapshots, outputPath, freqCfgs) with injected config map (D-10)
  - Merged config flows end-to-end: TOML file -> config.Load -> RunSynthesis -> NewBank

affects:
  - encode/mp3.go (RunSynthesis signature changed)
  - cmd/netsynth/main.go (--config flag, config.Load, pass freqCfgs through pipeline)

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Dependency injection: config map flows from main() through runLiveMode/runPcapMode to RunSynthesis to NewBank"
    - "Fail-fast config loading: config.Load called after BPF validation, before capture starts (D-11)"
    - "Explicit configPath string var for --config flag, empty string triggers auto-discovery"

key-files:
  created: []
  modified:
    - encode/mp3.go
    - encode/mp3_test.go
    - cmd/netsynth/main.go

key-decisions:
  - "Option A for freqCfgs propagation: pass as parameter to runLiveMode/runPcapMode rather than package-level var — explicit data flow, easier to test"
  - "config.Load called before output path resolution — config errors abort before any state changes"

patterns-established:
  - "Config map injected at call boundary (main -> run -> runLiveMode/runPcapMode -> RunSynthesis -> NewBank)"

requirements-completed: [CFG-03]

# Metrics
duration: 2min
completed: 2026-03-26
---

# Phase 6 Plan 02: CLI Config Wiring Summary

**--config flag added to Cobra, config.Load wired at startup, RunSynthesis signature changed to accept injected freqCfgs map — end-to-end config flow from TOML file to synthesis**

## Performance

- **Duration:** ~2 min
- **Started:** 2026-03-26T20:01:59Z
- **Completed:** 2026-03-26T20:04:27Z
- **Tasks:** 2
- **Files modified:** 3 (encode/mp3.go, encode/mp3_test.go, cmd/netsynth/main.go)

## Accomplishments

- Changed `RunSynthesis` third parameter: accepts `freqCfgs map[classify.TrafficClass]synth.FreqConfig` (D-10)
- Updated all 3 RunSynthesis call sites in encode tests to pass `synth.ClassFreqConfigs`
- Added `configPath string` var and `--config` flag registration in Cobra (CFG-03)
- Imported `config` and `synth` packages into cmd/netsynth/main.go
- Wired `config.Load(configPath)` into `run()` after BPF validation, before capture (D-11)
- Changed `runLiveMode` and `runPcapMode` signatures to accept `freqCfgs` parameter
- Updated both `encode.RunSynthesis` call sites to pass `freqCfgs`
- Full test suite passes: 7 packages, all green

## Task Commits

1. **Task 1** - `3dfcbbe` feat(06-02): add freqCfgs parameter to RunSynthesis
2. **Task 2** - `413cceb` feat(06-02): wire --config flag and config.Load into CLI pipeline

## Files Created/Modified

- `encode/mp3.go` - RunSynthesis now accepts `freqCfgs map[classify.TrafficClass]synth.FreqConfig`; uses `freqCfgs` in `synth.NewBank(1.0, freqCfgs)` call
- `encode/mp3_test.go` - Updated 3 RunSynthesis calls to pass `synth.ClassFreqConfigs` as third arg
- `cmd/netsynth/main.go` - `configPath` var, `--config` flag, `config` and `synth` imports, `config.Load` call, updated function signatures, updated RunSynthesis calls

## Decisions Made

- **Option A for freqCfgs propagation**: Pass config map as function parameter to `runLiveMode`/`runPcapMode` rather than storing in a package-level variable. Cleaner data flow, functions remain testable in isolation.
- **config.Load position in run()**: Called after BPF filter validation, before output path resolution and capture start. Config errors abort immediately before any I/O begins (D-11).

## Deviations from Plan

None - plan executed exactly as written. The worktree required a rebase onto local master to include phase 05 bank-decoupling code (NewBank 2-arg signature) and phase 06-01 config package before implementation could begin — this is expected prerequisite resolution, not a deviation.

## Issues Encountered

- Worktree was based on origin/master (commit 41e2278, pre-phase-05). Rebased onto local master (936aeea) to get WaveformType, 2-arg NewBank, and config package. No code conflicts.

## User Setup Required

None.

## Next Phase Readiness

- Full end-to-end config flow is wired: user creates netsynth.toml -> `--config` passes path -> `config.Load` merges -> `RunSynthesis` uses merged map -> `NewBank` synthesizes with custom frequencies/waveforms
- Phase 06-03 (if any) can build on this wired pipeline for additional config features

## Self-Check: PASSED

- FOUND: encode/mp3.go — contains `func RunSynthesis(snapshots []classify.WindowSnapshot, outputPath string, freqCfgs map[classify.TrafficClass]synth.FreqConfig) error`
- FOUND: encode/mp3_test.go — contains `RunSynthesis(snaps, tmpPath, synth.ClassFreqConfigs)`
- FOUND: cmd/netsynth/main.go — contains `configPath string`, `config.Load(configPath)`, `runLiveMode(cmd, freqCfgs)`
- FOUND: 3dfcbbe (Task 1 commit)
- FOUND: 413cceb (Task 2 commit)

---
*Phase: 06-config-package-and-sound-overrides*
*Completed: 2026-03-26*