---
phase: 11-synthesis-and-config-layer
verified: 2026-03-27T15:41:00Z
status: human_needed
score: 11/11 must-haves verified
human_verification:
  - test: "Run `go build -o /tmp/netsynth . && /tmp/netsynth --print-config | head -5` and listen to an output MP3 generated with mixed traffic types"
    expected: "Each traffic class group (Infrastructure, Web, Mail, etc.) produces a perceptually distinct timbre — Triangle waveforms sound softer/bell-like vs Square waveforms (buzzy/hollow) vs Sawtooth (bright/reedy) vs Sine (pure tone)"
    why_human: "Perceptual audio quality and family coherence ('distinct, family-coherent sound') requires a human listening test; automated tests only verify Hz/waveform parameters and group metadata, not the sonic result"
---

# Phase 11: Synthesis and Config Layer Verification Report

**Phase Goal:** Every new traffic class produces a distinct, family-coherent sound and --print-config shows all classes organized by group with section headers
**Verified:** 2026-03-27T15:41:00Z
**Status:** human_needed (all automated checks pass; perceptual audio quality requires human listening test)
**Re-verification:** No — initial verification

## Goal Achievement

### Observable Truths

| # | Truth | Status | Evidence |
|---|-------|--------|---------|
| 1 | ClassFreqConfigs has exactly 35 entries matching AllClasses() | VERIFIED | `grep -c "classify\.Class" synth/config.go` = 35; `--print-config` emits 35 `[sounds.*]` entries; TestAllClassesCount passes with `want 35` |
| 2 | Every new class has correct Hz, waveform, pan, and group from frequency allocation table | VERIFIED | All 21 new entries confirmed in synth/config.go (lines 168-369) with exact Hz, WaveformType, Pan, Group values matching the plan spec; `go test ./synth/...` passes |
| 3 | LDAP, Kerberos, Syslog appear in AllClasses() and have Infrastructure group with Triangle waveform | VERIFIED | classify/types.go line 69: `ClassLDAP, ClassKerberos, ClassSyslog` in AllClasses(); synth/config.go lines 349-369: all three have `WaveformType: WaveformTriangle` and `Group: "Infrastructure"` |
| 4 | go test ./synth/... ./classify/... ./config/... all pass | VERIFIED | `go test ./...` all 7 packages pass (confirmed by fresh run) |
| 5 | PrintConfig output groups classes by family with section header comments | VERIFIED | `--print-config` binary output shows `# Infrastructure`, `# Web`, `# Mail`, `# Remote Access`, `# File Transfer`, `# Database`, `# VoIP`, `# Unknown` headers in canonical order |
| 6 | Groups appear in canonical order: Infrastructure, Web, Mail, Remote Access, File Transfer, Database, Discovery, VoIP, Unknown | VERIFIED | TestPrintConfigGroupHeaders passes; binary spot-check confirms order matches groupOrder slice in config.go line 284 |
| 7 | Within each group, classes are sorted by ascending BaseHz | VERIFIED | PrintConfig spot-check output shows ascending Hz within each group (e.g., Infrastructure: 65, 73, 82, 93, 105, 118, 133, 2950, 3050, 3250); sort.Slice by BaseHz confirmed in config.go lines 334-339 |
| 8 | User-defined classes appear under a User-defined section header after all built-in groups | VERIFIED | config.go lines 399-419 emit `# User-defined` section; `# User-defined` string present in source |
| 9 | Users can define [groups] in TOML to reassign a class to a different group | VERIFIED | TestLoadGroupOverride and TestPrintConfigGroupReassignment both pass; applyGroupOverrides called in Load() at line 103 after merge() |
| 10 | Unknown class names in [groups] produce a warning, not an error | VERIFIED | TestLoadGroupUnknownClass passes; test output shows `Warning: config: [groups]: unknown class "BOGUS" (ignored)` on stderr |
| 11 | Group reassignment only affects PrintConfig grouping, not frequency or waveform | VERIFIED | TestLoadGroupOverride asserts `cfg.BaseHz == defaultCfg.BaseHz` (unchanged); applyGroupOverrides only mutates `cfg.Group`, not BaseHz or WaveformType |

**Score:** 11/11 truths verified (automated); 1 truth requires human verification (perceptual audio quality)

### Required Artifacts

| Artifact | Expected | Status | Details |
|----------|----------|--------|---------|
| `synth/config.go` | 21 new ClassFreqConfigs entries | VERIFIED | 35 total entries; all 21 new classes present with correct values per allocation table |
| `classify/types.go` | AllClasses() returns 35 entries including LDAP/Kerberos/Syslog | VERIFIED | 35-entry return slice; LDAP/Kerberos/Syslog added to Infrastructure section at line 69 |
| `config/config.go` | Group-ordered PrintConfig, [groups] TOML support, applyGroupOverrides function | VERIFIED | groupOrder slice (line 284), applyGroupOverrides function (line 270), rawConfig.Groups field (line 41), called in Load() (line 103) |
| `config/config_test.go` | Tests for group headers, group reassignment, unknown class warning | VERIFIED | 4 new test functions at lines 605-692: TestPrintConfigGroupHeaders, TestLoadGroupOverride, TestLoadGroupUnknownClass, TestPrintConfigGroupReassignment — all pass |

### Key Link Verification

| From | To | Via | Status | Details |
|------|----|-----|--------|---------|
| `config/config.go` | `synth/config.go` | PrintConfig reads FreqConfig.Group field | WIRED | `cfg.Group` used at lines 329, 364; FreqConfig.Group drives group bucketing in builtinByGroup map |
| `config/config.go` | `classify/types.go` | PrintConfig iterates AllClasses() and groups by Group field | WIRED | `classify.AllClasses()` called at lines 326 and 362; iteration drives builtinByGroup construction and customGroups scan |
| `synth/config.go` | `classify/types.go` | ClassFreqConfigs references TrafficClass constants | WIRED | All 35 map keys use `classify.Class*` constants; pattern `classify\.Class(IMAP|POP3|...)` confirmed present |

### Data-Flow Trace (Level 4)

| Artifact | Data Variable | Source | Produces Real Data | Status |
|----------|---------------|--------|--------------------|--------|
| `config/config.go PrintConfig` | `builtinByGroup` | `classify.AllClasses()` + `result.FreqCfgs[cls]` | Yes — 35 real entries from copyDefaults() which copies synth.ClassFreqConfigs | FLOWING |
| `config/config.go PrintConfig` | `result.FreqCfgs` | `Load()` → `copyDefaults()` → `merge()` → `applyGroupOverrides()` | Yes — real map with 35 entries, plus any user overrides applied | FLOWING |

### Behavioral Spot-Checks

| Behavior | Command | Result | Status |
|----------|---------|--------|--------|
| --print-config emits group headers | `/tmp/netsynth_test --print-config \| grep "^# [A-Z]"` | Infrastructure, Web, Mail, Remote Access, File Transfer, Database, VoIP, Unknown all present | PASS |
| 35 sound entries emitted | `/tmp/netsynth_test --print-config \| grep "^\[sounds\." \| wc -l` | 35 | PASS |
| Classes sorted ascending within group | Infrastructure group: 65, 73, 82, 93, 105, 118, 133, 2950, 3050, 3250 Hz | Correct ascending order | PASS |
| go test ./... passes all packages | `go test ./...` | 7 packages ok | PASS |
| Perceptual audio quality | Requires listening to generated MP3 | Cannot verify programmatically | SKIP (human_needed) |

### Requirements Coverage

| Requirement | Source Plan | Description | Status | Evidence |
|-------------|------------|-------------|--------|---------|
| GRP-02 | 11-01-PLAN.md, 11-02-PLAN.md | `--print-config` output organizes classes by group with section headers | SATISFIED | TestPrintConfigGroupHeaders passes; binary spot-check confirms group headers in canonical order; config.go groupOrder drives emission order |
| GRP-03 | 11-01-PLAN.md, 11-02-PLAN.md | Users can define `[groups]` in TOML config to reassign protocols to different sound families | SATISFIED | rawConfig.Groups field parses `[groups]` TOML; applyGroupOverrides wired into Load(); TestLoadGroupOverride and TestPrintConfigGroupReassignment both pass |

No orphaned requirements — both GRP-02 and GRP-03 are claimed by both plans and satisfied by implementation.

### Anti-Patterns Found

| File | Line | Pattern | Severity | Impact |
|------|------|---------|----------|--------|
| None found | — | — | — | — |

No TODO/FIXME/placeholder comments, no empty handlers, no stub return values in phase-modified files. The `return []HarmonicDef{{Ratio: 1, Amplitude: 1.0}}` in WaveformSine case is the legitimate single-harmonic definition, not a stub.

Hardcoded count audit:
- `grep "want 14" config/config_test.go` — no matches
- `grep "want 32" classify/classifier_test.go` — no matches
- `grep "!= 14" synth/bank_test.go` — no matches
- TestNewBankHas14Layers renamed to TestNewBankHasAllLayers

### Human Verification Required

#### 1. Perceptual Audio Quality — Family-Coherent Distinct Sounds

**Test:** Build the binary (`go build -o /tmp/netsynth .`), run it against a live interface or a pcap file, and listen to the output MP3. Alternatively, generate a test clip exercising multiple classes using a synthetic pcap.

**Expected:** Traffic classes within the same family share a recognizable waveform timbre:
- Infrastructure classes (ICMP, DNS, DHCP, LDAP, etc.) — gentle bell-like quality from Triangle waveform
- Remote Access and File Transfer classes (SSH, RDP, FTP, SMB, etc.) — buzzy/hollow timbre from Square waveform
- Database classes (MySQL, PostgreSQL, Redis, MongoDB) — bright/reedy timbre from Sawtooth waveform
- SIP (VoIP) — pure clean tone from Sine waveform
- Different families should sound clearly distinct from one another while classes within a family are recognizably related

**Why human:** Perceptual audio quality (timbre coherence, distinctness under real traffic loads, absence of clashing frequencies) cannot be verified programmatically. The code correctly implements the waveform types and Hz values, but whether the resulting sound is perceptually "family-coherent" as described in the phase goal requires a human ears-on test.

### Gaps Summary

No gaps. All automated must-haves pass. The only pending item is a human listening test for perceptual audio quality (Success Criterion 2 from the phase scope, flagged at verification request time).

**Commit trail verified:**
- `1556ce8` — feat(11-01): add 21 ClassFreqConfigs entries and include LDAP/Kerberos/Syslog in AllClasses()
- `35d8915` — fix(11-01): update hardcoded count assertions to reflect 35 traffic classes
- `374282e` — feat(11-02): add [groups] TOML support and group-ordered PrintConfig
- `7bf3ea1` — test(11-02): add group header and reassignment tests (GRP-02, GRP-03)

---

_Verified: 2026-03-27T15:41:00Z_
_Verifier: Claude (gsd-verifier)_