# Phase 11: Synthesis and Config Layer - Context

**Gathered:** 2026-03-27
**Status:** Ready for planning

<domain>
## Phase Boundary

Add ClassFreqConfigs entries for all 18 new classes in AllClasses() plus 3 LDAP/Kerberos/Syslog classes (adding them to AllClasses() too). Update `PrintConfig` to output classes grouped by family with section header comments. Add `[groups]` TOML config support for users to reassign protocols to different sound families. Fix all broken synth/config tests.

</domain>

<decisions>
## Implementation Decisions

### ClassFreqConfigs Entries
- **D-01:** Add ClassFreqConfigs entries for all 18 new classes currently in AllClasses(). Use Hz values, waveforms, pans, and groups from the Phase 9 frequency allocation table comment in `synth/config.go` lines 74-110. Use `WaveformPresetHarmonics()` for all new entries (not hand-tuned harmonics).
- **D-02:** Add ClassLDAP, ClassKerberos, ClassSyslog to AllClasses() in `classify/types.go`. Create ClassFreqConfigs entries for them using `autoAssignFreq`-derived Hz values (FNV hash in [2500, 4000] Hz range). Their group is "Infrastructure", waveform is Triangle (matching the Infrastructure family pattern).
- **D-03:** After D-01 and D-02, AllClasses() returns 35 entries (32 + 3). TestAllClassesCount updated to 35.

### PrintConfig Group Headers (GRP-02)
- **D-04:** PrintConfig groups classes by their Group field value. Each group gets a comment header line: `# <Group>` followed by a blank line, then all classes in that group. Groups are ordered: Infrastructure, Web, Mail, Remote Access, File Transfer, Database, Discovery, VoIP, Unknown.
- **D-05:** Within each group, classes are ordered by ascending BaseHz (matching the frequency allocation table order).
- **D-06:** User-defined classes (not in AllClasses but in FreqCfgs) are emitted after all built-in groups under a "# User-defined" section header.

### TOML Groups Config (GRP-03)
- **D-07:** Users define group reassignments in TOML with a `[groups]` table using simple key-value pairs: `IMAP = "Web"` reassigns IMAP from Mail to Web group. The key is the TrafficClass string value, the value is the target group name.
- **D-08:** Group reassignment only affects `--print-config` output grouping and the Group field in FreqConfig. It does NOT change frequency, waveform, or pan — those stay as designed. PrintConfig reflects the reassignment.
- **D-09:** Unknown group names in `[groups]` config are accepted (user can invent custom group names). Unknown class names produce a warning (same pattern as `[sounds.X]` with unknown class).

### Claude's Discretion
- Exact Hz values for LDAP, Kerberos, Syslog (computed from autoAssignFreq FNV hash)
- Pan positions for LDAP, Kerberos, Syslog
- Test structure for new ClassFreqConfigs entries and PrintConfig group output
- Whether to add `[groups]` to rawConfig struct as `map[string]string` or a custom type
- How to handle group reassignment in the merge/load pipeline

### Folded Todos
- **"Expand Traffic Classes"** (from `.planning/todos/pending/001-expand-traffic-classes.md`) — Phase 11 completes the synthesis side of this request. Constants/rules were added in Phase 10; now all classes get sound configurations.

</decisions>

<canonical_refs>
## Canonical References

**Downstream agents MUST read these before planning or implementing.**

### Synth Package (primary modification target)
- `synth/config.go` — `ClassFreqConfigs` map (add 21 new entries), frequency allocation table comment (lines 74-110), `FreqConfig` struct, `WaveformPresetHarmonics` function
- `synth/config_test.go` — `TestAllClassesHaveConfig`, `TestClassFreqConfigsMatchAllClasses`, `TestFrequenciesInRange`, `TestFrequenciesUnique`, `TestNewBankHas14Layers`

### Config Package (PrintConfig + groups)
- `config/config.go` — `PrintConfig` function (lines 270-336), `rawConfig` struct (line 38-41), `LoadResult` struct, `merge` function, `autoAssignFreq` function, `addAutoFreqEntries`
- `config/config_test.go` — `TestLoadAllDefaultsPresent`, `TestPrintConfigOutput`

### Classification Package (AllClasses update)
- `classify/types.go` — AllClasses() function, TrafficClass constants (add LDAP/Kerberos/Syslog to AllClasses())
- `classify/classifier_test.go` — `TestAllClassesCount` (update from 32 to 35)

### Requirements
- `.planning/REQUIREMENTS.md` — GRP-02, GRP-03
- `.planning/ROADMAP.md` — Phase 11 success criteria

### Prior Phase Context
- `.planning/phases/09-frequency-design-and-group-architecture/09-CONTEXT.md` — Frequency design decisions, waveform-per-family strategy
- `.planning/phases/10-classification-layer/10-CONTEXT.md` — PROTO-08 frequency strategy (D-01: autoAssignFreq for LDAP/Kerberos/Syslog)

</canonical_refs>

<code_context>
## Existing Code Insights

### Reusable Assets
- `WaveformPresetHarmonics(wt, baseHz, sampleRate)` — generates harmonics for any waveform at any frequency; use for all 21 new ClassFreqConfigs entries
- `autoAssignFreq(className)` — FNV hash into [2500, 4000] Hz; use for LDAP/Kerberos/Syslog Hz values
- `classAnnotation(cls, cfg, autoClasses)` — already handles "default", "override", "auto-assigned" annotations
- `copyDefaults()` and `merge()` — existing config merge pipeline to extend with group support

### Established Patterns
- ClassFreqConfigs entries follow: `classify.ClassX: {BaseHz, WaveformType, Harmonics: WaveformPresetHarmonics(...), Pan, Group}` pattern
- PrintConfig iterates AllClasses() for built-ins, then sorts user-defined separately
- rawConfig uses TOML struct tags for decoding; adding `[groups]` follows same pattern
- SoundOverride uses pointer fields for partial overrides

### Integration Points
- `config.Load()` returns `LoadResult` with `FreqCfgs` map — group reassignments must be applied before returning
- `PrintConfig` reads `FreqCfgs` and `AllClasses()` — group headers derived from `FreqConfig.Group` field
- `NewBank()` in `synth/bank.go` creates layers from `ClassFreqConfigs` — all new entries will get synthesis layers automatically
- `TestNewBankHas14Layers` in `synth/bank_test.go` — name is stale, needs update to reflect 35 classes

</code_context>

<specifics>
## Specific Ideas

- The frequency allocation table comment in `synth/config.go` (lines 74-110) is the authoritative source for all Hz, waveform, group, and pan values for the 18 table-designed classes
- LDAP/Kerberos/Syslog get Infrastructure group + Triangle waveform (matching existing Infrastructure family) but their Hz comes from autoAssignFreq, not the table
- PrintConfig currently has no group awareness — it just lists all classes in AllClasses() order. The refactor adds group-based iteration with comment headers
- `go test ./...` must pass fully after Phase 11 — this is the first time since Phase 10 that the full test suite should be green

</specifics>

<deferred>
## Deferred Ideas

None — discussion stayed within phase scope.

</deferred>

---

*Phase: 11-synthesis-and-config-layer*
*Context gathered: 2026-03-27*