c2
A TUI-based command-and-control app for interacting with LLMs, bootstrapped from lore. c2 adds a voice layer — you can speak to it, and it speaks back. Meta-commands ("replay that", "switch topic", "stop") are recognised locally without hitting the LLM.
Features
- Voice + text input — speak or type, switch modes with Tab
- Full voice pipeline — keyword wake word (KWS) → VAD → STT → command recognition or LLM
- TTS readout — Kokoro (neural) or macOS
say backend
- Resource viewer — full-screen in-app overlay with TTS playback from cursor position
- Topics, profiles, system prompts, resources, stats
- Self-contained — all data and config stored in
~/.c2/
Installation
Prerequisites
- Go 1.22+
- macOS (audio via PortAudio; sherpa-onnx ships macOS-only binaries)
portaudio headers (brew install portaudio)
Build
git clone https://github.com/jrniemiec/c2
cd c2
make build # builds to ./bin/c2
make install # builds + installs to ~/dev/bin/c2 (with codesign)
Never use bare go build — always go through make.
Configuration
All configuration and data live under ~/.c2/.
Config file location
~/.c2/config.json main config (LLM profiles + voice settings)
~/.c2/debug.log voice pipeline debug log
c2 config section
The config file contains LLM profile settings and a "c2" section for voice/audio. Example:
{
"profile": "...",
"c2": {
"tts_backend": "kokoro",
"tts_model": "/path/to/kokoro/model.onnx",
"tts_voices": "/path/to/kokoro/voices.bin",
"tts_tokens": "/path/to/kokoro/tokens.txt",
"tts_data_dir": "/path/to/espeak-ng-data",
"tts_lexicon": "",
"tts_voice": "en-us",
"tts_speaker_id": 0,
"tts_speed": 1.0,
"vad_model": "/path/to/silero_vad.onnx",
"stt_encoder": "/path/to/encoder.int8.onnx",
"stt_decoder": "/path/to/decoder.int8.onnx",
"stt_tokens": "/path/to/tokens.txt",
"stt_language": "en",
"kws_encoder": "/path/to/kws-encoder.onnx",
"kws_decoder": "/path/to/kws-decoder.onnx",
"kws_joiner": "/path/to/kws-joiner.onnx",
"kws_tokens": "/path/to/kws-tokens.txt",
"kws_keywords": "/path/to/c2_keywords.txt",
"kws_gain": 1.0,
"input_device": ""
}
}
| Field |
Description |
tts_backend |
"kokoro" (neural) or "say" (macOS built-in) |
tts_voice |
Language tag for Kokoro (en-us) or voice name for say (Samantha) |
tts_speaker_id |
Speaker index for Kokoro (default 0) |
tts_speed |
Words/min for say (default 200) or speed multiplier for Kokoro (default 1.0) |
vad_model |
Path to Silero VAD .onnx model |
stt_encoder/decoder/tokens |
sherpa-onnx transducer STT model files |
stt_language |
STT language code (default "en") |
kws_* |
sherpa-onnx keyword spotter model files |
kws_keywords |
File listing wake words, one per line prefixed with @label |
kws_gain |
Amplitude boost applied to KWS input only (0 = disabled) |
input_device |
Microphone device name (empty = system default) |
Voice is enabled automatically when vad_model, stt_encoder, and stt_decoder are set. KWS (wake word) is optional; without it voice is activated manually with Tab.
Startup
c2 [flags]
Core flags
| Flag |
Short |
Description |
--topic <name> |
-t |
Open specific topic |
--profile <name> |
-p |
Use specific profile |
--model <name> |
-m |
Override model |
--text-mode |
|
Disable voice; keyboard only |
--theme <auto|light|dark> |
|
Color theme (default: auto) |
--fold-lines <N> |
|
Fold entries longer than N lines (default: 20, 0=never) |
--fold-on-start |
|
Start with all long entries folded |
--chat-labels |
|
Prefix turns with [you]/[profile] (default: true) |
--no-tui / -nw |
|
Headless/CLI mode |
--tts |
|
Speak response in CLI mode |
--version |
-v |
Print version and exit |
Admin flags (headless)
| Flag |
Description |
--topic-list |
List all topics |
--topic-new <name> |
Create topic |
--topic-delete |
Delete current topic |
--topic-clear |
Erase topic history |
--topic-default-set <name> |
Set default topic |
--profile-list |
List profiles |
--profile-default-set <name> |
Set default profile |
--resource-list |
List topic resources |
--resource-remove <name> |
Delete resource |
--topic-resource <path> |
Copy file to topic resources |
--system-set <text> |
Set system prompt |
--system-file <path> |
Set system prompt from file |
--stats |
Show usage and cost |
--status |
Show effective defaults |
--config |
Print resolved config |
--delete-last [N] |
Delete last N exchanges |
TUI Layout
┌──────────────────────────────────────────────────────────────┐
│ c2 topic: default profile: gpt4 ● VOICE MODE │
├──────────────────────────────────────────────────────────────┤
│ │
│ CONVERSATION PANE (scrollable) │
│ [you] hello │
│ [gpt4] Hello! How can I help? │
│ │
├──────────────────────────────────────────────────────────────┤
│ > type a message or speak after wake word │
├──────────────────────────────────────────────────────────────┤
│ 42 in · 18 out · 340ms · $0.001 topic: 3 · $0.01 │
└──────────────────────────────────────────────────────────────┘
The status bar is context-sensitive:
- Idle: token counts, latency, cost
- Slash command active: command completions list
- Command output: scrollable results pane
- Streaming:
❄ streaming ●●●
- Transcribing:
❄ transcribing ●●●
- TTS playing:
♪ #3 1.2x [ slower ] faster
Key Bindings
Global
| Key |
Action |
Enter |
Send prompt |
Ctrl+J |
Insert newline (multi-line input) |
Tab |
Fill completion (input) / toggle voice/text mode |
Esc |
Close pane / clear input / return to input |
Ctrl+C |
Cancel streaming / quit |
Ctrl+L |
Clear screen |
Ctrl+T |
Switch topic (completion list) |
Ctrl+P |
Switch profile (completion list) |
Ctrl+N |
Toggle focus: input ↔ conversation |
Ctrl+S |
Copy current entry to clipboard |
Conversation pane (when focused)
| Key |
Action |
↑ / ↓ |
Navigate exchanges |
PgUp / PgDn |
Scroll content |
f |
Fold/unfold current entry |
s |
Speak current entry (TTS) |
TTS playback
| Key |
Action |
[ |
Decrease speed |
] |
Increase speed |
Space / s |
Stop playback |
Resource viewer overlay
| Key |
Action |
↑ / ↓ |
Move cursor line by line |
PgUp / PgDn |
Move cursor by half page |
g |
Jump to top |
G |
Jump to bottom |
s |
Start TTS from cursor position (or stop if playing) |
e |
Open in $EDITOR |
[ / ] |
Decrease / increase TTS speed |
Ctrl+X / q |
Close overlay |
Slash Commands
Type / in the input pane to bring up completions.
Topic
| Command |
Description |
/topic [name] |
Show current topic info |
/topic-switch <name> |
Switch to topic |
/topic-new <name> |
Create and switch to topic |
/topic-list |
List all topics |
/topic-delete [name] |
Delete topic |
/topic-clear |
Erase topic history |
/topic-default |
Show default topic |
/topic-default-set <name> |
Set default topic |
/topic-summary |
Show context summary |
/topic-history [n] |
Show last N exchanges |
Resource
| Command |
Description |
/resource-add <file> |
Copy file to topic resources |
/resource-list [topic] |
List topic resources |
/resource-view <name> |
Open resource in full-screen overlay |
/resource-edit <name> |
Edit resource in $EDITOR |
/resource-remove <name> |
Delete resource |
/resource-delete <name> |
Delete resource (alias) |
Resource files are referenced in prompts with @name. Supported path forms:
@resource-name topic resources folder
@subdir/name nested resource
@./relative/path relative to cwd
@/absolute/path absolute path
@~/path home-relative path
Profile
| Command |
Description |
/profile [name] |
Show profile info |
/profile-switch <name> |
Switch profile |
/profile-list |
List all profiles |
/profile-default |
Show default profile |
/profile-default-set <name> |
Set default profile |
System prompt
| Command |
Description |
/system |
Show system prompt |
/system-set <text> |
Set system prompt |
/system-clear |
Remove system prompt |
Info
| Command |
Description |
/config |
Show resolved config |
/status |
Show effective defaults |
/stats |
Usage and cost stats |
/voice-commands |
List all voice phrases |
/help [group] |
Show help (groups: topic resource profile system session info notes files nav theme view) |
/delete-last [n] |
Delete last N exchanges |
View
| Command |
Description |
/tts [on|off] |
Toggle auto-speech (no arg = toggle) |
/play-all |
Speak all entries in conversation |
/fold |
Collapse long entries |
/unfold |
Expand long entries |
/theme [light|dark|auto] |
Switch or show theme |
Voice Mode
Wake word
Say "Computer" to wake c2. The pipeline is:
Microphone
└─► KWS (always on) ─► "computer" detected
└─► AWAKE state: energy buffer + STT
├─► command match ─► execute locally
└─► no match ─► send to LLM
Voice FSM states
| State |
Description |
IDLE |
KWS only; waiting for wake word |
AWAKE |
Wake word heard; listening for command (750ms silence or 4s cap) |
DICTATING |
Recording prompt via VAD+STT |
CONVERSING |
Continuous conversation; VAD+STT per turn |
EXECUTING |
LLM call or TTS in progress |
PAUSED |
Text mode active; pipeline idle |
Voice commands
Speak naturally after the wake word. Filler words ("please", "um", "hey", "just") are stripped automatically.
Session
| Say |
Action |
| "clear" |
Clear input |
| "stop" / "cancel" |
Stop TTS or cancel |
| "resume" / "keep going" |
Resume TTS |
| "start session" |
Enter conversation mode |
| "stop session" |
Leave conversation mode |
| "continue" / "never mind" / "thank you" |
Resume from EXECUTING |
Conversation
| Say |
Action |
| "ask" / "question" / "query" |
Send input to LLM |
| "note" / "take note" |
Save note to history |
| "replay" / "repeat" |
Re-speak last response |
| "play last" / "play it" |
Speak last message |
| "play all" / "read all" |
Speak all entries |
| "scratch that" / "clear that" |
Clear input buffer |
| "delete last" / "undo" |
Delete last exchange |
| "fold" / "collapse" |
Fold long entries |
| "unfold" / "expand" |
Expand entries |
| "toggle tts" / "tts on" / "tts off" |
Toggle auto-speech |
Topic (accelerators — pre-fill + completion picker)
| Say |
Action |
| "topic info" |
Show topic info |
| "list topics" / "topics" |
List all topics |
| "switch topic" / "change topic" |
Pre-fill /topic-switch + picker |
| "new topic" |
Pre-fill /topic-new |
| "clear topic" / "clear history" |
Clear topic history |
| "delete topic" |
Pre-fill /topic-delete + picker |
| "topic default" |
Show default topic |
| "set default topic" |
Pre-fill /topic-default-set + picker |
| "topic summary" |
Show summary |
| "topic history" |
Show history |
Profile (accelerators)
| Say |
Action |
| "profile info" |
Show profile info |
| "list profiles" / "profiles" |
List all profiles |
| "switch profile" / "change model" |
Pre-fill /profile-switch + picker |
| "profile default" |
Show default profile |
| "set default profile" |
Pre-fill /profile-default-set + picker |
Resource (accelerators)
| Say |
Action |
| "list resources" / "resources" |
List topic resources |
| "remove resource" / "delete resource" |
Pre-fill /resource-remove + picker |
| "view resource" / "open resource" |
Pre-fill /resource-view + picker |
| "edit resource" |
Pre-fill /resource-edit + picker |
System
| Say |
Action |
| "system prompt" / "show system" |
Show system prompt |
| "clear system" |
Remove system prompt |
Info
| Say |
Action |
| "config" / "show config" |
Show resolved config |
| "status" / "show status" |
Show effective defaults |
| "stats" / "statistics" |
Usage and cost |
| "voice commands" / "what can I say" |
List voice phrases |
| "help" / "show help" |
Show help |
Voice accelerators
For commands that require a parameter (topic name, profile name, resource name), saying the command pre-fills the input and opens a completion picker. Use ↑/↓ to select, Enter to confirm — no need to spell out the name.
Architecture
c2/
├── main.go entry point, flag parsing
├── headless.go CLI mode operations
├── audio/ PortAudio capture + playback
├── speech/ VAD (Silero), STT (sherpa-onnx), TTS (Kokoro), KWS
├── c2config/ voice/audio config
├── tui/ Bubbletea TUI
│ ├── tui.go startup + voice pipeline goroutine
│ ├── model.go state
│ ├── update.go event handling + voice FSM
│ ├── view.go rendering
│ ├── commands.go slash command handlers
│ ├── keys.go key bindings
│ └── voicefsm.go FSM state types + command synonyms
├── config/ provider config
├── engine/ LLM engine
├── provider/ API providers
├── store/ topic persistence
└── strategy/ context strategy
Key dependencies:
All topics, history, profiles, and config live in ~/.c2/.
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