sag

sag 🗣️ — “Mac-style speech with ElevenLabs or 60db”

One-liner TTS that works like say: stream to speakers by default, list voices, or save audio files.

Install

Homebrew (macOS):

brew install steipete/tap/sag  # auto-taps steipete/tap

Prebuilt binaries:

• Download Linux, macOS, and Windows archives from the latest GitHub release.
• macOS downloads require macOS 15 or later and are Developer ID signed and notarized by Peter Steinberger, so direct downloads pass Gatekeeper.
• On Linux, unpack the linux_amd64 archive and place sag somewhere on your PATH, for example /usr/local/bin.

Go toolchain:

go install github.com/steipete/sag/cmd/sag@latest

Requires Go 1.25+.

Debian/Ubuntu source build prerequisites:

sudo apt install build-essential pkg-config libasound2-dev

Configuration

sag supports two TTS providers and auto-selects one from your configured credentials:

• ElevenLabs — ELEVENLABS_API_KEY (or --api-key, or --api-key-file / ELEVENLABS_API_KEY_FILE / SAG_API_KEY_FILE)
• 60db (api.60db.ai) — SIXTYDB_API_KEY (or SIXTYDB_API_KEY_FILE)

Selection rules:

• Only one key set → that provider is used.
• Both keys set → error; unset one provider key and retry.
• Neither set → error.

Optional ElevenLabs defaults: ELEVENLABS_VOICE_ID or SAG_VOICE_ID. Override the active provider host with --base-url.

60db support is intentionally narrow and follows the live API behavior:

• voice discovery merges GET /default-voices and GET /myvoices
• synthesis uses POST /tts-synthesize, validates every NDJSON frame, and wraps the returned 48 kHz PCM as WAV
• incomplete or malformed provider responses fail instead of producing a truncated file
• 60db currently supports WAV playback/output only; its live synthesis response is buffered rather than streamed

Shared speak flags that work on both providers include --voice, --speed / --rate, --stability, --similarity, --play, --output, --timeout, and --metrics. On 60db, --format accepts only wav, and an explicit --stream is rejected.

ElevenLabs-only speak flags fail fast on 60db: --model-id, --style, --speaker-boost / --no-speaker-boost, --seed, --normalize, --lang, and --latency-tier. --stability / --similarity still use the CLI's 0..1 range and are scaled to 60db's documented 0..100 API values. See docs/providers.md for provider-specific details.

Usage

Features:

• macOS say-style default: sag "Hello" routes to speak automatically.
• Streaming playback to speakers with optional file output.
• Voice discovery via sag voices and -v ?.
• Speed/rate controls, latency tiers, and format inference from output extension.
• Model selection via --model-id (defaults to eleven_v3; use eleven_multilingual_v2 for a stable baseline).

Speak with ElevenLabs streaming:

sag speak -v Roger "Hello world"

Call it like macOS say: omitting the subcommand pipes text to speak by default.

sag "Hello world"

macOS say compatibility shortcuts (subcommand optional):

sag -v Roger -r 200 "Faster speech"
sag -o out.mp3 "Save to file"
sag -v ?      # list voices

More examples:

echo "piped input" | sag speak -v Roger
sag speak -v Roger --stream --latency-tier 3 "Faster start"
sag speak -v Roger --speed 1.2 "Talk a bit faster"
sag speak -v Roger --model-id eleven_multilingual_v2 "Use stable v2 baseline"
sag speak -v Roger --output out.wav --format pcm_44100 "Wave output"
SIXTYDB_API_KEY=... sag speak -v Aria --output out.wav --no-play "60db WAV output"

Key flags (subset):

• -v, --voice voice name or ID (? to list)
• --api-key-file read API key from a file
• -r, --rate words per minute (maps to ElevenLabs speed; default 175)
• -f, --input-file read text from file (- for stdin)
• -o, --output write audio file; format inferred by extension (.wav -> PCM, .mp3 -> MP3)
• --speed explicit speed multiplier (0.5–2.0)
• --stability v3: 0|0.5|1 (Creative/Natural/Robust); v2/v2.5: 0..1 (higher = more consistent, less expressive)
• --similarity / --similarity-boost 0..1 (higher = closer to the reference voice)
• --style 0..1 (higher = more stylized delivery; model/voice dependent)
• --speaker-boost / --no-speaker-boost toggle clarity boost (model dependent)
• --seed 0..4294967295 best-effort repeatability across runs
• --normalize auto|on|off numbers/units/URLs normalization (when set)
• --lang en|de|fr|... 2-letter ISO 639-1 language code (when set)
• --stream/--no-stream stream while generating (default on)
• --latency-tier 0–4 lower latency tiers
• --play/--no-play control speaker playback
• --player auto|afplay|oto choose playback backend (auto uses afplay on macOS and oto elsewhere; also configurable via SAG_PLAYER)
• --timeout maximum TTS generation time, e.g. --timeout 5m; 0 means no internal timeout (default, also configurable via SAG_TIMEOUT)
• --metrics print basic stats to stderr

Voices:

sag voices --search english --limit 20
sag voices --search english --limit 5 --try
sag voices --query "crazy scientist" --limit 5 --try
sag voices --label accent=british --label use_case=character --limit 10

Prompting (make it sound better)

Run:

sag prompting

Highlights:

• v2/v2.5: SSML pauses via <break time="1.5s" /> (v3 does not support SSML breaks).
• v3: use audio tags like [whispers] and pause tags like [short pause].
• Use the voice knobs: --stability, --similarity, --style, --speaker-boost, plus request controls --seed, --normalize, --lang.

Models / engines

sag supports any ElevenLabs model_id via --model-id (we pass it through). Practical defaults + common IDs:

Engine	--model-id	Prompting style	Best for
v3 (alpha)	eleven_v3 (default)	Audio tags like [whispers], [short pause] (no SSML <break>)	Most expressive / “acting”
v2 (stable)	eleven_multilingual_v2	SSML <break> supported	Reliable baseline, simple prompts
v2.5 Flash	eleven_flash_v2_5	SSML <break> supported	Ultra-low latency (~75ms) + 50% lower price per character
v2.5 Turbo	eleven_turbo_v2_5	SSML <break> supported	Low latency (~250–300ms) + 50% lower price per character

Notes:

• SSML <break> works on v2/v2.5, not v3. Use pause tags on v3 instead.
• Input limits differ by engine (v3: 5,000 chars; v2: 10,000 chars; v2.5 Turbo/Flash: 40,000 chars). If you hit limits, chunk text and stitch audio.
• --normalize on may not be available for v2.5 Turbo/Flash (higher latency); prefer auto/off if it errors.
• Source of truth: ElevenLabs “Models” docs.

Timeout considerations

Longer text can take more than a minute to generate, especially with eleven_v3. By default, sag does not add its own generation timeout, so callers such as agents, scripts, shells, or CI jobs can choose the right outer timeout without getting a valid-but-truncated audio file from an internal SIGTERM.

If you want sag itself to stop a request, set an explicit duration:

sag --timeout 5m --no-play -o long.mp3 "Long text..."
SAG_TIMEOUT=5m sag --no-play -o long.mp3 "Long text..."

For long agent/script runs, give the outer process timeout enough headroom and verify generated audio duration when truncation would matter:

ffprobe -v quiet -show_entries format=duration -of csv=p=0 long.mp3

Development

• With pnpm:
  • pnpm format
  • pnpm lint
  • pnpm test
  • pnpm build
  • pnpm sag -- --help (passes args to the Go binary)
• Direct Go:
  • Format: go fmt ./...
  • Lint: golangci-lint run
  • Tests: go test ./...
  • Build: go build ./cmd/sag

Limitations

• One provider API key is required.
• Voice defaults to first available if not provided.
• Non-mac platforms: playback still works via MP3/WAV decoding + oto, but device selection flags are no-ops.