Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add sonichi/sutando --skill gemini-ttsgit clone --depth 1 https://github.com/sonichi/sutandoWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/sonichi/sutando/gemini-tts)<a href="https://agentmods.dev/skills/sonichi/sutando/gemini-tts"><img src="https://agentmods.dev/badge/skills/sonichi/sutando/gemini-tts.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00053 | $0.00795 |
| Opus 5 | $0.00026 | $0.00398 |
| Sonnet 5 | $0.00011 | $0.00159 |
| Haiku 4.5 | $0.00005 | $0.00080 |
Grade A, and why
gemini-tts scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Gemini TTS
Synthesize speech via Google's gemini-2.5-flash-preview-tts (or -pro-tts / -lite-preview-tts per env override). Reads GEMINI_API_KEY from .env.
This is offline synthesis — distinct from voice-agent's bidirectional Gemini Live audio. Same model family, different surface (POST text → get audio bytes back, no streaming).
Usage: /gemini-tts [text]
ARGUMENTS: $ARGUMENTS
Voices
Aoede (default — alto, neutral), Charon (baritone, news-anchor), Kore (mid, expressive), Puck (high, conversational). Per Lucy's 2026-05-09 testing: Aoede is the closest match to OpenAI's sage.
Audio tags for expression
Inline bracket tags like [whispers], [excitedly], [slowly] are interpreted as stylistic direction, not spoken literally. Empirically verified against gemini-2.5-flash-preview-tts (per PR #646 comment): [whispers] hello → 1.05s audio; hello alone → 1.01s. If the tag were spoken literally as 8 words, the clip would be ~5× longer.
bash "$SKILL_DIR/scripts/synthesize.sh" -- "[whispers] Pull request 691 has landed."
Model selection
Default: gemini-2.5-flash-preview-tts (free tier, 1500 req/day, $0 within quota).
Override via GEMINI_TTS_MODEL env var:
gemini-2.5-pro-tts— paid, higher fidelitygemini-2.5-flash-lite-preview-tts— preview, fastergemini-3.1-flash-tts-preview— preview
Examples
bash "$SKILL_DIR/scripts/synthesize.sh" -- "Hello, this is Sutando."
bash "$SKILL_DIR/scripts/synthesize.sh" --voice Charon --out /tmp/intro.mp3 -- "Hi."
GEMINI_TTS_MODEL=gemini-2.5-pro-tts bash "$SKILL_DIR/scripts/synthesize.sh" -- "High-fidelity narration."
Default output path: results/gemini-tts-{epoch}.mp3.
Cost
Free tier: $0 within 1500 req/day quota. For our cadence (a few demos a day), stays free indefinitely. Paid (Flash): $0.50 / 1M input tokens + $10.00 / 1M output tokens.
Compared to OpenAI TTS (gpt-4o-mini-tts) at ~$0.02 per 60s: Gemini Flash is free-equivalent for typical demo workloads.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 7d ago First seen · 70 lines · 53 tokens per session scan A 5d19749a95e0
gemini-tts is a skill published in the GitHub repository sonichi/sutando (392 stars, last pushed today), licensed MIT. It adds 53 tokens to every session and 795 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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