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sonichi/sutando/skills/gemini-tts/SKILL.md

gemini-tts

Render text to mp3 via Google Gemini Flash TTS. Free-tier eligible (1500 req/day). Use for video narration, demo voiceovers, audio notes. Parallels openai-tts; default for make-viral-video.

Source repository stars
359
Declared platforms
0
Static risk flags
1
Last source update
2026-07-28
Source checked
2026-07-28
DecisionCompatibilityInstallWorkflowPermissionsEvidenceSource

Decision brief

What it does—and where it fits

Synthesize speech via Google's gemini-2.5-flash-preview-tts (or -pro-tts / -lite-preview-tts per env override). Reads GEMINIAPIKEY from .env.

Best for

    Not for

    • Tasks that require unconfirmed production actions or broad system permissions.
    • Environments where the pinned source and install steps cannot be inspected.

    Compatibility matrix

    Platform support, with evidence labels

    PlatformStatusEvidenceWhat to check
    CodexNot declaredNo explicit evidencePortability before use
    Claude CodeNot declaredNo explicit evidencePortability before use
    CursorNot declaredNo explicit evidencePortability before use
    Gemini CLINot declaredNo explicit evidencePortability before use
    Open the compatibility checker

    Installation

    Inspect first. Install second.

    The source command is displayed only when detected. A safe inspection prompt is always available so your agent can explain every action before execution.

    Source-detected install commandSource
    npx skills add https://github.com/sonichi/sutando --skill "skills/gemini-tts"
    Safe inspection promptEditorial

    Inspect the Agent Skill "gemini-tts" from https://github.com/sonichi/sutando/blob/6a8f0fccd32e5aa620a3572c8885544f144bb6fe/skills/gemini-tts/SKILL.md at commit 6a8f0fccd32e5aa620a3572c8885544f144bb6fe. List every install step, command, network request, credential, file read/write, external action, and rollback step. Explain whether it fits my task. Do not install or execute anything until I approve.

    Workflow

    What the source asks the agent to do

    1. 01

      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.

      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.
    2. 02

      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 li…

      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 →…
    3. 03

      Model selection

      Default: gemini-2.5-flash-preview-tts (free tier, 1500 req/day, $0 within quota).

      gemini-2.5-pro-tts — paid, higher fidelitygemini-2.5-flash-lite-preview-tts — preview, fastergemini-3.1-flash-tts-preview — preview
    4. 04

      Examples

      Default output path: results/gemini-tts-{epoch}.mp3.

      Default output path: results/gemini-tts-{epoch}.mp3.

    Permission review

    Static risk signals and limitations

    Runs scripts

    medium · line 20

    The documentation asks the agent to run terminal commands or scripts.

    bash "$SKILL_DIR/scripts/synthesize.sh" -- "[whispers] Pull request 691 has landed."

    Runs scripts

    medium · line 35

    The documentation asks the agent to run terminal commands or scripts.

    bash "$SKILL_DIR/scripts/synthesize.sh" -- "Hello, this is Sutando."

    Evidence record

    Why each signal appears

    EvidenceSourceComputedTestedEditorial
    SignalValueEvidence typeMeaning
    Quality score70/100ComputedDocumentation, specificity, maintenance, and trust rules
    Repository stars359SourceRepository attention, not individual Skill quality
    Compatibility0 platformsSourceDeclared in the catalog source record
    Usage guideautomated source guideEditorialGenerated or reviewed according to the visible evidence level

    Pinned source

    Provenance and original SKILL.md

    Repository
    sonichi/sutando
    Skill path
    skills/gemini-tts/SKILL.md
    Commit
    6a8f0fccd32e5aa620a3572c8885544f144bb6fe
    License
    MIT
    Collected
    2026-07-28
    Default branch
    main
    View the original SKILL.md

    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 fidelity
    • gemini-2.5-flash-lite-preview-tts — preview, faster
    • gemini-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.

    When to fall back to openai-tts

    The make-viral-video skill auto-falls-back to OpenAI TTS when:

    • Gemini API returns 4xx/5xx
    • Gemini quota hit (429)
    • GEMINI_API_KEY missing
    • TTS_PROVIDER=OPENAI env override set

    If Invoked As A Slash Command

    If ARGUMENTS is empty, ask the user for the text. Otherwise:

    bash "$SKILL_DIR/scripts/synthesize.sh" -- "$ARGUMENTS"