Migrating from Gemini TTS previews to Gemini 3.8 Flash TTS or Flash-Lite TTS

What shuts down

• gemini-3.1-flash-tts-preview and its dated snapshots
• gemini-2.5-flash-preview-tts and its dated snapshots
• gemini-2.5-pro-preview-tts and its dated snapshots

Source: ai.google.dev. Check your provider’s deprecations page before you plan around a date.

Find every place you use it

The free scanner flags every reference in your repository and opens one issue with the deadline:

npx swapvera-scan .

Or on every push, as a GitHub Action:

- uses: pixelric-spec/swapvera-scanner@v1
  with:
    fail-on: retired

What can change when you swap the ID

Prompts tuned for one model rarely transfer perfectly to the next. Check these before you merge:

• Structured output: JSON that stays valid and keeps the same field types.
• Tool calls: the same tools called with the same arguments, and no calls where there were none.
• Instructions in your system prompt that the new model follows differently, such as length limits or policies it must quote.
• Refusals and safety behavior on your edge cases.
• Parameters the new model rejects, such as a fixed temperature on reasoning models.
• Latency and cost per call at your real input sizes.

What broke for other teams

Check the switch on your own prompts

Swapvera runs your cases on Gemini TTS previews and Gemini 3.8 Flash TTS or Flash-Lite TTS and comments a verdict on the pull request: safe to migrate, review these cases, or do not migrate.