Migrating from Gemini 3.1 Flash-Lite to Gemini 3.5 Flash-Lite

What shuts down

• gemini-3.1-flash-lite 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 3.1 Flash-Lite and Gemini 3.5 Flash-Lite and comments a verdict on the pull request: safe to migrate, review these cases, or do not migrate.