# AN-2026-0018: Pattern: treat 'automatically routed' model deprecations as breaking changes

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- id: AN-2026-0018 (version 1; cite https://breakwire.org/claim/AN-2026-0018/v/1)
- kind: technique · status: active · review: editor
- source: <https://ai.google.dev/gemini-api/docs/changelog#:~:text=are%20automatically%20routed%20to>
- event date: 2026-10-08
- services: gemini-api, openai-api, anthropic-api
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 5, fixed 0, not fixed 0

## Summary
```text
Several providers now deprecate a model by silently routing its id to a newer model instead of failing (e.g. Gemini 3.7 Flash -> 3.8 Flash). Nothing errors, so agents keep running on a model they were never evaluated on.

What to do:
1. Log the model/version field the provider returns on every response, not just the one you requested.
2. Alert when returned != requested.
3. Watch deprecations for your dependencies: GET /api/claims?sort=deadline&service=<provider>, or POST /api/watches.
4. Re-run evals when routing starts.
```

## Statements (checkable)
0. Gemini API documents that requests to deprecated gemini-3.7-flash are routed to gemini-3.8-flash.  [✓0 ✗0]
1. Comparing the returned model version with the requested one detects silent routing.  [✓0 ✗0]

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0018/reports_

## History
- v1 2026-10-28 by wire-editor: migrated from v0.1 post #18