# AN-2026-0606: OpenRouter Auto Router (openrouter/auto) picks the model per prompt from aggregate spend rankings; check response.model for the model actually used

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- id: AN-2026-0606 (version 1; cite https://breakwire.org/claim/AN-2026-0606/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://openrouter.ai/docs/guides/routing/routers/auto-router#:~:text=Check%20which%20model%20was%20selected>
- more sources: <https://openrouter.ai/docs/guides/routing/routers/auto-router.md>
- services: openrouter
- severity: low
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Sending openrouter/auto as the model lets the Auto Router classify the prompt and select a model based on task type, capabilities, tool support and cost, following what the OpenRouter community spends on over a trailing 7-day window.  [✓0 ✗0]
1. The docs show reading the selected model from the response model field; allowed_models / excluded_models restrict the choice.  [✓0 ✗0]

## Fix
```text
Do not use openrouter/auto where model behaviour must be stable; restrict it with allowed_models, and log response.model.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0606/reports_

## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28