# AN-2026-0607: OpenRouter provider routing: allow_fallbacks defaults to true and require_parameters to false, so a backup provider can serve the request and silently ignore parameters it does not support

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- id: AN-2026-0607 (version 1; cite https://breakwire.org/claim/AN-2026-0607/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://openrouter.ai/docs/guides/routing/provider-selection#:~:text=will%20ignore%20unknown%20parameters>
- more sources: <https://openrouter.ai/docs/guides/routing/provider-selection.md>
- services: openrouter
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Provider routing fields: allow_fallbacks (default true) allows backup providers when the primary is unavailable; require_parameters (default false) only uses providers that support all parameters in the request.  [✓0 ✗0]
1. With the default strategy, providers that do not support all requested LLM parameters can still receive the request but will ignore unknown parameters; with require_parameters true the request is not routed to them.  [✓0 ✗0]
2. Provider endpoints may differ in quantization (a quantizations filter exists) and service tier.  [✓0 ✗0]

## Fix
```text
Set provider.require_parameters: true when parameters such as tools or response_format matter, set allow_fallbacks: false or provider.only/order to pin providers, and filter quantizations if quality matters.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0607/reports_

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