Fix OpenRouter routing compat for custom providers

closes #5347

packages/ai/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed OpenRouter routing preferences on OpenAI-compatible custom providers to send `compat.openRouterRouting` even when `baseUrl` does not point directly at OpenRouter ([#5347](https://github.com/earendil-works/pi/issues/5347)).
+
 ## [0.78.1] - 2026-06-04
 
 ### Added

packages/ai/src/providers/openai-completions.ts

@@ -610,7 +610,7 @@ function buildParams(
 	}
 
 	// OpenRouter provider routing preferences
-	if (model.baseUrl.includes("openrouter.ai") && model.compat?.openRouterRouting) {
+	if (model.compat?.openRouterRouting) {
 		(params as any).provider = model.compat.openRouterRouting;
 	}
 

packages/ai/src/types.ts

@@ -403,7 +403,7 @@ export interface OpenAICompletionsCompat {
 		| "qwen-chat-template"
 		| "string-thinking"
 		| "ant-ling";
-	/** OpenRouter-specific routing preferences. Only used when baseUrl points to OpenRouter. */
+	/** OpenRouter-compatible routing preferences sent as the `provider` request field. */
 	openRouterRouting?: OpenRouterRouting;
 	/** Vercel AI Gateway routing preferences. Only used when baseUrl points to Vercel AI Gateway. */
 	vercelGatewayRouting?: VercelGatewayRouting;