fix(provider): preserve OpenRouter small model effort (#35478)

Co-authored-by: Aiden Cline <63023139+rekram1-node@users.noreply.github.com>

packages/opencode/src/provider/transform.ts

@@ -1240,9 +1240,6 @@ export function smallOptions(model: Provider.Model) {
     return mergeDeep(base, small)
   }
   if (model.providerID === "openrouter" || model.providerID === "llmgateway") {
-    if (model.providerID === "openrouter" && small.reasoning?.effort === "low") {
-      return { reasoning: { effort: "none" } }
-    }
     if (Object.keys(small).length === 0 && model.api.id.includes("google")) {
       return { reasoning: { enabled: false } }
     }

packages/opencode/test/provider/transform.test.ts

@@ -4638,12 +4638,12 @@ describe("ProviderTransform.smallOptions - gpt-5 chat/search", () => {
   }
 })
 
-test("ProviderTransform.smallOptions disables OpenRouter reasoning when the weakest effort is low", () => {
+test("ProviderTransform.smallOptions preserves the weakest OpenRouter reasoning effort", () => {
   expect(
     ProviderTransform.smallOptions({
       providerID: "openrouter",
       api: {
-        id: "anthropic/claude-sonnet-4.6",
+        id: "google/gemini-3.5-flash",
         npm: "@openrouter/ai-sdk-provider",
       },
       variants: {
@@ -4652,7 +4652,7 @@ test("ProviderTransform.smallOptions disables OpenRouter reasoning when the weak
         high: { reasoning: { effort: "high" } },
       },
     } as any),
-  ).toEqual({ reasoning: { effort: "none" } })
+  ).toEqual({ reasoning: { effort: "low" } })
 })
 
 describe("ProviderTransform.smallOptions - google thinking controls", () => {