diff --git a/packages/opencode/src/kilocode/provider/provider.ts b/packages/opencode/src/kilocode/provider/provider.ts
index 13ec8bdddd..21345881ee 100644
--- a/packages/opencode/src/kilocode/provider/provider.ts
+++ b/packages/opencode/src/kilocode/provider/provider.ts
@@ -103,8 +103,10 @@ type Variants = NonNullable<Provider.Model["variants"]>
 type Generate = (model: Provider.Model) => Variants
 
 export function customProviderVariants(model: Provider.Model, npm: unknown, generate: Generate): Variants {
+  if (model.variants && Object.keys(model.variants).length > 0) return model.variants
+
   const supported = typeof npm === "string" && CUSTOM_PROVIDER_PACKAGES.has(npm) && model.api.npm === npm
-  const variants = generate(supported ? { ...model, variants: {} } : model)
+  const variants = generate(model)
   if (Object.keys(variants).length > 0) return variants
   if (!model.capabilities.reasoning || !supported) return variants
 
diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index e8f134f287..c830ad8bb7 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -1528,11 +1528,9 @@ const layer = Layer.effect(
               ...patchKiloConfigModel(model, existingModel), // kilocode_change
             }
             // kilocode_change start
-            const generated = customProviderVariants(
-              parsedModel,
-              model.provider?.npm ?? provider.npm,
-              ProviderTransform.variants,
-            )
+            const generated = Object.keys(model.variants ?? {}).length
+              ? {}
+              : customProviderVariants(parsedModel, model.provider?.npm ?? provider.npm, ProviderTransform.variants)
             const merged = mergeDeep(generated, model.variants ?? {})
             // kilocode_change end
             parsedModel.variants = mapValues(
diff --git a/packages/opencode/test/kilocode/custom-provider-variants.test.ts b/packages/opencode/test/kilocode/custom-provider-variants.test.ts
index e3a6e6be17..7de3036fd7 100644
--- a/packages/opencode/test/kilocode/custom-provider-variants.test.ts
+++ b/packages/opencode/test/kilocode/custom-provider-variants.test.ts
@@ -10,14 +10,13 @@ import { testEffect } from "../lib/effect"
 const it = testEffect(LayerNode.compile(LayerNode.group([Provider.node, Env.node, Plugin.node])))
 
 it.instance(
-  "adds fallback efforts to configured reasoning models and merges explicit variants",
+  "uses configured variants instead of inferred reasoning efforts",
   () =>
     Effect.gen(function* () {
       const providers = yield* Provider.use.list()
       const model = providers[ProviderV2.ID.make("custom")]?.models["qwen-custom"]
 
-      expect(Object.keys(model?.variants ?? {})).toEqual(["none", "low", "medium", "xhigh", "max", "custom"])
-      expect(model?.variants?.none).toEqual({ reasoningEffort: "none" })
+      expect(Object.keys(model?.variants ?? {})).toEqual(["custom"])
       expect(model?.variants?.high).toBeUndefined()
       expect(model?.variants?.custom).toEqual({ reasoningEffort: "custom" })
     }),
diff --git a/packages/opencode/test/kilocode/provider-reasoning-options.test.ts b/packages/opencode/test/kilocode/provider-reasoning-options.test.ts
index 268d27f439..5987819421 100644
--- a/packages/opencode/test/kilocode/provider-reasoning-options.test.ts
+++ b/packages/opencode/test/kilocode/provider-reasoning-options.test.ts
@@ -168,6 +168,18 @@ describe("custom provider fallback reasoning efforts", () => {
     expect(customProviderVariants(model, model.api.npm, () => generated)).toBe(generated)
   })
 
+  test("prefers configured variants to inference", () => {
+    const variants = { custom: { reasoningEffort: "custom" } }
+    for (const npm of ["@ai-sdk/openai-compatible", "@ai-sdk/openai", "@ai-sdk/anthropic"]) {
+      const model = mockModel({ api: { id: "custom", url: "https://api.test.com", npm }, variants })
+      expect(
+        customProviderVariants(model, npm, () => {
+          throw new Error("inference should not run")
+        }),
+      ).toBe(variants)
+    }
+  })
+
   test("requires a reasoning model with an explicitly configured supported package", () => {
     const npm = "@ai-sdk/openai-compatible"
     const plain = mockModel({