diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 72ec881e7b..1021d83f02 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -617,14 +617,6 @@ function googleThinkingBudgetMax(apiId: string) {
   return 24_576
 }
 
-function googleSmallThinkingConfig(apiId: string) {
-  const levels = googleThinkingLevelEfforts(apiId)
-  if (apiId.toLowerCase().includes("gemini-3")) {
-    return { thinkingLevel: levels.includes("minimal") ? "minimal" : levels.includes("low") ? "low" : "high" }
-  }
-  return { thinkingBudget: googleThinkingBudgetMax(apiId) === 32_768 ? 128 : 0 }
-}
-
 export function variants(model: Provider.Model): Record<string, Record<string, any>> {
   if (!model.capabilities.reasoning) return {}
 
@@ -1184,40 +1176,27 @@ export function options(input: {
 }
 
 export function smallOptions(model: Provider.Model) {
+  const small = Object.values(model.variants ?? {})[0] ?? {}
   if (
     model.providerID === "openai" ||
     model.api.npm === "@ai-sdk/openai" ||
     model.api.npm === "@ai-sdk/github-copilot"
   ) {
-    if (model.api.id.includes("gpt-5")) {
-      if (model.api.id.includes("-chat")) {
-        if (gpt5Version(model.api.id) === undefined) return { store: false }
-        return { store: false, reasoningEffort: "medium" }
-      }
-      if (model.api.id.includes("search-api")) return { store: false }
-      if (model.api.id.includes("5.") || model.api.id.includes("5-mini")) {
-        return { store: false, reasoningEffort: "low" }
-      }
-      return { store: false, reasoningEffort: "minimal" }
-    }
-    return { store: false }
-  }
-  if (model.providerID === "google") {
-    // gemini-3 uses thinkingLevel, gemini-2.5 uses thinkingBudget
-    return { thinkingConfig: googleSmallThinkingConfig(model.api.id) }
+    const base = { store: false }
+    return mergeDeep(base, small)
   }
   if (model.providerID === "openrouter" || model.providerID === "llmgateway") {
-    if (model.api.id.includes("google")) {
+    if (Object.keys(small).length === 0 && model.api.id.includes("google")) {
       return { reasoning: { enabled: false } }
     }
-    return { reasoningEffort: "minimal" }
   }
 
   if (model.providerID === "venice") {
+    if (Object.keys(small).length > 0) return small
     return { veniceParameters: { disableThinking: true } }
   }
 
-  return {}
+  return small
 }
 
 // Maps model ID prefix to provider slug used in providerOptions.
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index df21922b09..9b6615ee8d 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -3602,8 +3602,8 @@ describe("ProviderTransform.variants", () => {
 })
 
 describe("ProviderTransform.smallOptions - gpt-5 chat/search", () => {
-  const createModel = (apiId: string) =>
-    ({
+  const createModel = (apiId: string) => {
+    const model = {
       id: `openai/${apiId}`,
       providerID: "openai",
       api: {
@@ -3611,13 +3611,43 @@ describe("ProviderTransform.smallOptions - gpt-5 chat/search", () => {
         url: "https://api.openai.com",
         npm: "@ai-sdk/openai",
       },
-    }) as any
+      capabilities: { reasoning: true },
+      limit: { output: 64_000 },
+      release_date: "2026-01-01",
+    } as any
+    model.variants = ProviderTransform.variants(model)
+    return model
+  }
 
   for (const testCase of [
     { id: "gpt-5-chat-latest", options: { store: false } },
-    { id: "gpt-5.1-chat-latest", options: { store: false, reasoningEffort: "medium" } },
-    { id: "gpt-5.2-chat-latest", options: { store: false, reasoningEffort: "medium" } },
-    { id: "gpt-5-search-api", options: { store: false } },
+    {
+      id: "gpt-5.1-chat-latest",
+      options: {
+        store: false,
+        reasoningEffort: "medium",
+        reasoningSummary: "auto",
+        include: ["reasoning.encrypted_content"],
+      },
+    },
+    {
+      id: "gpt-5.2-chat-latest",
+      options: {
+        store: false,
+        reasoningEffort: "medium",
+        reasoningSummary: "auto",
+        include: ["reasoning.encrypted_content"],
+      },
+    },
+    {
+      id: "gpt-5-search-api",
+      options: {
+        store: false,
+        reasoningEffort: "none",
+        reasoningSummary: "auto",
+        include: ["reasoning.encrypted_content"],
+      },
+    },
   ]) {
     test(`${testCase.id} returns only supported small options`, () => {
       expect(ProviderTransform.smallOptions(createModel(testCase.id))).toEqual(testCase.options)
@@ -3626,8 +3656,8 @@ describe("ProviderTransform.smallOptions - gpt-5 chat/search", () => {
 })
 
 describe("ProviderTransform.smallOptions - google thinking controls", () => {
-  const createGoogleModel = (apiId: string) =>
-    ({
+  const createGoogleModel = (apiId: string) => {
+    const model = {
       id: `google/${apiId}`,
       providerID: "google",
       api: {
@@ -3635,20 +3665,44 @@ describe("ProviderTransform.smallOptions - google thinking controls", () => {
         url: "https://generativelanguage.googleapis.com",
         npm: "@ai-sdk/google",
       },
-    }) as any
+      capabilities: { reasoning: true },
+      limit: { output: 64_000 },
+    } as any
+    model.variants = ProviderTransform.variants(model)
+    return model
+  }
 
   for (const testCase of [
-    { id: "gemini-3-pro-preview", options: { thinkingConfig: { thinkingLevel: "low" } } },
-    { id: "gemini-3-flash-preview", options: { thinkingConfig: { thinkingLevel: "minimal" } } },
-    { id: "gemini-3.1-flash-image-preview", options: { thinkingConfig: { thinkingLevel: "minimal" } } },
-    { id: "gemini-3-pro-image-preview", options: { thinkingConfig: { thinkingLevel: "high" } } },
-    { id: "gemini-2.5-pro", options: { thinkingConfig: { thinkingBudget: 128 } } },
-    { id: "gemini-2.5-flash", options: { thinkingConfig: { thinkingBudget: 0 } } },
+    { id: "gemini-3-pro-preview", options: { thinkingConfig: { includeThoughts: true, thinkingLevel: "low" } } },
+    { id: "gemini-3-flash-preview", options: { thinkingConfig: { includeThoughts: true, thinkingLevel: "minimal" } } },
+    {
+      id: "gemini-3.1-flash-image-preview",
+      options: { thinkingConfig: { includeThoughts: true, thinkingLevel: "minimal" } },
+    },
+    { id: "gemini-3-pro-image-preview", options: { thinkingConfig: { includeThoughts: true, thinkingLevel: "high" } } },
+    { id: "gemini-2.5-pro", options: { thinkingConfig: { includeThoughts: true, thinkingBudget: 16000 } } },
+    { id: "gemini-2.5-flash", options: { thinkingConfig: { includeThoughts: true, thinkingBudget: 16000 } } },
   ]) {
     test(`${testCase.id} returns supported small thinking options`, () => {
       expect(ProviderTransform.smallOptions(createGoogleModel(testCase.id))).toEqual(testCase.options)
     })
   }
+
+  test("uses the first configured variant when available", () => {
+    expect(
+      ProviderTransform.smallOptions({
+        ...createGoogleModel("gemini-2.5-pro"),
+        variants: {
+          high: { thinkingConfig: { includeThoughts: true, thinkingBudget: 16000 } },
+          max: { thinkingConfig: { includeThoughts: true, thinkingBudget: 32768 } },
+        },
+      }),
+    ).toEqual({ thinkingConfig: { includeThoughts: true, thinkingBudget: 16000 } })
+  })
+
+  test("does not synthesize thinking options when variants are empty", () => {
+    expect(ProviderTransform.smallOptions({ ...createGoogleModel("gemini-2.5-pro"), variants: {} })).toEqual({})
+  })
 })
 
 describe("ProviderTransform.providerOptions - ai-gateway-provider", () => {