From 49a02e2b956f64554b28546d43238add5d74096c Mon Sep 17 00:00:00 2001
From: Aiden Cline <aidenpcline@gmail.com>
Date: Tue, 30 Jun 2026 17:09:17 -0500
Subject: [PATCH] fix(provider): prefer gemini 2.5 reasoning budgets

---
 packages/opencode/src/provider/transform.ts   | 41 ++++++++++++++-----
 .../opencode/test/provider/transform.test.ts  | 23 ++++++++++-
 2 files changed, 52 insertions(+), 12 deletions(-)

diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 04d14248b1..f505a328f6 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -577,6 +577,14 @@ function googleThinkingLevelVariants() {
   )
 }
 
+function googleThinkingBudgetVariants(budget: ReasoningBudgetOption, model: Provider.Model) {
+  return reasoningBudgetVariants(
+    budget,
+    (thinkingBudget) => ({ thinkingConfig: { includeThoughts: true, thinkingBudget } }),
+    model.limit.output,
+  )
+}
+
 function openAIReasoningEffortVariants() {
   return Object.fromEntries(
     OPENAI_EFFORTS.map((effort) => [
@@ -615,6 +623,25 @@ function reasoningBudgetVariants(
   }
 }
 
+function gemini25BudgetVariants(model: Provider.Model, budget: ReasoningBudgetOption) {
+  // Gemini 2.5 uses numeric thinking budgets in the Google SDK; thinkingLevel is for Gemini 3.
+  if (!idIncludes(model, "gemini-2.5") && !idIncludes(model, "gemini-2-5")) return undefined
+
+  switch (model.api.npm) {
+    case "@ai-sdk/gateway":
+      if (idIncludes(model, "google")) return googleThinkingBudgetVariants(budget, model)
+      return undefined
+
+    case "@ai-sdk/google":
+    case "@ai-sdk/google-vertex":
+      return googleThinkingBudgetVariants(budget, model)
+
+    case "@jerome-benoit/sap-ai-provider-v2":
+      return wrapInSapModelParams(googleThinkingBudgetVariants(budget, model))
+  }
+  return undefined
+}
+
 function anthropicAdaptiveFromOptions(effort: ReasoningEffortOption) {
   return effort.values.includes("max")
 }
@@ -732,6 +759,8 @@ function reasoningOptionVariants(model: Provider.Model): Record<string, Record<s
   if (!model.reasoning_options) return undefined
   const effort = reasoningOption(model, "effort")
   const budget = reasoningOption(model, "budget_tokens")
+  const gemini25Budget = budget ? gemini25BudgetVariants(model, budget) : undefined
+  if (gemini25Budget) return gemini25Budget
 
   if (effort) {
     return Object.fromEntries(
@@ -763,11 +792,7 @@ function reasoningOptionVariants(model: Provider.Model): Record<string, Record<s
         )
       }
       if (idIncludes(model, "google")) {
-        return reasoningBudgetVariants(
-          budget,
-          (thinkingBudget) => ({ thinkingConfig: { includeThoughts: true, thinkingBudget } }),
-          model.limit.output,
-        )
+        return googleThinkingBudgetVariants(budget, model)
       }
       break
 
@@ -787,11 +812,7 @@ function reasoningOptionVariants(model: Provider.Model): Record<string, Record<s
 
     case "@ai-sdk/google":
     case "@ai-sdk/google-vertex":
-      return reasoningBudgetVariants(
-        budget,
-        (thinkingBudget) => ({ thinkingConfig: { includeThoughts: true, thinkingBudget } }),
-        model.limit.output,
-      )
+      return googleThinkingBudgetVariants(budget, model)
 
     case "@jerome-benoit/sap-ai-provider-v2":
       if (model.api.id.includes("anthropic")) {
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index d1230dd6e7..62e8074d0a 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -3220,7 +3220,10 @@ describe("ProviderTransform.variants", () => {
             url: "https://gateway.ai",
             npm: "@ai-sdk/gateway",
           },
-          reasoning_options: [{ type: "budget_tokens", min: 128, max: 32768 }],
+          reasoning_options: [
+            { type: "effort", values: ["minimal", "low", "medium", "high"] },
+            { type: "budget_tokens", min: 128, max: 32768 },
+          ],
         }),
       )
       expect(Object.keys(result)).toEqual(["high", "max"])
@@ -3769,7 +3772,10 @@ describe("ProviderTransform.variants", () => {
                 npm: provider.name,
               },
               reasoning_options: testCase.expectedMax
-                ? [{ type: "budget_tokens", max: testCase.expectedMax.thinkingConfig.thinkingBudget }]
+                ? [
+                    { type: "effort", values: ["minimal", "low", "medium", "high"] },
+                    { type: "budget_tokens", max: testCase.expectedMax.thinkingConfig.thinkingBudget },
+                  ]
                 : [{ type: "effort", values: testCase.efforts }],
             }),
           )
@@ -3866,6 +3872,19 @@ describe("ProviderTransform.variants", () => {
         },
       })
     })
+
+    test("uses reasoning_options budget tokens for Gemini 2.5 variants", () => {
+      const result = ProviderTransform.variants(
+        sapModel("gemini-2.5-pro", [
+          { type: "effort", values: ["minimal", "low", "medium", "high"] },
+          { type: "budget_tokens", min: 128, max: 32768 },
+        ]),
+      )
+      expect(result).toEqual({
+        high: { modelParams: { thinkingConfig: { includeThoughts: true, thinkingBudget: 16_000 } } },
+        max: { modelParams: { thinkingConfig: { includeThoughts: true, thinkingBudget: 32_768 } } },
+      })
+    })
   })
 
   describe("ai-gateway-provider (cloudflare-ai-gateway)", () => {