diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 04d14248b1..4eee1cf321 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -590,6 +590,10 @@ function openAIReasoningEffortVariants() {
   )
 }
 
+function openAICompatibleReasoningEffortVariants() {
+  return Object.fromEntries(OPENAI_EFFORTS.map((effort) => [effort, { reasoningEffort: effort }]))
+}
+
 type ReasoningOption = NonNullable<Provider.Model["reasoning_options"]>[number]
 type ReasoningEffortOption = Extract<ReasoningOption, { type: "effort" }>
 type ReasoningBudgetOption = Extract<ReasoningOption, { type: "budget_tokens" }>
@@ -828,6 +832,7 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
       return Object.fromEntries(WIDELY_SUPPORTED_EFFORTS.map((effort) => [effort, { reasoning: { effort } }]))
 
     case "ai-gateway-provider":
+      if (idIncludes(model, "openai")) return openAICompatibleReasoningEffortVariants()
       return Object.fromEntries(WIDELY_SUPPORTED_EFFORTS.map((effort) => [effort, { reasoningEffort: effort }]))
 
     case "@ai-sdk/gateway":
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index d1230dd6e7..c0146051a0 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -3881,12 +3881,15 @@ describe("ProviderTransform.variants", () => {
         release_date: releaseDate,
       })
 
-    test("falls back to widely-supported OAI efforts", () => {
+    test("OpenAI upstreams fall back to broad OAI efforts", () => {
       const result = ProviderTransform.variants(cfModel("openai/gpt-future", "2026-03-05"))
       expect(result).toEqual({
+        none: { reasoningEffort: "none" },
+        minimal: { reasoningEffort: "minimal" },
         low: { reasoningEffort: "low" },
         medium: { reasoningEffort: "medium" },
         high: { reasoningEffort: "high" },
+        xhigh: { reasoningEffort: "xhigh" },
       })
     })
 
diff --git a/packages/opencode/test/tool/read.test.ts b/packages/opencode/test/tool/read.test.ts
index c1ef61b227..c0414f6c6a 100644
--- a/packages/opencode/test/tool/read.test.ts
+++ b/packages/opencode/test/tool/read.test.ts
@@ -316,9 +316,7 @@ describe("tool.read truncation", () => {
   it.instance("truncates large file by bytes and sets truncated metadata", () =>
     Effect.gen(function* () {
       const test = yield* TestInstance
-      const base = yield* load(path.join(FIXTURES_DIR, "models-api.json"))
-      const target = 60 * 1024
-      const content = base.length >= target ? base : base.repeat(Math.ceil(target / base.length))
+      const content = `${"x".repeat(80)}\n`.repeat(1_000)
       yield* put(path.join(test.directory, "large.json"), content)
 
       const result = yield* run({ filePath: path.join(test.directory, "large.json") })
diff --git a/packages/opencode/test/tool/truncation.test.ts b/packages/opencode/test/tool/truncation.test.ts
index d575a58ffa..e6ef0693ea 100644
--- a/packages/opencode/test/tool/truncation.test.ts
+++ b/packages/opencode/test/tool/truncation.test.ts
@@ -163,8 +163,7 @@ describe("Truncate", () => {
     it.live("large single-line file truncates with byte message", () =>
       Effect.gen(function* () {
         const svc = yield* Truncate.Service
-        const fsys = yield* FSUtil.Service
-        const content = yield* fsys.readFileString(path.join(FIXTURES_DIR, "models-api.json"))
+        const content = "a".repeat(Truncate.MAX_BYTES + 1)
         const result = yield* svc.output(content)
 
         expect(result.truncated).toBe(true)