diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 9d98815cdad5..00d8873b8a23 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -551,6 +551,8 @@ export function topP(model: Provider.Model) {
   if (["minimax-m2", "kimi-k2.5", "kimi-k2p5", "kimi-k2-5"].some((s) => id.includes(s))) {
     return 0.95
   }
+  // https://huggingface.co/deepseek-ai/DeepSeek-V4-Flash-0731
+  if (id.includes("deepseek-v4-flash")) return 0.95
   return undefined
 }
 
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index 9897c543fb81..f306d97d9902 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -3272,6 +3272,18 @@ describe("ProviderTransform sampling defaults - Gemini", () => {
   })
 })
 
+describe("ProviderTransform sampling defaults - DeepSeek", () => {
+  test("defaults deepseek-v4-flash top_p to 0.95", () => {
+    const model = {
+      id: "deepseek/deepseek-v4-flash",
+      api: { id: "deepseek-v4-flash" },
+    } as any
+    expect(ProviderTransform.temperature(model)).toBeUndefined()
+    expect(ProviderTransform.topP(model)).toBe(0.95)
+    expect(ProviderTransform.topK(model)).toBeUndefined()
+  })
+})
+
 describe("ProviderTransform.reasoningVariants", () => {
   const model = (reasoning_options: ModelsDev.Model["reasoning_options"]) => ({ reasoning_options }) as ModelsDev.Model
   const target = (npm: string, id = "test-model") =>