diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index f42e14139f1e..ff81c8805691 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -861,13 +861,28 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
     case "venice-ai-sdk-provider":
     // https://docs.venice.ai/overview/guides/reasoning-models#reasoning-effort
     case "@ai-sdk/openai-compatible":
+      // North Mini Code models only support "none" and "high" reasoning effort levels.
       if (model.api.id.toLowerCase().includes("north-mini-code")) {
         return Object.fromEntries(["none", "high"].map((effort) => [effort, { reasoningEffort: effort }]))
       }
-      const efforts = [...WIDELY_SUPPORTED_EFFORTS]
+
+      // Add none and max variants to deepseek-v4 models. None is only added to the official
+      // Deepseek provider because others may not support it. 
       if (model.api.id.toLowerCase().includes("deepseek-v4")) {
-        efforts.push("max")
+        const efforts = [...WIDELY_SUPPORTED_EFFORTS, "max"]
+        if (model.providerID === "deepseek") efforts.unshift("none")
+        return Object.fromEntries(
+          efforts.map((effort) => [
+            effort,
+            effort === "none"
+              ? { thinking: { type: "disabled" } }
+              : { reasoningEffort: effort },
+          ])
+        )
       }
+
+      // Use the widely supported levels for all other models using this API.
+      const efforts = [...WIDELY_SUPPORTED_EFFORTS]
       return Object.fromEntries(efforts.map((effort) => [effort, { reasoningEffort: effort }]))
 
     case "@ai-sdk/azure":
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index 7307e3f60b7e..5f3e65e225a2 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -1,4 +1,6 @@
 import { describe, expect, test } from "bun:test"
+import { generateText } from "ai"
+import { createOpenAICompatible } from "@ai-sdk/openai-compatible"
 import { Effect } from "effect"
 import { ProviderTransform } from "@/provider/transform"
 import { LLMRequestPrep } from "@/session/llm/request"
@@ -3798,6 +3800,49 @@ describe("ProviderTransform.variants", () => {
         high: { reasoningEffort: "high" },
       })
     })
+
+    test("deepseek-v4 none disables thinking on the wire", async () => {
+      const model = createMockModel({
+        id: "deepseek/deepseek-v4-pro",
+        providerID: "deepseek",
+        api: {
+          id: "deepseek-v4-pro",
+          url: "https://api.deepseek.com",
+          npm: "@ai-sdk/openai-compatible",
+        },
+      })
+      let body: Record<string, unknown> | undefined
+      const deepseek = createOpenAICompatible({
+        name: "deepseek",
+        baseURL: model.api.url,
+        apiKey: "test",
+        fetch: Object.assign(
+          async (_input: Parameters<typeof fetch>[0], init?: Parameters<typeof fetch>[1]) => {
+            body = JSON.parse(String(init?.body))
+            return new Response(
+              JSON.stringify({
+                id: "chatcmpl-test",
+                object: "chat.completion",
+                created: 0,
+                model: model.api.id,
+                choices: [{ index: 0, message: { role: "assistant", content: "ok" }, finish_reason: "stop" }],
+                usage: { prompt_tokens: 1, completion_tokens: 1, total_tokens: 2 },
+              }),
+              { headers: { "Content-Type": "application/json" } },
+            )
+          },
+          { preconnect: fetch.preconnect.bind(fetch) },
+        ),
+      })
+
+      await generateText({
+        model: deepseek(model.api.id),
+        prompt: "hi",
+        providerOptions: ProviderTransform.providerOptions(model, ProviderTransform.variants(model).none),
+      })
+
+      expect(body?.thinking).toEqual({ type: "disabled" })
+    })
   })
 
   describe("@ai-sdk/azure", () => {