diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe9af6ea21b..052509381bf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -87,6 +87,7 @@ Docs: https://docs.openclaw.ai
 - Providers/OpenAI-compatible: forward `prompt_cache_key` on Completions requests only for providers that opt in with `compat.supportsPromptCacheKey`, keeping default proxy payloads unchanged. Fixes #69272.
 - Providers/OpenAI-compatible: skip null or non-object streaming chunks from custom providers instead of failing the turn after partial output. Fixes #51112.
 - Providers/OpenAI-compatible: treat singular MLX-style `finish_reason: "tool_call"` as tool use instead of a provider error. Fixes #61499.
+- Plugins/OpenCode: strip unsupported disabled Responses reasoning payloads for OpenCode image understanding. Fixes #70252.
 - Providers/ElevenLabs: omit the MP3-only `Accept` header for PCM telephony synthesis, so Voice Call requests for `pcm_22050` no longer receive MP3 audio. Fixes #67340. Thanks @marcchabot.
 - Providers/MiniMax TTS: mark MP3 output voice-compatible for Telegram voice-note delivery. Fixes #63540.
 - Providers/Microsoft TTS: keep allowlisted bundled speech providers discoverable even when another speech plugin has already registered, so Edge/Microsoft TTS is available alongside OpenAI. Fixes #62117 and #66850.
diff --git a/extensions/opencode/index.test.ts b/extensions/opencode/index.test.ts
index ff59311b196..7172f76023c 100644
--- a/extensions/opencode/index.test.ts
+++ b/extensions/opencode/index.test.ts
@@ -1,8 +1,29 @@
-import { describe, it } from "vitest";
+import { describe, expect, it } from "vitest";
+import { registerProviderPlugin } from "../../test/helpers/plugins/provider-registration.js";
 import { expectPassthroughReplayPolicy } from "../../test/helpers/provider-replay-policy.ts";
 import plugin from "./index.js";
 
 describe("opencode provider plugin", () => {
+  it("registers image media understanding through the OpenCode plugin", async () => {
+    const { mediaProviders } = await registerProviderPlugin({
+      plugin,
+      id: "opencode",
+      name: "OpenCode Zen Provider",
+    });
+
+    expect(mediaProviders).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          id: "opencode",
+          capabilities: ["image"],
+          defaultModels: { image: "gpt-5-nano" },
+          describeImage: expect.any(Function),
+          describeImages: expect.any(Function),
+        }),
+      ]),
+    );
+  });
+
   it("owns passthrough-gemini replay policy for Gemini-backed models", async () => {
     await expectPassthroughReplayPolicy({
       plugin,
diff --git a/extensions/opencode/index.ts b/extensions/opencode/index.ts
index c7ba3e8f8d9..1e97b81e160 100644
--- a/extensions/opencode/index.ts
+++ b/extensions/opencode/index.ts
@@ -6,6 +6,7 @@ import {
 } from "openclaw/plugin-sdk/provider-model-shared";
 import { normalizeLowercaseStringOrEmpty } from "openclaw/plugin-sdk/text-runtime";
 import { applyOpencodeZenConfig, OPENCODE_ZEN_DEFAULT_MODEL } from "./api.js";
+import { opencodeMediaUnderstandingProvider } from "./media-understanding-provider.js";
 
 const PROVIDER_ID = "opencode";
 const MINIMAX_MODERN_MODEL_MATCHERS = ["minimax-m2.7"] as const;
@@ -49,5 +50,6 @@ export default definePluginEntry({
       ...PASSTHROUGH_GEMINI_REPLAY_HOOKS,
       isModernModelRef: ({ modelId }) => isModernOpencodeModel(modelId),
     });
+    api.registerMediaUnderstandingProvider(opencodeMediaUnderstandingProvider);
   },
 });
diff --git a/extensions/opencode/media-understanding-provider.test.ts b/extensions/opencode/media-understanding-provider.test.ts
new file mode 100644
index 00000000000..1fc34012dac
--- /dev/null
+++ b/extensions/opencode/media-understanding-provider.test.ts
@@ -0,0 +1,48 @@
+import { describe, expect, it } from "vitest";
+import {
+  opencodeMediaUnderstandingProvider,
+  stripOpencodeDisabledResponsesReasoningPayload,
+} from "./media-understanding-provider.js";
+
+describe("opencode media understanding provider", () => {
+  it("strips disabled Responses reasoning payloads", () => {
+    const payload = {
+      reasoning: { effort: "none" },
+      include: ["reasoning.encrypted_content"],
+      store: false,
+    };
+
+    stripOpencodeDisabledResponsesReasoningPayload(payload);
+
+    expect(payload).toEqual({
+      include: ["reasoning.encrypted_content"],
+      store: false,
+    });
+  });
+
+  it("keeps supported Responses reasoning payloads", () => {
+    const payload = {
+      reasoning: { effort: "low" },
+      store: false,
+    };
+
+    stripOpencodeDisabledResponsesReasoningPayload(payload);
+
+    expect(payload).toEqual({
+      reasoning: { effort: "low" },
+      store: false,
+    });
+  });
+
+  it("declares OpenCode image understanding support", () => {
+    expect(opencodeMediaUnderstandingProvider).toEqual(
+      expect.objectContaining({
+        id: "opencode",
+        capabilities: ["image"],
+        defaultModels: { image: "gpt-5-nano" },
+        describeImage: expect.any(Function),
+        describeImages: expect.any(Function),
+      }),
+    );
+  });
+});
diff --git a/extensions/opencode/media-understanding-provider.ts b/extensions/opencode/media-understanding-provider.ts
new file mode 100644
index 00000000000..cd389153552
--- /dev/null
+++ b/extensions/opencode/media-understanding-provider.ts
@@ -0,0 +1,42 @@
+import type { ProviderStreamOptions } from "@mariozechner/pi-ai";
+import {
+  describeImageWithModelPayloadTransform,
+  describeImagesWithModelPayloadTransform,
+  type MediaUnderstandingProvider,
+} from "openclaw/plugin-sdk/media-understanding";
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return Boolean(value) && typeof value === "object" && !Array.isArray(value);
+}
+
+export function stripOpencodeDisabledResponsesReasoningPayload(payload: unknown): void {
+  if (!isRecord(payload)) {
+    return;
+  }
+  const reasoning = payload.reasoning;
+  if (reasoning === "none") {
+    delete payload.reasoning;
+    return;
+  }
+  if (!isRecord(reasoning) || reasoning.effort !== "none") {
+    return;
+  }
+  delete payload.reasoning;
+}
+
+const stripDisabledResponsesReasoning: ProviderStreamOptions["onPayload"] = (payload) => {
+  stripOpencodeDisabledResponsesReasoningPayload(payload);
+  return undefined;
+};
+
+export const opencodeMediaUnderstandingProvider: MediaUnderstandingProvider = {
+  id: "opencode",
+  capabilities: ["image"],
+  defaultModels: {
+    image: "gpt-5-nano",
+  },
+  describeImage: (request) =>
+    describeImageWithModelPayloadTransform(request, stripDisabledResponsesReasoning),
+  describeImages: (request) =>
+    describeImagesWithModelPayloadTransform(request, stripDisabledResponsesReasoning),
+};
diff --git a/src/media-understanding/image-runtime.ts b/src/media-understanding/image-runtime.ts
index d04f850ff1b..b0c5c82c8f6 100644
--- a/src/media-understanding/image-runtime.ts
+++ b/src/media-understanding/image-runtime.ts
@@ -7,3 +7,9 @@ export const describeImageWithModel = bindImageRuntime((runtime) => runtime.desc
 export const describeImagesWithModel = bindImageRuntime(
   (runtime) => runtime.describeImagesWithModel,
 );
+export const describeImageWithModelPayloadTransform = bindImageRuntime(
+  (runtime) => runtime.describeImageWithModelPayloadTransform,
+);
+export const describeImagesWithModelPayloadTransform = bindImageRuntime(
+  (runtime) => runtime.describeImagesWithModelPayloadTransform,
+);
diff --git a/src/media-understanding/image.ts b/src/media-understanding/image.ts
index 83073871b16..261fdb9b8a4 100644
--- a/src/media-understanding/image.ts
+++ b/src/media-understanding/image.ts
@@ -95,6 +95,38 @@ function isImageModelNoTextError(err: unknown): boolean {
   return err instanceof Error && /^Image model returned no text\b/.test(err.message);
 }
 
+function isPromiseLike(value: unknown): value is PromiseLike<unknown> {
+  return Boolean(value) && typeof (value as { then?: unknown }).then === "function";
+}
+
+function composeImageDescriptionPayloadHandlers(
+  first: ProviderStreamOptions["onPayload"] | undefined,
+  second: ProviderStreamOptions["onPayload"] | undefined,
+): ProviderStreamOptions["onPayload"] | undefined {
+  if (!first) {
+    return second;
+  }
+  if (!second) {
+    return first;
+  }
+  return (payload, payloadModel) => {
+    const runSecond = (firstResult: unknown) => {
+      const nextPayload = firstResult === undefined ? payload : firstResult;
+      const secondResult = second(nextPayload, payloadModel);
+      const coerceResult = (resolvedSecond: unknown) =>
+        resolvedSecond === undefined ? firstResult : resolvedSecond;
+      return isPromiseLike(secondResult)
+        ? Promise.resolve(secondResult).then(coerceResult)
+        : coerceResult(secondResult);
+    };
+    const firstResult = first(payload, payloadModel);
+    if (isPromiseLike(firstResult)) {
+      return Promise.resolve(firstResult).then(runSecond);
+    }
+    return runSecond(firstResult);
+  };
+}
+
 async function resolveImageRuntime(params: {
   cfg: ImageDescriptionRequest["cfg"];
   agentDir: string;
@@ -231,8 +263,9 @@ async function resolveMinimaxVlmFallbackRuntime(params: {
   };
 }
 
-export async function describeImagesWithModel(
+async function describeImagesWithModelInternal(
   params: ImagesDescriptionRequest,
+  options: { onPayload?: ProviderStreamOptions["onPayload"] } = {},
 ): Promise<ImagesDescriptionResult> {
   const prompt = params.prompt ?? "Describe the image.";
   let apiKey: string;
@@ -284,13 +317,15 @@ export async function describeImagesWithModel(
       : undefined;
 
   const maxTokens = resolveImageToolMaxTokens(model.maxTokens, params.maxTokens ?? 512);
-  const completeImage = async (onPayload?: ProviderStreamOptions["onPayload"]) =>
-    await complete(model, context, {
+  const completeImage = async (onPayload?: ProviderStreamOptions["onPayload"]) => {
+    const payloadHandler = composeImageDescriptionPayloadHandlers(onPayload, options.onPayload);
+    return await complete(model, context, {
       apiKey,
       maxTokens,
       signal: controller.signal,
-      ...(onPayload ? { onPayload } : {}),
+      ...(payloadHandler ? { onPayload: payloadHandler } : {}),
     });
+  };
 
   try {
     const message = await completeImage();
@@ -319,6 +354,19 @@ export async function describeImagesWithModel(
   }
 }
 
+export async function describeImagesWithModel(
+  params: ImagesDescriptionRequest,
+): Promise<ImagesDescriptionResult> {
+  return await describeImagesWithModelInternal(params);
+}
+
+export async function describeImagesWithModelPayloadTransform(
+  params: ImagesDescriptionRequest,
+  onPayload: ProviderStreamOptions["onPayload"],
+): Promise<ImagesDescriptionResult> {
+  return await describeImagesWithModelInternal(params, { onPayload });
+}
+
 export async function describeImageWithModel(
   params: ImageDescriptionRequest,
 ): Promise<ImageDescriptionResult> {
@@ -342,3 +390,31 @@ export async function describeImageWithModel(
     cfg: params.cfg,
   });
 }
+
+export async function describeImageWithModelPayloadTransform(
+  params: ImageDescriptionRequest,
+  onPayload: ProviderStreamOptions["onPayload"],
+): Promise<ImageDescriptionResult> {
+  return await describeImagesWithModelPayloadTransform(
+    {
+      images: [
+        {
+          buffer: params.buffer,
+          fileName: params.fileName,
+          mime: params.mime,
+        },
+      ],
+      model: params.model,
+      provider: params.provider,
+      prompt: params.prompt,
+      maxTokens: params.maxTokens,
+      timeoutMs: params.timeoutMs,
+      profile: params.profile,
+      preferredProfile: params.preferredProfile,
+      authStore: params.authStore,
+      agentDir: params.agentDir,
+      cfg: params.cfg,
+    },
+    onPayload,
+  );
+}
diff --git a/src/plugin-sdk/media-understanding.ts b/src/plugin-sdk/media-understanding.ts
index 2fc4399b77d..07c7b360c37 100644
--- a/src/plugin-sdk/media-understanding.ts
+++ b/src/plugin-sdk/media-understanding.ts
@@ -15,7 +15,9 @@ export type {
 
 export {
   describeImageWithModel,
+  describeImageWithModelPayloadTransform,
   describeImagesWithModel,
+  describeImagesWithModelPayloadTransform,
 } from "../media-understanding/image-runtime.js";
 export {
   buildOpenAiCompatibleVideoRequestBody,