fix(openrouter): preserve deepseek v4 reasoning replay

CHANGELOG.md

@@ -33,6 +33,7 @@ Docs: https://docs.openclaw.ai
 - Plugins/CLI: cache plugin CLI registration entries per command program so completion state generation does not repeat the full plugin sweep in one invocation. Thanks @ScientificProgrammer.
 - Plugins: reuse gateway-bindable plugin loader cache entries for later default-mode loads without serving default-built registries to gateway-bound requests, reducing repeated plugin registration during dispatch. Refs #61756. Thanks @DmitryPogodaev.
 - Gateway/secrets: include the caught error message in `secrets.reload` and `secrets.resolve` warning logs while keeping RPC errors generic, so operators can diagnose reload and permission failures. Thanks @davidangularme.
+- Providers/OpenRouter: fill DeepSeek V4 `reasoning_content` replay placeholders for `openrouter/deepseek/deepseek-v4-flash` and `openrouter/deepseek/deepseek-v4-pro`, so thinking/tool follow-up turns do not fail with DeepSeek's replay-shape error. Fixes #76018. Thanks @cloph-dsp.
 - Anthropic-compatible streams: recover text deltas that arrive before their matching content block, so Kimi Code and similar providers do not finish as empty `incomplete_result` replies. Fixes #76007. Thanks @vliuyt.
 - fix(infra): block workspace state-directory env override [AI]. (#75940) Thanks @pgondhi987.
 - MCP/OpenAI: normalize parameter-free tool schemas whose top-level object `properties` is missing, null, or invalid before sending tools to OpenAI, so MCP tools without params stay usable. Fixes #75362. Thanks @tolkonepiu and @SymbolStar.

docs/providers/openrouter.md

@@ -174,6 +174,13 @@ does **not** inject those OpenRouter-specific headers or Anthropic cache markers
     return final answer text in reasoning fields for that retired route.
   </Accordion>
 
+  <Accordion title="DeepSeek V4 reasoning replay">
+    On verified OpenRouter routes, `openrouter/deepseek/deepseek-v4-flash` and
+    `openrouter/deepseek/deepseek-v4-pro` fill missing `reasoning_content` on
+    replayed assistant turns so thinking/tool conversations keep DeepSeek V4's
+    required follow-up shape.
+  </Accordion>
+
   <Accordion title="OpenAI-only request shaping">
     OpenRouter still runs through the proxy-style OpenAI-compatible path, so
     native OpenAI-only request shaping such as `serviceTier`, Responses `store`,

extensions/openrouter/index.test.ts

@@ -219,6 +219,127 @@ describe("openrouter provider hooks", () => {
     expect(baseStreamFn).toHaveBeenCalledOnce();
   });
 
+  it("fills DeepSeek V4 reasoning_content for OpenRouter replay turns", async () => {
+    const provider = await registerSingleProviderPlugin(openrouterPlugin);
+    let capturedPayload: Record<string, unknown> | undefined;
+    const baseStreamFn = vi.fn(
+      (
+        ...args: Parameters<import("@mariozechner/pi-agent-core").StreamFn>
+      ): ReturnType<import("@mariozechner/pi-agent-core").StreamFn> => {
+        const payload = {
+          messages: [
+            { role: "user", content: "read file" },
+            { role: "assistant", tool_calls: [{ id: "call_1", type: "function" }] },
+            { role: "tool", content: "ok" },
+            { role: "assistant", content: "done" },
+          ],
+        };
+        void args[2]?.onPayload?.(payload, args[0]);
+        capturedPayload = payload;
+        return { async *[Symbol.asyncIterator]() {} } as never;
+      },
+    );
+
+    const wrapped = provider.wrapStreamFn?.({
+      provider: "openrouter",
+      modelId: "deepseek/deepseek-v4-flash",
+      streamFn: baseStreamFn,
+      thinkingLevel: "xhigh",
+    } as never);
+
+    void wrapped?.(
+      {
+        provider: "openrouter",
+        api: "openai-completions",
+        id: "deepseek/deepseek-v4-flash",
+        baseUrl: "https://openrouter.ai/api/v1",
+        compat: {},
+      } as never,
+      { messages: [] } as never,
+      {},
+    );
+
+    expect(capturedPayload).toMatchObject({
+      thinking: { type: "enabled" },
+      reasoning_effort: "max",
+      messages: [
+        { role: "user", content: "read file" },
+        {
+          role: "assistant",
+          tool_calls: [{ id: "call_1", type: "function" }],
+          reasoning_content: "",
+        },
+        { role: "tool", content: "ok" },
+        { role: "assistant", content: "done", reasoning_content: "" },
+      ],
+    });
+    expect(baseStreamFn).toHaveBeenCalledOnce();
+  });
+
+  it("recognizes full OpenRouter DeepSeek V4 refs but skips custom proxy routes", async () => {
+    const provider = await registerSingleProviderPlugin(openrouterPlugin);
+    const payloads: Array<Record<string, unknown>> = [];
+    const baseStreamFn = vi.fn(
+      (
+        ...args: Parameters<import("@mariozechner/pi-agent-core").StreamFn>
+      ): ReturnType<import("@mariozechner/pi-agent-core").StreamFn> => {
+        const payload = {
+          messages: [{ role: "assistant", tool_calls: [{ id: "call_1", type: "function" }] }],
+        };
+        void args[2]?.onPayload?.(payload, args[0]);
+        payloads.push(payload);
+        return { async *[Symbol.asyncIterator]() {} } as never;
+      },
+    );
+
+    const fullRef = provider.wrapStreamFn?.({
+      provider: "openrouter",
+      modelId: "openrouter/deepseek/deepseek-v4-pro",
+      streamFn: baseStreamFn,
+      thinkingLevel: "high",
+    } as never);
+    void fullRef?.(
+      {
+        provider: "openrouter",
+        api: "openai-completions",
+        id: "openrouter/deepseek/deepseek-v4-pro",
+        baseUrl: "https://openrouter.ai/api/v1",
+        compat: {},
+      } as never,
+      { messages: [] } as never,
+      {},
+    );
+
+    const customRoute = provider.wrapStreamFn?.({
+      provider: "openrouter",
+      modelId: "deepseek/deepseek-v4-pro",
+      streamFn: baseStreamFn,
+      thinkingLevel: "high",
+    } as never);
+    void customRoute?.(
+      {
+        provider: "openrouter",
+        api: "openai-completions",
+        id: "deepseek/deepseek-v4-pro",
+        baseUrl: "https://proxy.example.com/v1",
+        compat: {},
+      } as never,
+      { messages: [] } as never,
+      {},
+    );
+
+    expect(payloads[0]?.messages).toEqual([
+      {
+        role: "assistant",
+        tool_calls: [{ id: "call_1", type: "function" }],
+        reasoning_content: "",
+      },
+    ]);
+    expect(payloads[1]?.messages).toEqual([
+      { role: "assistant", tool_calls: [{ id: "call_1", type: "function" }] },
+    ]);
+  });
+
   it("strips OpenRouter-routed Anthropic assistant prefill when reasoning is enabled", async () => {
     const provider = await registerSingleProviderPlugin(openrouterPlugin);
     let capturedPayload: Record<string, unknown> | undefined;

extensions/openrouter/stream.ts

@@ -2,6 +2,7 @@ import type { StreamFn } from "@mariozechner/pi-agent-core";
 import type { ProviderWrapStreamFnContext } from "openclaw/plugin-sdk/plugin-entry";
 import { OPENROUTER_THINKING_STREAM_HOOKS } from "openclaw/plugin-sdk/provider-stream-family";
 import {
+  createDeepSeekV4OpenAICompatibleThinkingWrapper,
   createPayloadPatchStreamWrapper,
   stripTrailingAssistantPrefillMessages,
 } from "openclaw/plugin-sdk/provider-stream-shared";
@@ -26,6 +27,22 @@ function isOpenRouterAnthropicModelId(modelId: unknown): boolean {
   );
 }
 
+function normalizeOpenRouterModelId(modelId: unknown): string | undefined {
+  const normalized = readString(modelId)?.toLowerCase();
+  return normalized?.startsWith("openrouter/")
+    ? normalized.slice("openrouter/".length)
+    : normalized;
+}
+
+function isOpenRouterDeepSeekV4ModelId(modelId: unknown): boolean {
+  const normalized = normalizeOpenRouterModelId(modelId);
+  if (!normalized?.startsWith("deepseek/")) {
+    return false;
+  }
+  const deepSeekModelId = normalized.slice("deepseek/".length).split(":", 1)[0];
+  return deepSeekModelId === "deepseek-v4-flash" || deepSeekModelId === "deepseek-v4-pro";
+}
+
 function isVerifiedOpenRouterRoute(model: Parameters<StreamFn>[0]): boolean {
   const provider = readString(model.provider)?.toLowerCase();
   const baseUrl = readString(model.baseUrl);
@@ -44,6 +61,15 @@ function shouldPatchAnthropicOpenRouterPayload(model: Parameters<StreamFn>[0]):
   );
 }
 
+function shouldPatchDeepSeekV4OpenRouterPayload(model: Parameters<StreamFn>[0]): boolean {
+  const api = readString(model.api);
+  return (
+    (api === undefined || api === "openai-completions") &&
+    isOpenRouterDeepSeekV4ModelId(model.id) &&
+    isVerifiedOpenRouterRoute(model)
+  );
+}
+
 function isEnabledReasoningValue(value: unknown): boolean {
   if (value === undefined || value === null || value === false) {
     return false;
@@ -106,6 +132,17 @@ function createOpenRouterAnthropicPrefillWrapper(baseStreamFn: StreamFn | undefi
   );
 }
 
+function createOpenRouterDeepSeekV4ThinkingWrapper(
+  baseStreamFn: StreamFn | undefined,
+  thinkingLevel: ProviderWrapStreamFnContext["thinkingLevel"],
+): StreamFn | undefined {
+  return createDeepSeekV4OpenAICompatibleThinkingWrapper({
+    baseStreamFn,
+    thinkingLevel,
+    shouldPatchModel: shouldPatchDeepSeekV4OpenRouterPayload,
+  });
+}
+
 export function wrapOpenRouterProviderStream(
   ctx: ProviderWrapStreamFnContext,
 ): StreamFn | null | undefined {
@@ -118,7 +155,9 @@ export function wrapOpenRouterProviderStream(
     : ctx.streamFn;
   const wrapStreamFn = OPENROUTER_THINKING_STREAM_HOOKS.wrapStreamFn ?? undefined;
   if (!wrapStreamFn) {
-    return createOpenRouterAnthropicPrefillWrapper(routedStreamFn);
+    return createOpenRouterAnthropicPrefillWrapper(
+      createOpenRouterDeepSeekV4ThinkingWrapper(routedStreamFn, ctx.thinkingLevel),
+    );
   }
   const wrappedStreamFn =
     wrapStreamFn({
@@ -128,12 +167,16 @@ export function wrapOpenRouterProviderStream(
         ? undefined
         : ctx.thinkingLevel,
     }) ?? undefined;
-  return createOpenRouterAnthropicPrefillWrapper(wrappedStreamFn);
+  return createOpenRouterAnthropicPrefillWrapper(
+    createOpenRouterDeepSeekV4ThinkingWrapper(wrappedStreamFn, ctx.thinkingLevel),
+  );
 }
 
 export const __testing = {
+  isOpenRouterDeepSeekV4ModelId,
   isOpenRouterAnthropicModelId,
   isOpenRouterReasoningPayloadEnabled,
   isVerifiedOpenRouterRoute,
+  shouldPatchDeepSeekV4OpenRouterPayload,
   shouldPatchAnthropicOpenRouterPayload,
 };