fix: deepseek reasoning_content round-tripping on openrouter

.changeset/openrouter-deepseek-reasoning.md

@@ -0,0 +1,6 @@
+---
+"@kilocode/cli": patch
+"@kilocode/kilo-gateway": patch
+---
+
+Fix multi-turn DeepSeek reasoning round-tripping on OpenRouter by bumping `@openrouter/ai-sdk-provider` to 2.8.1 in both the CLI and Kilo Gateway packages and letting the SDK handle reasoning details, plus pulling in upstream DeepSeek variant, reasoning-effort, and assistant-reasoning fixes. New DeepSeek conversations are fixed; existing sessions that already stored empty reasoning metadata may still need to be restarted.

packages/kilo-gateway/package.json

@@ -33,7 +33,7 @@
     "@ai-sdk/anthropic": "3.0.71",
     "@ai-sdk/openai": "3.0.48",
     "@ai-sdk/openai-compatible": "2.0.37",
-    "@openrouter/ai-sdk-provider": "2.5.1",
+    "@openrouter/ai-sdk-provider": "2.8.1",
     "@clack/prompts": "1.0.0-alpha.1",
     "ai": "catalog:",
     "open": "10.1.2",

packages/opencode/package.json

@@ -121,7 +121,7 @@
     "@octokit/rest": "catalog:",
     "@openauthjs/openauth": "catalog:",
     "@opencode-ai/script": "workspace:*",
-    "@openrouter/ai-sdk-provider": "2.5.1",
+    "@openrouter/ai-sdk-provider": "2.8.1",
     "@opentelemetry/api": "1.9.0",
     "@opentelemetry/context-async-hooks": "2.6.1",
     "@opentelemetry/exporter-trace-otlp-http": "0.214.0",

packages/opencode/src/provider/transform.ts

@@ -183,7 +183,34 @@ function normalizeMessages(
     return result
   }
 
-  if (typeof model.capabilities.interleaved === "object" && model.capabilities.interleaved.field) {
+  // kilocode_change start - cherry-picked from anomalyco/opencode#24180;
+  // will be reverted on the next wholesale upstream merge.
+  // Deepseek requires all assistant messages to have reasoning on them
+  if (model.api.id.includes("deepseek")) {
+    msgs = msgs.map((msg) => {
+      if (msg.role !== "assistant") return msg
+      if (Array.isArray(msg.content)) {
+        if (msg.content.some((part) => part.type === "reasoning")) return msg
+        return { ...msg, content: [...msg.content, { type: "reasoning", text: "" }] }
+      }
+      return {
+        ...msg,
+        content: [
+          ...(msg.content ? [{ type: "text" as const, text: msg.content }] : []),
+          { type: "reasoning" as const, text: "" },
+        ],
+      }
+    })
+  }
+  // kilocode_change end
+
+  // kilocode_change start - cherry-picked from anomalyco/opencode#24435
+  if (
+    typeof model.capabilities.interleaved === "object" &&
+    model.capabilities.interleaved.field &&
+    model.api.npm !== "@openrouter/ai-sdk-provider"
+  ) {
+    // kilocode_change end
     const field = model.capabilities.interleaved.field
     return msgs.map((msg) => {
       if (msg.role === "assistant" && Array.isArray(msg.content)) {
@@ -425,7 +452,12 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
   const adaptiveEfforts = anthropicAdaptiveEfforts(model.api.id)
 
   if (
-    id.includes("deepseek") ||
+    // kilocode_change start - cherry-picked from anomalyco/opencode#24157
+    id.includes("deepseek-chat") ||
+    id.includes("deepseek-reasoner") ||
+    id.includes("deepseek-r1") ||
+    id.includes("deepseek-v3") ||
+    // kilocode_change end
     id.includes("minimax") ||
     // id.includes("glm") || // kilocode_change
     id.includes("mistral") ||
@@ -569,7 +601,13 @@ 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":
-      return Object.fromEntries(WIDELY_SUPPORTED_EFFORTS.map((effort) => [effort, { reasoningEffort: effort }]))
+      // kilocode_change start - cherry-picked from anomalyco/opencode#24163
+      const efforts = [...WIDELY_SUPPORTED_EFFORTS]
+      if (model.api.id.includes("deepseek-v4")) {
+        efforts.push("max")
+      }
+      return Object.fromEntries(efforts.map((effort) => [effort, { reasoningEffort: effort }]))
+    // kilocode_change end
 
     case "@ai-sdk/azure":
       // https://v5.ai-sdk.dev/providers/ai-sdk-providers/azure

packages/opencode/test/session/message-v2.test.ts

@@ -803,6 +803,81 @@ describe("session.message-v2.toModelMessage", () => {
     ])
   })
 
+  // kilocode_change start - cherry-picked from anomalyco/opencode#24435
+  test("preserves OpenRouter reasoning details through provider transform", async () => {
+    const assistantID = "m-assistant"
+    const openrouterModel: Provider.Model = {
+      ...model,
+      id: ModelID.make("deepseek/deepseek-v4-pro"),
+      providerID: ProviderID.make("openrouter"),
+      api: {
+        id: "deepseek/deepseek-v4-pro",
+        url: "https://openrouter.ai/api/v1",
+        npm: "@openrouter/ai-sdk-provider",
+      },
+      capabilities: {
+        ...model.capabilities,
+        reasoning: true,
+        interleaved: { field: "reasoning_details" },
+      },
+    }
+    const reasoningDetails = [
+      {
+        type: "reasoning.text",
+        text: "thinking",
+        format: "unknown",
+        index: 0,
+      },
+    ]
+    const input: MessageV2.WithParts[] = [
+      {
+        info: assistantInfo(assistantID, "m-parent", undefined, {
+          providerID: openrouterModel.providerID,
+          modelID: openrouterModel.id,
+        }),
+        parts: [
+          {
+            ...basePart(assistantID, "a1"),
+            type: "reasoning",
+            text: "thinking",
+            time: { start: 0 },
+            metadata: {
+              openrouter: {
+                reasoning_details: reasoningDetails,
+              },
+            },
+          },
+          {
+            ...basePart(assistantID, "a2"),
+            type: "text",
+            text: "answer",
+          },
+        ] as MessageV2.Part[],
+      },
+    ]
+
+    expect(
+      ProviderTransform.message(await MessageV2.toModelMessages(input, openrouterModel), openrouterModel, {}),
+    ).toStrictEqual([
+      {
+        role: "assistant",
+        content: [
+          {
+            type: "reasoning",
+            text: "thinking",
+            providerOptions: {
+              openrouter: {
+                reasoning_details: reasoningDetails,
+              },
+            },
+          },
+          { type: "text", text: "answer" },
+        ],
+      },
+    ])
+  })
+  // kilocode_change end
+
   test("splits assistant messages on step-start boundaries", async () => {
     const assistantID = "m-assistant"