fix(provider): preserve Mistral reasoning history (#38453)

packages/opencode/package.json

@@ -66,7 +66,7 @@
     "@ai-sdk/google": "3.0.73",
     "@ai-sdk/google-vertex": "4.0.128",
     "@ai-sdk/groq": "3.0.31",
-    "@ai-sdk/mistral": "3.0.34",
+    "@ai-sdk/mistral": "3.0.51",
     "@ai-sdk/openai": "3.0.84",
     "@ai-sdk/openai-compatible": "2.0.41",
     "@ai-sdk/perplexity": "3.0.26",

packages/opencode/test/session/llm.test.ts

@@ -906,6 +906,117 @@ describe("session.llm.stream", () => {
     },
   )
 
+  const mistralFixture = { providerID: "mistral", modelID: "mistral-small-latest" }
+  it.instance(
+    "replays native Mistral reasoning from chat history",
+    () =>
+      Effect.gen(function* () {
+        const fixture = loadFixture(mistralFixture.providerID, mistralFixture.modelID)
+        const request = waitRequest(
+          "/chat/completions",
+          createEventResponse(
+            [
+              {
+                id: "chatcmpl-mistral",
+                object: "chat.completion.chunk",
+                created: 0,
+                model: fixture.model.id,
+                choices: [{ index: 0, delta: { role: "assistant", content: "Hello" } }],
+              },
+              {
+                id: "chatcmpl-mistral",
+                object: "chat.completion.chunk",
+                created: 0,
+                model: fixture.model.id,
+                choices: [{ index: 0, delta: {}, finish_reason: "stop" }],
+              },
+            ],
+            true,
+          ),
+        )
+
+        const resolved = yield* Provider.use.getModel(
+          ProviderV2.ID.make(mistralFixture.providerID),
+          ModelV2.ID.make(fixture.model.id),
+        )
+        const sessionID = SessionID.make("session-test-mistral-reasoning")
+        const agent = {
+          name: "test",
+          mode: "primary",
+          options: {},
+          permission: [{ permission: "*", pattern: "*", action: "allow" }],
+        } satisfies Agent.Info
+
+        const user = {
+          id: MessageID.make("msg_user-mistral-reasoning"),
+          sessionID,
+          role: "user",
+          time: { created: Date.now() },
+          agent: agent.name,
+          model: { providerID: ProviderV2.ID.make(mistralFixture.providerID), modelID: resolved.id },
+        } satisfies SessionV1.User
+
+        const thinking = {
+          type: "thinking",
+          thinking: [
+            { type: "text", text: "thinking" },
+            {
+              type: "tool_reference",
+              tool: "web_search",
+              title: "Example result",
+              url: "https://example.com/tool",
+              favicon: "https://example.com/favicon.ico",
+              description: "Example description",
+            },
+            { type: "reference", reference_ids: [1, "source-2"] },
+          ],
+          closed: true,
+          signature: "sig-123",
+        }
+
+        yield* drain({
+          user,
+          sessionID,
+          model: resolved,
+          agent,
+          system: ["You are a helpful assistant."],
+          messages: [
+            { role: "user", content: "Hello" },
+            {
+              role: "assistant",
+              content: [
+                {
+                  type: "reasoning",
+                  text: "thinking",
+                  providerOptions: { mistral: { thinking } },
+                },
+                { type: "text", text: "Previous answer" },
+              ],
+            },
+            { role: "user", content: "Continue" },
+          ] satisfies ModelMessage[],
+          tools: {},
+        })
+
+        const capture = yield* Effect.promise(() => request)
+        const messages = capture.body.messages as Array<Record<string, unknown>>
+        expect(messages.find((message) => message.role === "assistant")).toEqual({
+          role: "assistant",
+          content: [thinking, { type: "text", text: "Previous answer" }],
+        })
+      }),
+    {
+      config: () => ({
+        enabled_providers: [mistralFixture.providerID],
+        provider: {
+          [mistralFixture.providerID]: {
+            options: { apiKey: "test-key", baseURL: `${state.server!.url.origin}/v1` },
+          },
+        },
+      }),
+    },
+  )
+
   const alibabaQwenFixture = { providerID: "alibaba", modelID: "qwen-plus" }
   it.instance(
     "service stream cancellation cancels provider response body promptly",