fix(issue-39839): address tool-call extra params parsing for kimi anthropic-messages

src/agents/pi-embedded-runner-extraparams.test.ts

@@ -803,6 +803,40 @@ describe("applyExtraParamsToAgent", () => {
     });
   });
 
+  it("normalizes anthropic tool_choice modes for kimi-coding endpoints", () => {
+    const payloads: Record<string, unknown>[] = [];
+    const baseStreamFn: StreamFn = (_model, _context, options) => {
+      const payload: Record<string, unknown> = {
+        tools: [
+          {
+            name: "read",
+            description: "Read file",
+            input_schema: { type: "object", properties: {} },
+          },
+        ],
+        tool_choice: { type: "auto" },
+      };
+      options?.onPayload?.(payload);
+      payloads.push(payload);
+      return {} as ReturnType<StreamFn>;
+    };
+    const agent = { streamFn: baseStreamFn };
+
+    applyExtraParamsToAgent(agent, undefined, "kimi-coding", "k2p5", undefined, "low");
+
+    const model = {
+      api: "anthropic-messages",
+      provider: "kimi-coding",
+      id: "k2p5",
+      baseUrl: "https://api.kimi.com/coding/",
+    } as Model<"anthropic-messages">;
+    const context: Context = { messages: [] };
+    void agent.streamFn?.(model, context, {});
+
+    expect(payloads).toHaveLength(1);
+    expect(payloads[0]?.tool_choice).toBe("auto");
+  });
+
   it("does not rewrite anthropic tool schema for non-kimi endpoints", () => {
     const payloads: Record<string, unknown>[] = [];
     const baseStreamFn: StreamFn = (_model, _context, options) => {

src/agents/pi-embedded-runner/extra-params.ts

@@ -858,6 +858,15 @@ function normalizeKimiCodingToolChoice(toolChoice: unknown): unknown {
   }
 
   const choice = toolChoice as Record<string, unknown>;
+  if (choice.type === "auto") {
+    return "auto";
+  }
+  if (choice.type === "none") {
+    return "none";
+  }
+  if (choice.type === "required") {
+    return "required";
+  }
   if (choice.type === "any") {
     return "required";
   }