fix: enforce Mistral tool call ids (#1372) (thanks @zerone0x)

src/agents/tool-call-id.test.ts

@@ -30,9 +30,7 @@ describe("sanitizeToolCallIdsForCloudCodeAssist", () => {
       const input = [
         {
           role: "assistant",
-          content: [
-            { type: "toolCall", id: "call|item:123", name: "read", arguments: {} },
-          ],
+          content: [{ type: "toolCall", id: "call|item:123", name: "read", arguments: {} }],
         },
         {
           role: "toolResult",
@@ -141,13 +139,18 @@ describe("sanitizeToolCallIdsForCloudCodeAssist", () => {
     });
   });
 
-  describe("strict mode (for Mistral/OpenRouter)", () => {
+  describe("strict mode (alphanumeric only)", () => {
     it("strips underscores and hyphens from tool call IDs", () => {
       const input = [
         {
           role: "assistant",
           content: [
-            { type: "toolCall", id: "whatsapp_login_1768799841527_1", name: "login", arguments: {} },
+            {
+              type: "toolCall",
+              id: "whatsapp_login_1768799841527_1",
+              name: "login",
+              arguments: {},
+            },
           ],
         },
         {
@@ -216,4 +219,50 @@ describe("sanitizeToolCallIdsForCloudCodeAssist", () => {
       expect(r2.toolCallId).toBe(b.id);
     });
   });
+
+  describe("strict9 mode (Mistral tool call IDs)", () => {
+    it("enforces alphanumeric IDs with length 9", () => {
+      const input = [
+        {
+          role: "assistant",
+          content: [
+            { type: "toolCall", id: "call_abc|item:123", name: "read", arguments: {} },
+            { type: "toolCall", id: "call_abc|item:456", name: "read", arguments: {} },
+          ],
+        },
+        {
+          role: "toolResult",
+          toolCallId: "call_abc|item:123",
+          toolName: "read",
+          content: [{ type: "text", text: "one" }],
+        },
+        {
+          role: "toolResult",
+          toolCallId: "call_abc|item:456",
+          toolName: "read",
+          content: [{ type: "text", text: "two" }],
+        },
+      ] satisfies AgentMessage[];
+
+      const out = sanitizeToolCallIdsForCloudCodeAssist(input, "strict9");
+      expect(out).not.toBe(input);
+
+      const assistant = out[0] as Extract<AgentMessage, { role: "assistant" }>;
+      const a = assistant.content?.[0] as { id?: string };
+      const b = assistant.content?.[1] as { id?: string };
+
+      expect(typeof a.id).toBe("string");
+      expect(typeof b.id).toBe("string");
+      expect(a.id).not.toBe(b.id);
+      expect(a.id?.length).toBe(9);
+      expect(b.id?.length).toBe(9);
+      expect(isValidCloudCodeAssistToolId(a.id as string, "strict9")).toBe(true);
+      expect(isValidCloudCodeAssistToolId(b.id as string, "strict9")).toBe(true);
+
+      const r1 = out[1] as Extract<AgentMessage, { role: "toolResult" }>;
+      const r2 = out[2] as Extract<AgentMessage, { role: "toolResult" }>;
+      expect(r1.toolCallId).toBe(a.id);
+      expect(r2.toolCallId).toBe(b.id);
+    });
+  });
 });