Added optional fields param to get work items in batch (#385)

Added new optional `fields` param when getting work items by id in batch

## GitHub issue number #383 

## **Associated Risks**

N/A

## ✅ **PR Checklist**

- [x] **I have read the [contribution
guidelines](https://github.com/microsoft/azure-devops-mcp/blob/main/CONTRIBUTING.md)**
- [x] **I have read the [code of conduct
guidelines](https://github.com/microsoft/azure-devops-mcp/blob/main/CODE_OF_CONDUCT.md)**
- [x] Title of the pull request is clear and informative.
- [x] 👌 Code hygiene
- [x] 🔭 Telemetry added, updated, or N/A
- [x] 📄 Documentation added, updated, or N/A
- [x] 🛡️ Automated tests added, or N/A

## 🧪 **How did you test it?**

Updated manual tests. manual and copilot testing

Author: danhellem

src/tools/workitems.ts

@@ -129,12 +129,17 @@ function configureWorkItemTools(server: McpServer, tokenProvider: () => Promise<
     {
       project: z.string().describe("The name or ID of the Azure DevOps project."),
       ids: z.array(z.number()).describe("The IDs of the work items to retrieve."),
+      fields: z.array(z.string()).optional().describe("Optional list of fields to include in the response. If not provided, a hardcoded default set of fields will be used."),
     },
-    async ({ project, ids }) => {
+    async ({ project, ids, fields }) => {
       const connection = await connectionProvider();
       const workItemApi = await connection.getWorkItemTrackingApi();
-      const fields = ["System.Id", "System.WorkItemType", "System.Title", "System.State", "System.Parent", "System.Tags", "Microsoft.VSTS.Common.StackRank", "System.AssignedTo"];
-      const workitems = await workItemApi.getWorkItemsBatch({ ids, fields }, project);
+      const defaultFields = ["System.Id", "System.WorkItemType", "System.Title", "System.State", "System.Parent", "System.Tags", "Microsoft.VSTS.Common.StackRank", "System.AssignedTo"];
+
+      // If no fields are provided, use the default set of fields
+      const fieldsToUse = !fields || fields.length === 0 ? defaultFields : fields;
+
+      const workitems = await workItemApi.getWorkItemsBatch({ ids, fields: fieldsToUse }, project);
 
       // Format the assignedTo field to include displayName and uniqueName
       // Removing the identity object as the response. It's too much and not needed

test/src/tools/workitems.test.ts

@@ -293,6 +293,74 @@ describe("configureWorkItemTools", () => {
       expect(result.content[0].text).toBe(JSON.stringify([_mockWorkItems], null, 2));
     });
 
+    it("should call workItemApi.getWorkItemsBatch API with custom fields when fields parameter is provided", async () => {
+      configureWorkItemTools(server, tokenProvider, connectionProvider, userAgentProvider);
+
+      const call = (server.tool as jest.Mock).mock.calls.find(([toolName]) => toolName === "wit_get_work_items_batch_by_ids");
+
+      if (!call) throw new Error("wit_get_work_items_batch_by_ids tool not registered");
+      const [, , , handler] = call;
+
+      const mockWorkItemsWithCustomFields = [
+        {
+          id: 297,
+          fields: {
+            "System.Id": 297,
+            "System.Title": "Test Work Item",
+          },
+        },
+      ];
+
+      (mockWorkItemTrackingApi.getWorkItemsBatch as jest.Mock).mockResolvedValue(mockWorkItemsWithCustomFields);
+
+      const params = {
+        ids: [297, 299, 300],
+        project: "Contoso",
+        fields: ["System.Id", "System.Title"],
+      };
+
+      const result = await handler(params);
+
+      expect(mockWorkItemTrackingApi.getWorkItemsBatch).toHaveBeenCalledWith(
+        {
+          ids: params.ids,
+          fields: params.fields,
+        },
+        params.project
+      );
+
+      expect(result.content[0].text).toBe(JSON.stringify(mockWorkItemsWithCustomFields, null, 2));
+    });
+
+    it("should use default fields when an empty fields array is provided", async () => {
+      configureWorkItemTools(server, tokenProvider, connectionProvider, userAgentProvider);
+
+      const call = (server.tool as jest.Mock).mock.calls.find(([toolName]) => toolName === "wit_get_work_items_batch_by_ids");
+
+      if (!call) throw new Error("wit_get_work_items_batch_by_ids tool not registered");
+      const [, , , handler] = call;
+
+      (mockWorkItemTrackingApi.getWorkItemsBatch as jest.Mock).mockResolvedValue([_mockWorkItems]);
+
+      const params = {
+        ids: [297, 299, 300],
+        project: "Contoso",
+        fields: [], // Empty array should trigger default fields
+      };
+
+      const result = await handler(params);
+
+      expect(mockWorkItemTrackingApi.getWorkItemsBatch).toHaveBeenCalledWith(
+        {
+          ids: params.ids,
+          fields: ["System.Id", "System.WorkItemType", "System.Title", "System.State", "System.Parent", "System.Tags", "Microsoft.VSTS.Common.StackRank", "System.AssignedTo"],
+        },
+        params.project
+      );
+
+      expect(result.content[0].text).toBe(JSON.stringify([_mockWorkItems], null, 2));
+    });
+
     it("should transform System.AssignedTo object to formatted string", async () => {
       configureWorkItemTools(server, tokenProvider, connectionProvider, userAgentProvider);