diff --git a/packages/work-sdk/src/azure-devops.ts b/packages/work-sdk/src/azure-devops.ts
index c6efadf..29f02cb 100644
--- a/packages/work-sdk/src/azure-devops.ts
+++ b/packages/work-sdk/src/azure-devops.ts
@@ -199,7 +199,13 @@ function mapWorkItem(
   const typeName = field<string>(item, "System.WorkItemType") ?? "Other";
   const assignedTo = field<AzureIdentity>(item, "System.AssignedTo");
   const priorityValue = Number(field<number | string>(item, "Microsoft.VSTS.Common.Priority"));
-  const teamProject = field<string>(item, "System.TeamProject") ?? project;
+  const teamProject = field<string>(item, "System.TeamProject");
+  if (!teamProject || teamProject.toLowerCase() !== project.toLowerCase()) {
+    throw new WorkAuthorizationError("Azure DevOps work item is outside the configured project", {
+      provider: "azure-devops",
+      details: { configured: project, received: teamProject },
+    });
+  }
   const description = field<string>(item, "System.Description");
   const parent = parentId(item);
   const htmlUrl = item._links?.html?.href ?? `https://dev.azure.com/${encodeURIComponent(organization)}/${encodeURIComponent(project)}/_workitems/edit/${item.id}`;
@@ -468,23 +474,23 @@ export function azureDevOpsWorkAdapter(options: AzureDevOpsWorkAdapterOptions):
 
     async update(id, input, callOptions) {
       throwIfAborted(callOptions?.signal);
-      const needsCurrent = input.parentId !== undefined || input.description === null || input.priority === "none" || input.assigneeIds?.length === 0;
-      const current = needsCurrent ? await getRaw(id, callOptions?.signal) : undefined;
-      const patch: JsonPatchOperation[] = [];
-      if (callOptions?.expectedRevision !== undefined) {
-        const revision = Number(callOptions.expectedRevision);
-        if (!Number.isInteger(revision) || revision < 1) throw new WorkValidationError("expectedRevision must be an Azure DevOps revision number", { provider: "azure-devops", details: { expectedRevision: callOptions.expectedRevision } });
-        patch.push({ op: "test", path: "/rev", value: revision });
-      }
-      patch.push(...patchFor(input, current));
+      const expectedRevision = callOptions?.expectedRevision === undefined ? undefined : Number(callOptions.expectedRevision);
+      if (expectedRevision !== undefined && (!Number.isInteger(expectedRevision) || expectedRevision < 1)) throw new WorkValidationError("expectedRevision must be an Azure DevOps revision number", { provider: "azure-devops", details: { expectedRevision: callOptions?.expectedRevision } });
+      if (input.assigneeIds && input.assigneeIds.length > 1) throw new WorkValidationError("Azure DevOps supports one assignee per work item", { provider: "azure-devops", details: { field: "assigneeIds" } });
+      const current = await getRaw(id, callOptions?.signal);
+      const currentItem = mapWorkItem(current, organization, project, states, kinds);
+      const patch: JsonPatchOperation[] = [{ op: "test", path: "/fields/System.TeamProject", value: field(current, "System.TeamProject") }];
+      if (expectedRevision !== undefined) patch.push({ op: "test", path: "/rev", value: expectedRevision });
+      const changes = patchFor(input, current);
+      patch.push(...changes);
       if (patch.every((operation) => operation.op === "test")) {
-        if (!current) throw new WorkValidationError("Update must contain at least one changed field", { provider: "azure-devops" });
+        const canBeNoOp = input.parentId !== undefined || input.description === null || input.priority === "none" || input.assigneeIds?.length === 0;
+        if (!canBeNoOp) throw new WorkValidationError("Update must contain at least one changed field", { provider: "azure-devops" });
         if (callOptions?.expectedRevision !== undefined && String(current.rev) !== callOptions.expectedRevision) {
           throw new WorkConflictError("Azure DevOps work item changed before the no-op update", { provider: "azure-devops", details: { expected: callOptions.expectedRevision, actual: String(current.rev) } });
         }
-        const item = mapWorkItem(current, organization, project, states, kinds);
-        verifyApplied(item, input);
-        return item;
+        verifyApplied(currentItem, input);
+        return currentItem;
       }
       const raw = await request<AzureWorkItem>(`/_apis/wit/workitems/${encodeURIComponent(id)}?$expand=relations&api-version=7.1`, {
         method: "PATCH",
@@ -500,6 +506,7 @@ export function azureDevOpsWorkAdapter(options: AzureDevOpsWorkAdapterOptions):
     async addComment(id, input: AddCommentInput, callOptions) {
       throwIfAborted(callOptions?.signal);
       if (!input.body.trim()) throw new WorkValidationError("body must not be empty", { provider: "azure-devops" });
+      mapWorkItem(await getRaw(id, callOptions?.signal), organization, project, states, kinds);
       const comment = await request<AzureComment>(`/_apis/wit/workItems/${encodeURIComponent(id)}/comments?format=markdown&api-version=7.1-preview.4`, {
         method: "POST", body: JSON.stringify({ text: input.body }), ...(callOptions?.signal ? { signal: callOptions.signal } : {}),
       });
diff --git a/packages/work-sdk/test/azure-devops.test.ts b/packages/work-sdk/test/azure-devops.test.ts
index 278f93b..16e2592 100644
--- a/packages/work-sdk/test/azure-devops.test.ts
+++ b/packages/work-sdk/test/azure-devops.test.ts
@@ -2,6 +2,7 @@ import { describe, expect, it, vi } from "vitest";
 
 import {
   WorkAuthenticationError,
+  WorkAuthorizationError,
   WorkConflictError,
   WorkRateLimitError,
   WorkUnsupportedError,
@@ -141,6 +142,7 @@ describe("Azure DevOps adapter", () => {
     const updated = await adapter.update("42", { title: "New title", parentId: "11" }, { expectedRevision: "7" });
     expect(updated).toMatchObject({ title: "New title", parentId: "11", revision: "8" });
     expect(calls[1]).toMatchObject({ method: "PATCH", body: [
+      { op: "test", path: "/fields/System.TeamProject", value: "Platform" },
       { op: "test", path: "/rev", value: 7 },
       { op: "add", path: "/fields/System.Title", value: "New title" },
       { op: "remove", path: "/relations/0" },
@@ -165,6 +167,7 @@ describe("Azure DevOps adapter", () => {
 
   it("adds Markdown comments and normalizes authors", async () => {
     const fetcher = vi.fn<WorkFetch>(async (url, init) => {
+      if (!init?.method) return json(item());
       expect(String(url)).toContain("format=markdown&api-version=7.1-preview.4");
       expect(JSON.parse(String(init?.body))).toEqual({ text: "Deployed" });
       return json({ id: 9, text: "Deployed", createdDate: "2026-01-03T00:00:00Z", createdBy: { id: "user-1", displayName: "Ada" } });
@@ -173,6 +176,16 @@ describe("Azure DevOps adapter", () => {
     expect(comment).toMatchObject({ id: "9", body: "Deployed", author: { id: "user-1", displayName: "Ada" } });
   });
 
+  it("rejects cross-project reads and mutations", async () => {
+    const fetcher = vi.fn<WorkFetch>(async () => json(item({ fields: { "System.TeamProject": "Secret" } })));
+    const adapter = azureDevOpsWorkAdapter({ ...baseOptions, fetch: fetcher });
+
+    await expect(adapter.get("42")).rejects.toBeInstanceOf(WorkAuthorizationError);
+    await expect(adapter.update("42", { title: "Cross-project edit" })).rejects.toBeInstanceOf(WorkAuthorizationError);
+    await expect(adapter.addComment("42", { body: "Cross-project comment" })).rejects.toBeInstanceOf(WorkAuthorizationError);
+    expect(fetcher.mock.calls.every(([, init]) => !init?.method)).toBe(true);
+  });
+
   it("fails closed when Azure rules modify a requested field", async () => {
     const fetcher = vi.fn<WorkFetch>(async () => json(item({ fields: { "System.Title": "Rule changed this" } })));
     const adapter = azureDevOpsWorkAdapter({ ...baseOptions, fetch: fetcher });