fix(ui): default human task replies to latest assigning agent

doc/PRODUCT.md

@@ -67,6 +67,11 @@ Tasks have parentage. Every task exists in service of a parent task, all the way
 
 The current issue model includes stable issue identifiers, parent/sub-issues, blockers, a single assignee, comments, issue documents, attachments and work products, and review/approval handoffs. That structure keeps work inspectable by both the board and agents while still allowing agents to decompose work into smaller tasks.
 
+When a task is assigned to the current human, the message composer defaults to
+the latest agent that assigned it to them. If no assignment is available, it uses
+the latest other commenter, or leaves the recipient empty. A manual recipient
+choice stays selected while task data refreshes.
+
 ### Company Skills and Policy
 
 Company skills are shared operating capabilities, not privileged objects by default. Every authenticated agent in a company can create, import, install, edit, update, test, reset, and remove that company's skills unless the company has configured an explicit restriction.

ui/src/components/CommentThread.test.tsx

@@ -44,7 +44,14 @@ vi.mock("./MarkdownEditor", () => ({
 }));
 
 vi.mock("./InlineEntitySelector", () => ({
-  InlineEntitySelector: () => null,
+  InlineEntitySelector: ({ value, onChange }: { value: string; onChange: (value: string) => void }) => (
+    <select aria-label="Test recipient" value={value} onChange={(event) => onChange(event.target.value)}>
+      <option value="agent:first">First agent</option>
+      <option value="agent:latest">Latest agent</option>
+      <option value="user:me">Me</option>
+      <option value="">No responsible</option>
+    </select>
+  ),
 }));
 
 vi.mock("./ApprovalCard", () => ({
@@ -78,6 +85,34 @@ describe("CommentThread", () => {
   let writeTextMock: ReturnType<typeof vi.fn<(text: string) => Promise<void>>>;
   let execCommandMock: ReturnType<typeof vi.fn<typeof document.execCommand>>;
 
+  it("updates automatic suggestions but preserves manual choices until the task changes", () => {
+    const root = createRoot(container);
+    const render = (suggestion: string, draftKey = "task-one") => act(() => root.render(
+      <MemoryRouter>
+        <CommentThread comments={[]} onAdd={async () => {}} enableReassign
+          reassignOptions={[{ id: "agent:first", label: "First agent" }]}
+          currentAssigneeValue="user:me" suggestedAssigneeValue={suggestion} draftKey={draftKey} />
+      </MemoryRouter>,
+    ));
+    const selector = () => container.querySelector('select[aria-label="Test recipient"]') as HTMLSelectElement;
+    render("agent:first");
+    expect(selector().value).toBe("agent:first");
+    render("agent:latest");
+    expect(selector().value).toBe("agent:latest");
+    for (const manual of ["user:me", ""]) {
+      act(() => {
+        selector().value = manual;
+        selector().dispatchEvent(new Event("change", { bubbles: true }));
+      });
+      render("agent:first");
+      render("agent:latest");
+      expect(selector().value).toBe(manual);
+    }
+    render("agent:first", "task-two");
+    expect(selector().value).toBe("agent:first");
+    act(() => root.unmount());
+  });
+
   beforeEach(() => {
     container = document.createElement("div");
     document.body.appendChild(container);

ui/src/components/CommentThread.tsx

@@ -752,6 +752,12 @@ export function CommentThread({
   const [submitting, setSubmitting] = useState(false);
   const [attaching, setAttaching] = useState(false);
   const effectiveSuggestedAssigneeValue = suggestedAssigneeValue ?? currentAssigneeValue;
+  const manualAssigneeRef = useRef(false);
+  const assigneeDraftKeyRef = useRef(draftKey);
+  const selectAssignee = (value: string) => {
+    manualAssigneeRef.current = true;
+    setReassignTarget(value);
+  };
   const [reassignTarget, setReassignTarget] = useState(effectiveSuggestedAssigneeValue);
   const [highlightCommentId, setHighlightCommentId] = useState<string | null>(null);
   const [votingTargetId, setVotingTargetId] = useState<string | null>(null);
@@ -852,8 +858,12 @@ export function CommentThread({
   }, []);
 
   useEffect(() => {
-    setReassignTarget(effectiveSuggestedAssigneeValue);
-  }, [effectiveSuggestedAssigneeValue]);
+    if (assigneeDraftKeyRef.current !== draftKey) {
+      assigneeDraftKeyRef.current = draftKey;
+      manualAssigneeRef.current = false;
+    }
+    if (!manualAssigneeRef.current) setReassignTarget(effectiveSuggestedAssigneeValue);
+  }, [draftKey, effectiveSuggestedAssigneeValue]);
 
   // Scroll to comment when URL hash matches #comment-{id}
   useEffect(() => {
@@ -898,6 +908,7 @@ export function CommentThread({
     try {
       await onAdd(submittedBody, reopen, reassignment ?? undefined);
       if (draftKey) clearDraft(draftKey);
+      manualAssigneeRef.current = false;
       setReassignTarget(effectiveSuggestedAssigneeValue);
     } catch {
       setBody((current) =>
@@ -1051,7 +1062,7 @@ export function CommentThread({
                 noneLabel="No responsible"
                 searchPlaceholder="Search responsible..."
                 emptyMessage="No responsible found."
-                onChange={setReassignTarget}
+                onChange={selectAssignee}
                 className="text-xs h-8"
                 renderTriggerValue={(option) => {
                   if (!option) return <span className="text-muted-foreground">Responsible</span>;

ui/src/components/IssueChatThread.test.tsx

@@ -167,7 +167,14 @@ vi.mock("./MarkdownEditor", () => ({
 }));
 
 vi.mock("./InlineEntitySelector", () => ({
-  InlineEntitySelector: () => null,
+  InlineEntitySelector: ({ value, onChange }: { value: string; onChange: (value: string) => void }) => (
+    <select aria-label="Test recipient" value={value} onChange={(event) => onChange(event.target.value)}>
+      <option value="agent:first">First agent</option>
+      <option value="agent:latest">Latest agent</option>
+      <option value="user:me">Me</option>
+      <option value="">No responsible</option>
+    </select>
+  ),
 }));
 
 vi.mock("./Identity", () => ({
@@ -375,6 +382,34 @@ function createFileDragEvent(type: string, files: File[]) {
 describe("IssueChatThread", () => {
   let container: HTMLDivElement;
 
+  it("updates automatic suggestions but preserves manual choices until the task changes", () => {
+    const root = createRoot(container);
+    const render = (suggestion: string, draftKey = "task-one") => act(() => root.render(
+      <MemoryRouter>
+        <IssueChatThread comments={[]} onAdd={async () => {}} enableReassign
+          reassignOptions={[{ id: "agent:first", label: "First agent" }]}
+          currentAssigneeValue="user:me" suggestedAssigneeValue={suggestion} draftKey={draftKey} />
+      </MemoryRouter>,
+    ));
+    const selector = () => container.querySelector('select[aria-label="Test recipient"]') as HTMLSelectElement;
+    render("agent:first");
+    expect(selector().value).toBe("agent:first");
+    render("agent:latest");
+    expect(selector().value).toBe("agent:latest");
+    for (const manual of ["user:me", ""]) {
+      act(() => {
+        selector().value = manual;
+        selector().dispatchEvent(new Event("change", { bubbles: true }));
+      });
+      render("agent:first");
+      render("agent:latest");
+      expect(selector().value).toBe(manual);
+    }
+    render("agent:first", "task-two");
+    expect(selector().value).toBe("agent:first");
+    act(() => root.unmount());
+  });
+
   beforeEach(() => {
     container = document.createElement("div");
     document.body.appendChild(container);

ui/src/components/IssueChatThread.tsx

@@ -4779,6 +4779,12 @@ const IssueChatComposer = forwardRef<
   const dragDepthRef = useRef(0);
   const effectiveSuggestedAssigneeValue =
     suggestedAssigneeValue ?? currentAssigneeValue;
+  const manualAssigneeRef = useRef(false);
+  const assigneeDraftKeyRef = useRef(draftKey);
+  const selectAssignee = (value: string) => {
+    manualAssigneeRef.current = true;
+    setReassignTarget(value);
+  };
   const [reassignTarget, setReassignTarget] = useState(
     effectiveSuggestedAssigneeValue,
   );
@@ -4935,8 +4941,12 @@ const IssueChatComposer = forwardRef<
   }, [draftKey]);
 
   useEffect(() => {
-    setReassignTarget(effectiveSuggestedAssigneeValue);
-  }, [effectiveSuggestedAssigneeValue]);
+    if (assigneeDraftKeyRef.current !== draftKey) {
+      assigneeDraftKeyRef.current = draftKey;
+      manualAssigneeRef.current = false;
+    }
+    if (!manualAssigneeRef.current) setReassignTarget(effectiveSuggestedAssigneeValue);
+  }, [draftKey, effectiveSuggestedAssigneeValue]);
 
   useEffect(() => {
     setPendingWorkMode(resolvedIssueWorkMode);
@@ -5081,6 +5091,7 @@ const IssueChatComposer = forwardRef<
       setComposerAttachments((current) =>
         current.filter((item) => !submittedAttachmentKeys.has(item.id)),
       );
+      manualAssigneeRef.current = false;
       setReassignTarget(effectiveSuggestedAssigneeValue);
       setRunSettings(null);
     } catch (error) {
@@ -5622,7 +5633,7 @@ const IssueChatComposer = forwardRef<
             overrides={assigneeAdapterOverrides}
             settings={runSettings}
             onSettingsChange={setRunSettings}
-            onAssigneeChange={setReassignTarget}
+            onAssigneeChange={selectAssignee}
             triggerRef={reassignTriggerRef}
             renderAssigneeIdentity={(value) => {
               const selected = value.startsWith("agent:") ? agentMap.get(value.slice(6)) : null;
@@ -5638,7 +5649,7 @@ const IssueChatComposer = forwardRef<
             noneLabel="No responsible"
             searchPlaceholder="Search responsible..."
             emptyMessage="No responsible found."
-            onChange={setReassignTarget}
+            onChange={selectAssignee}
             className="h-8 text-xs"
             renderTriggerValue={(option) => {
               if (!option)

ui/src/components/TaskChatThread.tsx

@@ -524,6 +524,7 @@ export function TaskChatThread(props: TaskChatThreadProps) {
     conversationMode,
     reassignOptions,
     currentAssigneeValue,
+    suggestedAssigneeValue,
     assigneeAdapterOverrides,
     issueStatus,
     issueAssigneeAgentId = null,
@@ -601,12 +602,15 @@ export function TaskChatThread(props: TaskChatThreadProps) {
   const [pendingComposerAssignee, setPendingComposerAssignee] = useState<
     string | null
   >(null);
-  const effectiveGoalAgentId =
-    pendingComposerAssignee === null
-      ? issueAssigneeAgentId
-      : pendingComposerAssignee.startsWith("agent:")
-        ? pendingComposerAssignee.slice("agent:".length) || null
-        : null;
+  const composerSuggestedAssignee = currentUserId && currentAssigneeValue === `user:${currentUserId}`
+    ? suggestedAssigneeValue
+    : undefined;
+  const effectiveComposerAssignee = pendingComposerAssignee ?? composerSuggestedAssignee;
+  const effectiveGoalAgentId = effectiveComposerAssignee === undefined
+    ? issueAssigneeAgentId
+    : effectiveComposerAssignee.startsWith("agent:")
+      ? effectiveComposerAssignee.slice("agent:".length) || null
+      : null;
   const runnerGoal = useRunnerGoalControl(issueId, effectiveGoalAgentId);
 
   useEffect(() => {
@@ -3203,6 +3207,7 @@ export function TaskChatThread(props: TaskChatThreadProps) {
                       modelAgents={agentMap}
                       userProfileMap={userProfileMap}
                       currentAssigneeValue={currentAssigneeValue}
+                      suggestedAssigneeValue={composerSuggestedAssignee}
                       companyId={companyId}
                       assigneeAdapterOverrides={assigneeAdapterOverrides}
                       onPendingAssigneeChange={setPendingComposerAssignee}

ui/src/components/task-chat/TaskChatComposer.test.tsx

@@ -1701,6 +1701,25 @@ describe("TaskChatComposer", () => {
     ).toBe("agent:a2");
   });
 
+  it("uses assignment suggestions and retains a manual human choice after refresh", async () => {
+    const view = (suggestion: string) => <TaskChatComposer onAdd={vi.fn()} workMode="standard"
+      enableReassign currentAssigneeValue="user:u1" suggestedAssigneeValue={suggestion}
+      reassignOptions={[{ id: "agent:a1", label: "Alpha" }, { id: "agent:a2", label: "Beta" }, { id: "user:u1", label: "Me" }]}
+      agentMap={new Map([["a1", { icon: "bot" }], ["a2", { icon: "bot" }]])} />;
+    render(view("agent:a1"));
+    const trigger = () => container.querySelector<HTMLButtonElement>('[data-testid="task-chat-composer-assignee"]')!;
+    expect(trigger().textContent).toContain("Alpha");
+    flushSync(() => root!.render(view("agent:a2")));
+    expect(trigger().textContent).toContain("Beta");
+    flushSync(() => trigger().click());
+    await flushAsync();
+    const me = document.querySelector('[data-assignee-identity="user:u1"]')!.closest("button")!;
+    flushSync(() => me.click());
+    await flushAsync();
+    flushSync(() => root!.render(view("agent:a1")));
+    expect(trigger().textContent).toContain("Me");
+  });
+
   it("shows human avatars in assignee options and after selection", async () => {
     render(
       <TaskChatComposer

ui/src/components/task-chat/TaskChatComposer.tsx

@@ -142,6 +142,7 @@ interface TaskChatComposerProps {
     { label: string; image: string | null }
   > | null;
   currentAssigneeValue?: string;
+  suggestedAssigneeValue?: string;
   onPendingAssigneeChange?: (value: string | null) => void;
   issueStatus?: string;
   /** Mobile document-flow host: 16px editor text so iOS doesn't zoom on focus. */
@@ -397,6 +398,7 @@ export function TaskChatComposer({
   assigneeAdapterOverrides,
   userProfileMap,
   currentAssigneeValue = "",
+  suggestedAssigneeValue,
   onPendingAssigneeChange,
   issueStatus,
   mobile = false,
@@ -638,7 +640,7 @@ export function TaskChatComposer({
   const showAssignee = Boolean(
     enableReassign && reassignOptions && reassignOptions.length > 0,
   );
-  const assigneeValue = creation ? currentAssigneeValue : pendingAssignee ?? currentAssigneeValue;
+  const assigneeValue = creation ? currentAssigneeValue : pendingAssignee ?? suggestedAssigneeValue ?? currentAssigneeValue;
   const assigneeLabel =
     reassignOptions?.find((o) => o.id === assigneeValue)?.label ?? "Unassigned";
   const assigneeName =

ui/src/lib/assignees.test.ts

@@ -1,3 +1,4 @@
+import type { ActivityEvent } from "@paperclipai/shared";
 import { describe, expect, it } from "vitest";
 import {
   assigneeValueFromSelection,
@@ -72,14 +73,14 @@ describe("assignee selection helpers", () => {
     ).toBe("agent:agent-123");
   });
 
-  it("falls back to the actual assignee when there is no better commenter hint", () => {
+  it("leaves the recipient empty instead of defaulting to the current human", () => {
     expect(
       suggestedCommentAssigneeValue(
         { assigneeUserId: "board-user" },
         [{ authorUserId: "board-user" }],
         "board-user",
       ),
-    ).toBe("user:board-user");
+    ).toBe("");
   });
 
   it("skips the current agent when choosing a suggested commenter assignee", () => {
@@ -97,3 +98,45 @@ describe("assignee selection helpers", () => {
     ).toBe("agent:agent-123");
   });
 });
+
+
+describe("assignment history suggestions", () => {
+  const assignment = (actorId: string, date: string, details: Record<string, unknown> = {}): ActivityEvent => ({
+    companyId: "company", entityType: "issue", entityId: "task", agentId: actorId, runId: null,
+    id: actorId, actorType: "agent", actorId, action: "issue.updated",
+    createdAt: new Date(date), details: { assigneeUserId: "me", _previous: { assigneeUserId: null }, ...details },
+  });
+  const suggest = (activity: ActivityEvent[]) => suggestedCommentAssigneeValue(
+    { assigneeUserId: "me" }, [{ authorAgentId: "commenter" }], "me", undefined, activity,
+  );
+
+  it("uses the latest assigning actor in either history order, ahead of commenters", () => {
+    const older = assignment("first", "2026-01-01");
+    const newer = assignment("last", "2026-02-01");
+    expect(suggest([older, newer])).toBe("agent:last");
+    expect(suggest([newer, older])).toBe("agent:last");
+  });
+
+  it("ignores other recipients, human actors, non-assignment events and unchanged fields", () => {
+    const valid = assignment("assigner", "2026-01-01");
+    const invalid = assignment("other", "2026-02-01");
+    expect(suggest([
+      valid,
+      { ...invalid, actorType: "user" },
+      { ...invalid, action: "issue.comment_added" },
+      assignment("other-user", "2026-02-01", { assigneeUserId: "someone-else" }),
+      assignment("no-op", "2026-02-01", { _previous: { assigneeUserId: "me" } }),
+      assignment("resent", "2026-02-01", { _previous: { status: "todo" } }),
+    ])).toBe("agent:assigner");
+  });
+
+  it("includes the agent that created a task assigned to the human", () => {
+    expect(suggest([{ ...assignment("creator", "2026-01-01"), action: "issue.created" }])).toBe("agent:creator");
+  });
+
+  it("keeps the existing commenter fallback and other task defaults", () => {
+    expect(suggest([])).toBe("agent:commenter");
+    expect(suggestedCommentAssigneeValue({ assigneeAgentId: "owner" }, [], "me")).toBe("agent:owner");
+    expect(suggestedCommentAssigneeValue({ assigneeUserId: "someone-else" }, [], "me")).toBe("user:someone-else");
+  });
+});

ui/src/lib/assignees.ts

@@ -1,3 +1,5 @@
+import type { ActivityEvent } from "@paperclipai/shared";
+
 export interface AssigneeSelection {
   assigneeAgentId: string | null;
   assigneeUserId: string | null;
@@ -30,7 +32,27 @@ export function suggestedCommentAssigneeValue(
   comments: CommentAssigneeSuggestionComment[] | null | undefined,
   currentUserId: string | null | undefined,
   currentAgentId?: string | null | undefined,
+  activity: readonly ActivityEvent[] = [],
 ): string {
+  const assignedToCurrentUser = Boolean(currentUserId && issue.assigneeUserId === currentUserId);
+  if (assignedToCurrentUser) {
+    const assignment = activity
+      .filter((event) => {
+        if (event.actorType !== "agent" || !event.actorId || event.actorId === currentAgentId) return false;
+        const details = event.details;
+        if (!details || details.assigneeUserId !== currentUserId) return false;
+        if (event.action === "issue.created") return true;
+        if (event.action !== "issue.updated") return false;
+        const previous = details._previous;
+        // Updates can resend unchanged fields. Only a real assignment counts.
+        return previous !== null && typeof previous === "object"
+          && Object.hasOwn(previous, "assigneeUserId")
+          && (previous as Record<string, unknown>).assigneeUserId !== currentUserId;
+      })
+      .sort((a, b) => new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime())[0];
+    if (assignment) return `agent:${assignment.actorId}`;
+  }
+
   if (comments && comments.length > 0 && (currentUserId || currentAgentId)) {
     for (let i = comments.length - 1; i >= 0; i--) {
       const comment = comments[i];
@@ -43,7 +65,7 @@ export function suggestedCommentAssigneeValue(
     }
   }
 
-  return assigneeValueFromSelection(issue);
+  return assignedToCurrentUser ? "" : assigneeValueFromSelection(issue);
 }
 
 export function parseAssigneeValue(value: string): AssigneeSelection {

ui/src/pages/IssueDetail.tsx

@@ -3841,14 +3841,22 @@ export function TaskDetailSurface({ conversation, tasksTab }: { tasksTab?: TaskS
     [issue],
   );
 
+  const { data: assignmentActivity } = useQuery({
+    queryKey: queryKeys.issues.activity(issueId!),
+    queryFn: () => activityApi.forIssue(issueId!),
+    enabled: Boolean(issueId && currentUserId && issue?.assigneeUserId === currentUserId),
+  });
+
   const suggestedAssigneeValue = useMemo(
     () =>
       suggestedCommentAssigneeValue(
         issue ?? {},
         mergeIssueComments(comments ?? [], optimisticComments),
         currentUserId,
+        undefined,
+        assignmentActivity,
       ),
-    [issue, comments, optimisticComments, currentUserId],
+    [issue, comments, optimisticComments, currentUserId, assignmentActivity],
   );
 
   const threadComments = useMemo(

ui/src/pages/Pipelines.tsx

@@ -2177,8 +2177,10 @@ export function PipelineItemDetailView({ pipelineId, caseId }: { pipelineId: str
         starterAssigneeValue ? parseAssigneeValue(starterAssigneeValue) : activeConversationIssue ?? {},
         conversationComments,
         currentUserId,
+        undefined,
+        conversationActivity,
       ),
-    [activeConversationIssue, conversationComments, currentUserId, starterAssigneeValue],
+    [activeConversationIssue, conversationComments, currentUserId, starterAssigneeValue, conversationActivity],
   );
   const conversationRunningRun = useMemo(
     () => resolveRunningPipelineConversationRun(resolvedConversationActiveRun, resolvedConversationLiveRuns),