diff --git a/src/agent_manager/api/routes/conversations.py b/src/agent_manager/api/routes/conversations.py
index 1dfbc37f..d202538e 100644
--- a/src/agent_manager/api/routes/conversations.py
+++ b/src/agent_manager/api/routes/conversations.py
@@ -22,6 +22,8 @@
     ConversationSummary,
     CreateConversationRequest,
     CreateConversationResponse,
+    MessageFeedbackRequest,
+    MessageFeedbackResponse,
     MessageOut,
     PaginatedConversationsResponse,
     SendMessageRequest,
@@ -84,6 +86,7 @@ async def list_messages(
             content=message.content,
             status=message.status,
             created_at=message.created_at,
+            feedback=message.feedback,
         )
         for message in messages
     ]
@@ -105,6 +108,28 @@ async def get_usage(
     )
 
 
+@router.post(
+    "/conversations/{conversation_id}/messages/{message_id}/feedback",
+    response_model=MessageFeedbackResponse,
+)
+async def set_message_feedback(
+    conversation_id: str,
+    message_id: str,
+    body: MessageFeedbackRequest,
+    service: Service,
+    caller: Caller,
+) -> MessageFeedbackResponse:
+    with as_http_error():
+        updated = await service.set_message_feedback(
+            conversation_id, message_id, body.feedback, caller
+        )
+    if updated is None:
+        from fastapi import HTTPException
+
+        raise HTTPException(status_code=404, detail="message not found")
+    return MessageFeedbackResponse(message_id=updated.message_id, feedback=updated.feedback)
+
+
 @router.post("/conversations/{conversation_id}/messages", response_model=SendMessageResponse)
 async def send_message(
     conversation_id: str,
diff --git a/src/agent_manager/api/schemas.py b/src/agent_manager/api/schemas.py
index 7cfb2d70..2b620f69 100644
--- a/src/agent_manager/api/schemas.py
+++ b/src/agent_manager/api/schemas.py
@@ -59,6 +59,16 @@ class MessageOut(BaseModel):
     content: str
     status: str
     created_at: datetime
+    feedback: str | None = None
+
+
+class MessageFeedbackRequest(BaseModel):
+    feedback: str = Field(..., pattern="^(thumbs_up|thumbs_down)$")
+
+
+class MessageFeedbackResponse(BaseModel):
+    message_id: str
+    feedback: str | None = None
 
 
 class SendMessageRequest(BaseModel):
diff --git a/src/agent_manager/api/static/widget/api/AgentChatClient.ts b/src/agent_manager/api/static/widget/api/AgentChatClient.ts
index 504d86b8..e3af509b 100644
--- a/src/agent_manager/api/static/widget/api/AgentChatClient.ts
+++ b/src/agent_manager/api/static/widget/api/AgentChatClient.ts
@@ -164,6 +164,21 @@ export class AgentChatClient {
     };
   }
 
+  async setMessageFeedback(
+    conversationId: string,
+    messageId: string,
+    feedback: "thumbs_up" | "thumbs_down",
+  ): Promise<{ message_id: string; feedback: string | null }> {
+    const response = await this.request(
+      `/conversations/${conversationId}/messages/${messageId}/feedback`,
+      {
+        method: "POST",
+        body: JSON.stringify({ feedback }),
+      },
+    );
+    return await response.json();
+  }
+
   async *streamMessage(
     conversationId: string,
     message: string,
diff --git a/src/agent_manager/api/static/widget/react/AgentChatApp.tsx b/src/agent_manager/api/static/widget/react/AgentChatApp.tsx
index 0c528f9f..77c9140d 100644
--- a/src/agent_manager/api/static/widget/react/AgentChatApp.tsx
+++ b/src/agent_manager/api/static/widget/react/AgentChatApp.tsx
@@ -5,6 +5,8 @@ import {
   CopyIcon,
   HistoryIcon,
   SquarePenIcon,
+  ThumbsDownIcon,
+  ThumbsUpIcon,
   XIcon,
 } from "lucide-react";
 import { type Ref, useCallback, useEffect, useMemo, useRef, useState } from "react";
@@ -71,6 +73,7 @@ const toEntries = (message: ChatMessage): MessageEntry[] => {
     runId: message.run_id ?? undefined,
     role: message.role === "user" ? "user" : "ai",
     text: message.content,
+    feedback: message.feedback,
   };
   return message.role === "user" && message.status === "cancelled"
     ? [entry, { id: newId(), role: "ai", text: "", status: "cancelled" }]
@@ -709,6 +712,7 @@ export function AgentChatApp({
                 <ChatMessage
                   key={entry.id}
                   entry={entry}
+                  conversationId={activeId}
                   onApproval={(approval, decision) =>
                     void decideApproval(activeId, entry, approval, decision)
                   }
@@ -716,6 +720,9 @@ export function AgentChatApp({
                     void cancelApproval(activeId, entry.id, approval)
                   }
                   onEdit={() => editMessage(entry)}
+                  onFeedback={(messageId, feedback) =>
+                    void conversation.setMessageFeedback(activeId, messageId, feedback)
+                  }
                   editable={canEdit}
                 />
               ))}
@@ -797,15 +804,19 @@ function Launcher({
 
 function ChatMessage({
   entry,
+  conversationId,
   onApproval,
   onCancelApproval,
   onEdit,
+  onFeedback,
   editable,
 }: {
   entry: MessageEntry;
+  conversationId?: string;
   onApproval: (approval: PendingApproval, decision: ApprovalDecision) => void;
   onCancelApproval: (approval: PendingApproval) => void;
   onEdit: () => void;
+  onFeedback: (messageId: string, feedback: "thumbs_up" | "thumbs_down") => void;
   editable: boolean;
 }) {
   const from = entry.role === "user" ? "user" : "assistant";
@@ -869,7 +880,7 @@ function ChatMessage({
               <MessageResponse>{entry.text}</MessageResponse>
             </MessageContent>
           ) : null}
-          {entry.text.trim() ? <MessageActions text={entry.text} /> : null}
+          {entry.text.trim() ? <MessageActions text={entry.text} feedback={entry.feedback} messageId={entry.messageId} conversationId={conversationId} onFeedback={onFeedback} /> : null}
         </>
       )}
     </Message>
@@ -957,10 +968,60 @@ function ThinkingDots() {
   );
 }
 
-function MessageActions({ text }: { text: string }) {
+function MessageActions({
+  text,
+  feedback,
+  messageId,
+  conversationId,
+  onFeedback,
+}: {
+  text: string;
+  feedback?: "thumbs_up" | "thumbs_down";
+  messageId?: string;
+  conversationId?: string;
+  onFeedback?: (messageId: string, feedback: "thumbs_up" | "thumbs_down") => void;
+}) {
+  const handleThumbsUp = useCallback(() => {
+    if (!messageId || !conversationId || !onFeedback) return;
+    const next = feedback === "thumbs_up" ? null : "thumbs_up";
+    if (next) {
+      void onFeedback(messageId, next);
+    }
+  }, [messageId, conversationId, onFeedback, feedback]);
+
+  const handleThumbsDown = useCallback(() => {
+    if (!messageId || !conversationId || !onFeedback) return;
+    const next = feedback === "thumbs_down" ? null : "thumbs_down";
+    if (next) {
+      void onFeedback(messageId, next);
+    }
+  }, [messageId, conversationId, onFeedback, feedback]);
+
   return (
     <div className="msg-actions">
       <CopyButton text={text} />
+      {messageId && conversationId && onFeedback ? (
+        <div className="feedback-actions">
+          <button
+            aria-label="Thumbs up"
+            aria-pressed={feedback === "thumbs_up"}
+            className={`msg-action feedback-up${feedback === "thumbs_up" ? " active" : ""}`}
+            onClick={handleThumbsUp}
+            type="button"
+          >
+            <ThumbsUpIcon aria-hidden />
+          </button>
+          <button
+            aria-label="Thumbs down"
+            aria-pressed={feedback === "thumbs_down"}
+            className={`msg-action feedback-down${feedback === "thumbs_down" ? " active" : ""}`}
+            onClick={handleThumbsDown}
+            type="button"
+          >
+            <ThumbsDownIcon aria-hidden />
+          </button>
+        </div>
+      ) : null}
     </div>
   );
 }
diff --git a/src/agent_manager/api/static/widget/react/useConversation.ts b/src/agent_manager/api/static/widget/react/useConversation.ts
index 02849442..e3adef7c 100644
--- a/src/agent_manager/api/static/widget/react/useConversation.ts
+++ b/src/agent_manager/api/static/widget/react/useConversation.ts
@@ -56,6 +56,11 @@ export interface Conversation {
   listThreads(limit?: number, cursor?: string | null): Promise<PaginatedThreads>;
   switchTo(conversationId: string): void;
   startNew(): void;
+  setMessageFeedback(
+    conversationId: string,
+    messageId: string,
+    feedback: "thumbs_up" | "thumbs_down",
+  ): Promise<{ message_id: string; feedback: string | null }>;
 }
 
 /** A stored conversation the server will not serve us: gone (404), or owned by
@@ -199,6 +204,12 @@ export function useConversation(
     [endpoint],
   );
 
+  const setMessageFeedback = useCallback(
+    (conversationId: string, messageId: string, feedback: "thumbs_up" | "thumbs_down") =>
+      client.setMessageFeedback(conversationId, messageId, feedback),
+    [client],
+  );
+
   return useMemo(
     () => ({
       peekId,
@@ -213,6 +224,7 @@ export function useConversation(
       listThreads,
       switchTo,
       startNew,
+      setMessageFeedback,
     }),
     [
       peekId,
@@ -227,6 +239,7 @@ export function useConversation(
       listThreads,
       switchTo,
       startNew,
+      setMessageFeedback,
     ],
   );
 }
diff --git a/src/agent_manager/api/static/widget/types.ts b/src/agent_manager/api/static/widget/types.ts
index 13339a69..9e315f0b 100644
--- a/src/agent_manager/api/static/widget/types.ts
+++ b/src/agent_manager/api/static/widget/types.ts
@@ -45,6 +45,7 @@ export interface ChatMessage {
   content: string;
   status: string;
   created_at?: string;
+  feedback?: "thumbs_up" | "thumbs_down";
 }
 
 export type BudgetSeverity = "normal" | "warning" | "critical";
@@ -72,6 +73,7 @@ export interface MessageEntry {
   approvalSubmitting?: boolean;
   approvalCancelling?: boolean;
   approvalError?: string;
+  feedback?: "thumbs_up" | "thumbs_down";
 }
 
 export interface PendingApproval {
diff --git a/src/agent_manager/application/conversation_service.py b/src/agent_manager/application/conversation_service.py
index 6e22a3db..2e1f1334 100644
--- a/src/agent_manager/application/conversation_service.py
+++ b/src/agent_manager/application/conversation_service.py
@@ -167,6 +167,16 @@ async def usage(self, conversation_id: str, principal: Principal) -> TokenBudget
         used = await self._repository.get_token_usage(conversation_id)
         return TokenBudgetUsage.from_totals(used, self._max_tokens)
 
+    async def set_message_feedback(
+        self,
+        conversation_id: str,
+        message_id: str,
+        feedback: str,
+        principal: Principal,
+    ) -> ConversationMessage | None:
+        await self._authorize(conversation_id, principal)
+        return await self._repository.update_message_feedback(message_id, feedback)
+
     async def list_conversations(
         self, principal: Principal, page: PageRequest | None = None
     ) -> Page[ConversationSession]:
diff --git a/src/agent_manager/domain/models.py b/src/agent_manager/domain/models.py
index 831d09c9..6539293d 100644
--- a/src/agent_manager/domain/models.py
+++ b/src/agent_manager/domain/models.py
@@ -108,6 +108,7 @@ class ConversationMessage:
     status: str = "succeeded"
     error_type: str | None = None
     metadata: dict[str, Any] = field(default_factory=dict)
+    feedback: str | None = None
 
 
 @dataclass(frozen=True)
diff --git a/src/agent_manager/domain/repository.py b/src/agent_manager/domain/repository.py
index 02e5816a..0fed34f8 100644
--- a/src/agent_manager/domain/repository.py
+++ b/src/agent_manager/domain/repository.py
@@ -192,3 +192,15 @@ async def add_message(self, conversation_id: str, role: Role, content: str) -> N
     async def list_messages(self, conversation_id: str, limit: int | None = None) -> list[Message]:
         """Messages oldest-first. With `limit`, the most recent `limit`, still
         oldest-first."""
+
+    @abstractmethod
+    async def update_message_feedback(
+        self,
+        message_id: str,
+        feedback: str,
+    ) -> ConversationMessage | None:
+        """Persist a 👍/👎 vote on a single assistant message.
+
+        Returns the updated message, or ``None`` if the message does not exist.
+        """
+        ...
diff --git a/src/agent_manager/infrastructure/persistence/memory_repository.py b/src/agent_manager/infrastructure/persistence/memory_repository.py
index fcf08ad2..ab2c0a81 100644
--- a/src/agent_manager/infrastructure/persistence/memory_repository.py
+++ b/src/agent_manager/infrastructure/persistence/memory_repository.py
@@ -301,6 +301,20 @@ async def list_messages(self, conversation_id: str, limit: int | None = None) ->
         msgs = await self.list_conversation_messages(conversation_id, limit)
         return [Message(role=m.role, content=m.content, created_at=m.created_at) for m in msgs]
 
+    async def update_message_feedback(
+        self,
+        message_id: str,
+        feedback: str,
+    ) -> ConversationMessage | None:
+        for _sid, messages in list(self._messages.items()):
+            for index, message in enumerate(messages):
+                if message.message_id == message_id:
+                    metadata = {**message.metadata, "feedback": feedback}
+                    updated = replace(message, feedback=feedback, metadata=metadata)
+                    messages[index] = updated
+                    return updated
+        return None
+
     async def get_snapshot(self, session_id: str) -> ConversationSnapshot | None:
         return self._snapshots.get(session_id)
 
diff --git a/src/agent_manager/infrastructure/persistence/sql_repository.py b/src/agent_manager/infrastructure/persistence/sql_repository.py
index 30b3560e..e9512504 100644
--- a/src/agent_manager/infrastructure/persistence/sql_repository.py
+++ b/src/agent_manager/infrastructure/persistence/sql_repository.py
@@ -383,6 +383,23 @@ async def list_messages(self, conversation_id: str, limit: int | None = None) ->
             Message(role=row.role, content=row.content, created_at=row.created_at) for row in rows
         ]
 
+    async def update_message_feedback(
+        self,
+        message_id: str,
+        feedback: str,
+    ) -> ConversationMessage | None:
+        async with self._sessions() as session:
+            row = await session.get(ConversationMessageRow, message_id)
+            if row is None:
+                return None
+            metadata = dict(row.metadata_json or {})
+            metadata["feedback"] = feedback
+            row.metadata_json = metadata
+            session.add(row)
+            await session.commit()
+            await session.refresh(row)
+        return _message(row)
+
     async def get_snapshot(self, session_id: str) -> ConversationSnapshot | None:
         async with self._sessions() as session:
             row = await session.get(ConversationSnapshotRow, session_id)
@@ -601,6 +618,9 @@ def _session(row: ConversationSessionRow) -> ConversationSession:
 
 
 def _message_row(message: ConversationMessage) -> ConversationMessageRow:
+    metadata = dict(message.metadata)
+    if message.feedback is not None:
+        metadata["feedback"] = message.feedback
     return ConversationMessageRow(
         message_id=message.message_id,
         session_id=message.session_id,
@@ -621,12 +641,13 @@ def _message_row(message: ConversationMessage) -> ConversationMessageRow:
         latency_ms=message.latency_ms,
         status=message.status,
         error_type=message.error_type,
-        metadata_json=dict(message.metadata),
+        metadata_json=metadata,
         created_at=message.created_at,
     )
 
 
 def _message(row: ConversationMessageRow) -> ConversationMessage:
+    metadata = dict(row.metadata_json or {})
     return ConversationMessage(
         message_id=row.message_id,
         session_id=row.session_id,
@@ -647,7 +668,8 @@ def _message(row: ConversationMessageRow) -> ConversationMessage:
         latency_ms=row.latency_ms,
         status=row.status,
         error_type=row.error_type,
-        metadata=dict(row.metadata_json or {}),
+        metadata=metadata,
+        feedback=metadata.get("feedback"),
         created_at=ensure_utc(row.created_at) or row.created_at,
     )
 
@@ -666,6 +688,7 @@ def _message_json(row: ConversationMessageRow) -> dict[str, Any]:
         "status": row.status,
         "created_at": (ensure_utc(row.created_at) or row.created_at).isoformat(),
         "metadata": dict(row.metadata_json or {}),
+        "feedback": (row.metadata_json or {}).get("feedback"),
     }
 
 
diff --git a/tests/agent_manager/test_api.py b/tests/agent_manager/test_api.py
index 408abb58..fb9025c0 100644
--- a/tests/agent_manager/test_api.py
+++ b/tests/agent_manager/test_api.py
@@ -1434,3 +1434,50 @@ def test_tool_error_text_is_sanitized_in_stream_message() -> None:
     assert response.status_code == 200
     assert "Tool execution failed" in response.text
     assert "localhost" not in response.text
+
+
+def test_set_message_feedback_returns_updated_message(client: TestClient) -> None:
+    cid = client.post("/conversations").json()["conversation_id"]
+    sent = client.post(f"/conversations/{cid}/messages", json={"message": "hello"})
+    assert sent.status_code == 200
+    messages = client.get(f"/conversations/{cid}/messages").json()
+    assistant = next(m for m in messages if m["role"] == "assistant")
+    message_id = assistant["message_id"]
+
+    response = client.post(
+        f"/conversations/{cid}/messages/{message_id}/feedback",
+        json={"feedback": "thumbs_up"},
+    )
+    assert response.status_code == 200
+    body = response.json()
+    assert body["message_id"] == message_id
+    assert body["feedback"] == "thumbs_up"
+
+
+def test_set_message_feedback_returns_404_for_missing_message(client: TestClient) -> None:
+    cid = client.post("/conversations").json()["conversation_id"]
+
+    response = client.post(
+        f"/conversations/{cid}/messages/no-such-id/feedback",
+        json={"feedback": "thumbs_up"},
+    )
+    assert response.status_code == 404
+
+
+def test_another_caller_cannot_set_feedback_on_anothers_conversation(
+    client: TestClient,
+) -> None:
+    u1 = bearer("u1")
+    cid = client.post("/conversations", headers=u1).json()["conversation_id"]
+    client.post(f"/conversations/{cid}/messages", json={"message": "hello"}, headers=u1)
+    messages = client.get(f"/conversations/{cid}/messages", headers=u1).json()
+    assistant = next(m for m in messages if m["role"] == "assistant")
+    message_id = assistant["message_id"]
+
+    u2 = bearer("u2")
+    response = client.post(
+        f"/conversations/{cid}/messages/{message_id}/feedback",
+        json={"feedback": "thumbs_up"},
+        headers=u2,
+    )
+    assert response.status_code == 403
diff --git a/tests/agent_manager/test_service.py b/tests/agent_manager/test_service.py
index 073b6aa4..5d87a6d0 100644
--- a/tests/agent_manager/test_service.py
+++ b/tests/agent_manager/test_service.py
@@ -479,3 +479,37 @@ async def test_adopting_merges_into_conversations_the_account_already_had() -> N
         "signed-in",
         "pre-login",
     }
+
+
+async def test_set_message_feedback_persists_and_returns_message() -> None:
+    service, _ = _service()
+    await service.create(ALICE, session_id="s1")
+    await service.send("s1", "hello", ALICE)
+    history = await service.history("s1", ALICE)
+    assistant_message = next(m for m in history if m.role == Role.ASSISTANT)
+
+    updated = await service.set_message_feedback(
+        "s1", assistant_message.message_id, "thumbs_up", ALICE
+    )
+
+    assert updated is not None
+    assert updated.feedback == "thumbs_up"
+    assert updated.metadata.get("feedback") == "thumbs_up"
+
+
+async def test_set_message_feedback_returns_none_for_missing_message() -> None:
+    service, _ = _service()
+    await service.create(ALICE, session_id="s1")
+
+    updated = await service.set_message_feedback("s1", "no-such-id", "thumbs_up", ALICE)
+
+    assert updated is None
+
+
+async def test_set_message_feedback_is_authorized() -> None:
+    service, _ = _service()
+    await service.create(ALICE, session_id="s1")
+    await service.send("s1", "hello", ALICE)
+
+    with pytest.raises(ConversationAccessDenied):
+        await service.set_message_feedback("s1", "no-such-id", "thumbs_up", BOB)