diff --git a/CHANGELOG.md b/CHANGELOG.md
index efb246185..36cbf339e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@
 
 ### Fixes
 - Auto-reply: prefer `RawBody` for command/directive parsing (WhatsApp + Discord) and prevent fallback runs from clobbering concurrent session updates. (#643) — thanks @mcinteerj.
+- WhatsApp: fix group reactions by preserving message IDs and sender JIDs in history; normalize participant phone numbers to JIDs in outbound reactions. (#640) — thanks @mcinteerj.
 - Cron: `wakeMode: "now"` waits for heartbeat completion (and retries when the main lane is busy). (#666) — thanks @roshanasingh4.
 - Agents/OpenAI: fix Responses tool-only → follow-up turn handling (avoid standalone `reasoning` items that trigger 400 “required following item”).
 - Sandbox: add `clawdbot sandbox explain` (effective policy inspector + fix-it keys); improve “sandbox jail” tool-policy/elevated errors with actionable config key paths; link to docs.
@@ -41,7 +42,6 @@
 - Telegram: serialize media-group processing to avoid missed albums under load.
 - Signal: handle `dataMessage.reaction` events (signal-cli SSE) to avoid broken attachment errors. (#637) — thanks @neist.
 - Docs: showcase entries for ParentPay, R2 Upload, iOS TestFlight, and Oura Health. (#650) — thanks @henrino3.
-
 ## 2026.1.9
 
 ### Highlights
diff --git a/src/web/auto-reply.ts b/src/web/auto-reply.ts
index 902db7792..5da3376c1 100644
--- a/src/web/auto-reply.ts
+++ b/src/web/auto-reply.ts
@@ -826,7 +826,13 @@ export async function monitorWebProvider(
     DEFAULT_GROUP_HISTORY_LIMIT;
   const groupHistories = new Map<
     string,
-    Array<{ sender: string; body: string; timestamp?: number }>
+    Array<{
+      sender: string;
+      body: string;
+      timestamp?: number;
+      id?: string;
+      senderJid?: string;
+    }>
   >();
   const groupMemberNames = new Map<string, Map<string, string>>();
   const sleep =
@@ -1104,6 +1110,8 @@ export async function monitorWebProvider(
           sender: string;
           body: string;
           timestamp?: number;
+          id?: string;
+          senderJid?: string;
         }>;
         suppressGroupHistoryClear?: boolean;
       },
@@ -1123,14 +1131,17 @@ export async function monitorWebProvider(
         if (historyWithoutCurrent.length > 0) {
           const lineBreak = "\\n";
           const historyText = historyWithoutCurrent
-            .map((m) =>
-              formatAgentEnvelope({
+            .map((m) => {
+              const bodyWithId = m.id
+                ? `${m.body}\n[message_id: ${m.id}]`
+                : m.body;
+              return formatAgentEnvelope({
                 provider: "WhatsApp",
                 from: conversationId,
                 timestamp: m.timestamp,
-                body: `${m.sender}: ${m.body}`,
-              }),
-            )
+                body: `${m.sender}: ${bodyWithId}`,
+              });
+            })
             .join(lineBreak);
           combinedBody = buildHistoryContext({
             historyText,
@@ -1554,11 +1565,19 @@ export async function monitorWebProvider(
                 sender: string;
                 body: string;
                 timestamp?: number;
+                id?: string;
+                senderJid?: string;
               }>);
+            const sender =
+              msg.senderName && msg.senderE164
+                ? `${msg.senderName} (${msg.senderE164})`
+                : (msg.senderName ?? msg.senderE164 ?? "Unknown");
             history.push({
-              sender: msg.senderName ?? msg.senderE164 ?? "Unknown",
+              sender,
               body: msg.body,
               timestamp: msg.timestamp,
+              id: msg.id,
+              senderJid: msg.senderJid,
             });
             while (history.length > groupHistoryLimit) history.shift();
             groupHistories.set(groupHistoryKey, history);
diff --git a/src/web/inbound.ts b/src/web/inbound.ts
index aeae8f919..87ea51d88 100644
--- a/src/web/inbound.ts
+++ b/src/web/inbound.ts
@@ -620,7 +620,7 @@ export async function monitorWebInbox(options: {
             remoteJid: jid,
             id: messageId,
             fromMe,
-            participant,
+            participant: participant ? toWhatsappJid(participant) : undefined,
           },
         },
       });
diff --git a/src/web/monitor-inbox.test.ts b/src/web/monitor-inbox.test.ts
index 285de40ab..6463d5797 100644
--- a/src/web/monitor-inbox.test.ts
+++ b/src/web/monitor-inbox.test.ts
@@ -1402,4 +1402,36 @@ describe("web monitor inbox", () => {
 
     await listener.close();
   });
+
+  it("normalizes participant phone numbers to JIDs in sendReaction", async () => {
+    const listener = await monitorWebInbox({
+      verbose: false,
+      onMessage: vi.fn(),
+      accountId: ACCOUNT_ID,
+      authDir,
+    });
+    const sock = await createWaSocket();
+
+    await listener.sendReaction(
+      "12345@g.us",
+      "msg123",
+      "👍",
+      false,
+      "+6421000000",
+    );
+
+    expect(sock.sendMessage).toHaveBeenCalledWith("12345@g.us", {
+      react: {
+        text: "👍",
+        key: {
+          remoteJid: "12345@g.us",
+          id: "msg123",
+          fromMe: false,
+          participant: "6421000000@s.whatsapp.net",
+        },
+      },
+    });
+
+    await listener.close();
+  });
 });