From 49c60e9065d98a6848e62c717315eb91eeaa6038 Mon Sep 17 00:00:00 2001
From: peetzweg/ <839848+peetzweg@users.noreply.github.com>
Date: Tue, 10 Feb 2026 01:16:40 +0100
Subject: [PATCH] feat(matrix): add thread session isolation (#8241)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
---
 .../matrix/src/matrix/monitor/handler.ts      | 59 ++++++++++++++++++-
 1 file changed, 56 insertions(+), 3 deletions(-)

diff --git a/extensions/matrix/src/matrix/monitor/handler.ts b/extensions/matrix/src/matrix/monitor/handler.ts
index 08f255b5a..eef2bed43 100644
--- a/extensions/matrix/src/matrix/monitor/handler.ts
+++ b/extensions/matrix/src/matrix/monitor/handler.ts
@@ -12,6 +12,7 @@ import {
 } from "openclaw/plugin-sdk";
 import type { CoreConfig, MatrixRoomConfig, ReplyToMode } from "../../types.js";
 import type { MatrixRawEvent, RoomMessageEventContent } from "./types.js";
+import { fetchEventSummary } from "../actions/summary.js";
 import {
   formatPollAsText,
   isPollStartType,
@@ -431,7 +432,7 @@ export function createMatrixRoomMessageHandler(params: MatrixMonitorHandlerParam
         isThreadRoot: false, // @vector-im/matrix-bot-sdk doesn't have this info readily available
       });
 
-      const route = core.channel.routing.resolveAgentRoute({
+      const baseRoute = core.channel.routing.resolveAgentRoute({
         cfg,
         channel: "matrix",
         peer: {
@@ -439,8 +440,57 @@ export function createMatrixRoomMessageHandler(params: MatrixMonitorHandlerParam
           id: isDirectMessage ? senderId : roomId,
         },
       });
+
+      const route = {
+        ...baseRoute,
+        sessionKey: threadRootId
+          ? `${baseRoute.sessionKey}:thread:${threadRootId}`
+          : baseRoute.sessionKey,
+      };
+
+      let threadStarterBody: string | undefined;
+      let threadLabel: string | undefined;
+      let parentSessionKey: string | undefined;
+
+      if (threadRootId) {
+        const existingSession = core.channel.session.readSessionUpdatedAt({
+          storePath: core.channel.session.resolveStorePath(cfg.session?.store, {
+            agentId: baseRoute.agentId,
+          }),
+          sessionKey: route.sessionKey,
+        });
+
+        if (existingSession === undefined) {
+          try {
+            const rootEvent = await fetchEventSummary(client, roomId, threadRootId);
+            if (rootEvent?.body) {
+              const rootSenderName = rootEvent.sender
+                ? await getMemberDisplayName(roomId, rootEvent.sender)
+                : undefined;
+
+              threadStarterBody = core.channel.reply.formatAgentEnvelope({
+                channel: "Matrix",
+                from: rootSenderName ?? rootEvent.sender ?? "Unknown",
+                timestamp: rootEvent.timestamp,
+                envelope: core.channel.reply.resolveEnvelopeFormatOptions(cfg),
+                body: rootEvent.body,
+              });
+
+              threadLabel = `Matrix thread in ${roomName ?? roomId}`;
+              parentSessionKey = baseRoute.sessionKey;
+            }
+          } catch (err) {
+            logVerboseMessage(
+              `matrix: failed to fetch thread root ${threadRootId}: ${String(err)}`,
+            );
+          }
+        }
+      }
+
       const envelopeFrom = isDirectMessage ? senderName : (roomName ?? roomId);
-      const textWithId = `${bodyText}\n[matrix event id: ${messageId} room: ${roomId}]`;
+      const textWithId = threadRootId
+        ? `${bodyText}\n[matrix event id: ${messageId} room: ${roomId} thread: ${threadRootId}]`
+        : `${bodyText}\n[matrix event id: ${messageId} room: ${roomId}]`;
       const storePath = core.channel.session.resolveStorePath(cfg.session?.store, {
         agentId: route.agentId,
       });
@@ -467,7 +517,7 @@ export function createMatrixRoomMessageHandler(params: MatrixMonitorHandlerParam
         To: `room:${roomId}`,
         SessionKey: route.sessionKey,
         AccountId: route.accountId,
-        ChatType: isDirectMessage ? "direct" : "channel",
+        ChatType: threadRootId ? "thread" : isDirectMessage ? "direct" : "channel",
         ConversationLabel: envelopeFrom,
         SenderName: senderName,
         SenderId: senderId,
@@ -490,6 +540,9 @@ export function createMatrixRoomMessageHandler(params: MatrixMonitorHandlerParam
         CommandSource: "text" as const,
         OriginatingChannel: "matrix" as const,
         OriginatingTo: `room:${roomId}`,
+        ThreadStarterBody: threadStarterBody,
+        ThreadLabel: threadLabel,
+        ParentSessionKey: parentSessionKey,
       });
 
       await core.channel.session.recordInboundSession({