diff --git a/src/agents/tools/sessions-send-helpers.test.ts b/src/agents/tools/sessions-send-helpers.test.ts
index b08c6d89e71..b66ce99b42d 100644
--- a/src/agents/tools/sessions-send-helpers.test.ts
+++ b/src/agents/tools/sessions-send-helpers.test.ts
@@ -51,6 +51,28 @@ describe("resolveAnnounceTargetFromKey", () => {
             },
           },
         },
+        {
+          pluginId: "matrix",
+          source: "test",
+          plugin: {
+            id: "matrix",
+            meta: {
+              id: "matrix",
+              label: "Matrix",
+              selectionLabel: "Matrix",
+              docsPath: "/channels/matrix",
+              blurb: "Matrix test stub.",
+            },
+            capabilities: { chatTypes: ["direct", "channel", "thread"] },
+            messaging: {
+              resolveSessionTarget: ({ id }: { id: string }) => `channel:${id}`,
+            },
+            config: {
+              listAccountIds: () => ["default"],
+              resolveAccount: () => ({}),
+            },
+          },
+        },
         {
           pluginId: "telegram",
           source: "test",
@@ -107,4 +129,16 @@ describe("resolveAnnounceTargetFromKey", () => {
       threadId: "1699999999.0001",
     });
   });
+
+  it("preserves colon-delimited matrix ids for channel and thread targets", () => {
+    expect(
+      resolveAnnounceTargetFromKey(
+        "agent:main:matrix:channel:!room:example.org:thread:$AbC123:example.org",
+      ),
+    ).toEqual({
+      channel: "matrix",
+      to: "channel:!room:example.org",
+      threadId: "$AbC123:example.org",
+    });
+  });
 });
diff --git a/src/agents/tools/sessions-send-helpers.ts b/src/agents/tools/sessions-send-helpers.ts
index cb104204e3c..db2d24293aa 100644
--- a/src/agents/tools/sessions-send-helpers.ts
+++ b/src/agents/tools/sessions-send-helpers.ts
@@ -4,6 +4,7 @@ import {
 } from "../../channels/plugins/index.js";
 import { normalizeChannelId as normalizeChatChannelId } from "../../channels/registry.js";
 import type { OpenClawConfig } from "../../config/config.js";
+import { parseSessionThreadInfo } from "../../config/sessions/delivery-info.js";
 
 const ANNOUNCE_SKIP_TOKEN = "ANNOUNCE_SKIP";
 const REPLY_SKIP_TOKEN = "REPLY_SKIP";
@@ -28,20 +29,9 @@ export function resolveAnnounceTargetFromKey(sessionKey: string): AnnounceTarget
     return null;
   }
 
-  // Extract topic/thread ID from rest (supports both :topic: and :thread:)
-  // Telegram uses :topic:, other platforms use :thread:
-  let threadId: string | undefined;
   const restJoined = rest.join(":");
-  const topicMatch = restJoined.match(/:topic:([^:]+)$/);
-  const threadMatch = restJoined.match(/:thread:([^:]+)$/);
-  const match = topicMatch || threadMatch;
-
-  if (match) {
-    threadId = match[1]; // Keep as string to match AgentCommandOpts.threadId
-  }
-
-  // Remove :topic:N or :thread:N suffix from ID for target
-  const id = match ? restJoined.replace(/:(topic|thread):[^:]+$/, "") : restJoined.trim();
+  const { baseSessionKey, threadId } = parseSessionThreadInfo(restJoined);
+  const id = (baseSessionKey ?? restJoined).trim();
 
   if (!id) {
     return null;
diff --git a/src/config/sessions/delivery-info.test.ts b/src/config/sessions/delivery-info.test.ts
index 9a435c38a7a..88c01c5a0d1 100644
--- a/src/config/sessions/delivery-info.test.ts
+++ b/src/config/sessions/delivery-info.test.ts
@@ -44,6 +44,14 @@ describe("extractDeliveryInfo", () => {
       baseSessionKey: "agent:main:slack:channel:C1",
       threadId: "123.456",
     });
+    expect(
+      parseSessionThreadInfo(
+        "agent:main:matrix:channel:!room:example.org:thread:$AbC123:example.org",
+      ),
+    ).toEqual({
+      baseSessionKey: "agent:main:matrix:channel:!room:example.org",
+      threadId: "$AbC123:example.org",
+    });
     expect(parseSessionThreadInfo("agent:main:telegram:dm:user-1")).toEqual({
       baseSessionKey: "agent:main:telegram:dm:user-1",
       threadId: undefined,