diff --git a/extensions/msteams/src/monitor.conversation-allowlist.lifecycle.test.ts b/extensions/msteams/src/monitor.conversation-allowlist.lifecycle.test.ts
index bab588072f3f..2b6d5ee8891f 100644
--- a/extensions/msteams/src/monitor.conversation-allowlist.lifecycle.test.ts
+++ b/extensions/msteams/src/monitor.conversation-allowlist.lifecycle.test.ts
@@ -58,6 +58,17 @@ vi.mock("../runtime-api.js", async () => {
     keepHttpServerTaskAlive: keepHttpServerTaskAliveMock,
     mergeAllowlist: (params: { existing?: string[]; additions: string[] }) =>
       Array.from(new Set([...(params.existing ?? []), ...params.additions])),
+    resolveChannelMediaMaxBytes: (params: {
+      cfg: OpenClawConfig;
+      resolveChannelLimitMb: (context: { cfg: OpenClawConfig }) => number | undefined;
+    }) => {
+      const mediaMaxMb =
+        params.resolveChannelLimitMb({ cfg: params.cfg }) ??
+        params.cfg.agents?.defaults?.mediaMaxMb;
+      return typeof mediaMaxMb === "number" && mediaMaxMb > 0
+        ? Math.floor(mediaMaxMb * 1024 * 1024)
+        : undefined;
+    },
     summarizeMapping: vi.fn(),
   };
 });
diff --git a/extensions/msteams/src/monitor.lifecycle.test.ts b/extensions/msteams/src/monitor.lifecycle.test.ts
index a79450292a46..3504b226a4fd 100644
--- a/extensions/msteams/src/monitor.lifecycle.test.ts
+++ b/extensions/msteams/src/monitor.lifecycle.test.ts
@@ -243,6 +243,14 @@ function requireRegisteredMSTeamsConfig(): OpenClawConfig {
   return registered.cfg;
 }
 
+function requireRegisteredMSTeamsMediaMaxBytes(): number {
+  const registered = registerMSTeamsHandlers.mock.calls[0]?.[1];
+  if (!registered) {
+    throw new Error("expected registered MSTeams handler dependencies");
+  }
+  return registered.mediaMaxBytes;
+}
+
 describe("monitorMSTeamsProvider lifecycle", () => {
   afterEach(() => {
     vi.clearAllMocks();
@@ -292,6 +300,49 @@ describe("monitorMSTeamsProvider lifecycle", () => {
     }
   });
 
+  it("prefers the Teams media limit over the agent default", async () => {
+    const abort = new AbortController();
+    const cfg = createConfig(0);
+    updateMSTeamsConfig(cfg, { mediaMaxMb: 12 });
+    cfg.agents = { defaults: { mediaMaxMb: 3 } };
+
+    const task = monitorMSTeamsProvider({
+      cfg,
+      runtime: createRuntime(),
+      abortSignal: abort.signal,
+      ...createStores(),
+    });
+
+    await waitForMSTeamsTestState(() => {
+      expect(registerMSTeamsHandlers).toHaveBeenCalledTimes(1);
+    });
+    expect(requireRegisteredMSTeamsMediaMaxBytes()).toBe(12 * 1024 * 1024);
+
+    abort.abort();
+    await task;
+  });
+
+  it("falls back to the agent media limit when Teams has no override", async () => {
+    const abort = new AbortController();
+    const cfg = createConfig(0);
+    cfg.agents = { defaults: { mediaMaxMb: 3 } };
+
+    const task = monitorMSTeamsProvider({
+      cfg,
+      runtime: createRuntime(),
+      abortSignal: abort.signal,
+      ...createStores(),
+    });
+
+    await waitForMSTeamsTestState(() => {
+      expect(registerMSTeamsHandlers).toHaveBeenCalledTimes(1);
+    });
+    expect(requireRegisteredMSTeamsMediaMaxBytes()).toBe(3 * 1024 * 1024);
+
+    abort.abort();
+    await task;
+  });
+
   it("rejects startup when the webhook port is already in use", async () => {
     const blocker = createServer();
     await new Promise<void>((resolve, reject) => {
diff --git a/extensions/msteams/src/monitor.ts b/extensions/msteams/src/monitor.ts
index 9131b118744e..3d26bef6e3a5 100644
--- a/extensions/msteams/src/monitor.ts
+++ b/extensions/msteams/src/monitor.ts
@@ -6,6 +6,7 @@ import {
   isDangerousNameMatchingEnabled,
   keepHttpServerTaskAlive,
   mergeAllowlist,
+  resolveChannelMediaMaxBytes,
   summarizeMapping,
   type OpenClawConfig,
   type RuntimeEnv,
@@ -205,12 +206,11 @@ export async function monitorMSTeamsProvider(
 
   const port = msteamsCfg.webhook?.port ?? 3978;
   const textLimit = core.channel.text.resolveTextChunkLimit(cfg, "msteams");
-  const MB = 1024 * 1024;
-  const agentDefaults = cfg.agents?.defaults;
   const mediaMaxBytes =
-    typeof agentDefaults?.mediaMaxMb === "number" && agentDefaults.mediaMaxMb > 0
-      ? Math.floor(agentDefaults.mediaMaxMb * MB)
-      : 8 * MB;
+    resolveChannelMediaMaxBytes({
+      cfg,
+      resolveChannelLimitMb: ({ cfg: channelCfg }) => channelCfg.channels?.msteams?.mediaMaxMb,
+    }) ?? 8 * 1024 * 1024;
   const conversationStore = opts.conversationStore ?? createMSTeamsConversationStoreState();
   const pollStore = opts.pollStore ?? createMSTeamsPollStoreState();