diff --git a/apps/cli/package.json b/apps/cli/package.json
index f456ddc..659e833 100644
--- a/apps/cli/package.json
+++ b/apps/cli/package.json
@@ -1,6 +1,6 @@
 {
   "name": "claudemesh-cli",
-  "version": "0.5.6",
+  "version": "0.5.7",
   "description": "Claude Code MCP client for claudemesh — peer mesh messaging between Claude sessions.",
   "keywords": [
     "claude-code",
diff --git a/apps/cli/src/mcp/server.ts b/apps/cli/src/mcp/server.ts
index ca73ef3..60c3a05 100644
--- a/apps/cli/src/mcp/server.ts
+++ b/apps/cli/src/mcp/server.ts
@@ -445,11 +445,14 @@ Your message mode is "${messageMode}".
         if (!existsSync(filePath)) return text(`share_file: file not found: ${filePath}`, true);
         const client = allClients()[0];
         if (!client) return text("share_file: not connected", true);
-        const fileId = await client.uploadFile(filePath, client.meshId, client.meshSlug, {
-          name: fileName, tags, persistent: true,
-        });
-        if (!fileId) return text("share_file: upload failed", true);
-        return text(`Shared: ${fileName ?? filePath} (${fileId})`);
+        try {
+          const fileId = await client.uploadFile(filePath, client.meshId, client.meshSlug, {
+            name: fileName, tags, persistent: true,
+          });
+          return text(`Shared: ${fileName ?? filePath} (${fileId})`);
+        } catch (e) {
+          return text(`share_file: upload failed — ${e instanceof Error ? e.message : String(e)}`, true);
+        }
       }
 
       case "get_file": {
@@ -856,7 +859,21 @@ Your message mode is "${messageMode}".
     });
   }
 
+  // Event loop keepalive: Node.js stdout to a pipe is buffered. Without
+  // periodic event loop activity, stdout.write() from WS callbacks may not
+  // flush until the next I/O event. This 1s interval keeps the event loop
+  // ticking so channel notifications flush promptly — same pattern that made
+  // claude-intercom's push delivery reliable (its 1s HTTP poll had this
+  // effect as a side effect). The interval does nothing except prevent the
+  // event loop from settling.
+  const keepalive = setInterval(() => {
+    // Intentionally empty — the interval itself keeps the event loop active.
+    // Do NOT call .unref() — that would defeat the purpose.
+  }, 1_000);
+  void keepalive; // suppress unused warning
+
   const shutdown = (): void => {
+    clearInterval(keepalive);
     stopAll();
     process.exit(0);
   };
diff --git a/apps/cli/src/ws/client.ts b/apps/cli/src/ws/client.ts
index 3dd452f..bd60d3e 100644
--- a/apps/cli/src/ws/client.ts
+++ b/apps/cli/src/ws/client.ts
@@ -526,8 +526,11 @@ export class BrokerClient {
       body: data,
       signal: AbortSignal.timeout(30_000),
     });
-    const body = await res.json() as { ok?: boolean; fileId?: string };
-    return body.fileId ?? null;
+    const body = await res.json() as { ok?: boolean; fileId?: string; error?: string };
+    if (!res.ok || !body.fileId) {
+      throw new Error(body.error ?? `HTTP ${res.status}`);
+    }
+    return body.fileId;
   }
 
   // --- Vectors ---