Description

macOS App Canvas window shows "Waiting for A2UI message" and never updates, even though A2UI push commands report success.

Environment

• macOS App version: 2026.2.1 (8650)
• Gateway version: 2026.2.1
• macOS: 26.2.0 (arm64)
• Device: Mac mini (Mac16,10)

Steps to Reproduce

1. Start Gateway with canvasHost.enabled: true
2. Open macOS App, connect as node
3. Open Canvas window (shows "Waiting for A2UI message")
4. Push A2UI content:

   openclaw nodes canvas a2ui push --jsonl /tmp/a2ui-test.jsonl --node "Mac mini"

5. CLI reports success: canvas a2ui push ok (v0.8, 2 messages)

Expected Behavior

Canvas should display the pushed A2UI content.

Actual Behavior

Canvas remains stuck on "Waiting for A2UI message".

Verification

• A2UI host is running: curl http://127.0.0.1:18789/__openclaw__/a2ui/ returns 200
• Node is connected: openclaw nodes status shows connected: true
• Push succeeds: CLI confirms canvas a2ui push ok

A2UI Test Payload

{"surfaceUpdate":{"surfaceId":"main","components":[{"id":"root","component":{"Column":{"children":{"explicitList":["title","content"]}}}},{"id":"title","component":{"Text":{"text":{"literalString":"Hello"},"usageHint":"h1"}}},{"id":"content","component":{"Text":{"text":{"literalString":"Test"},"usageHint":"body"}}}]}}
{"beginRendering":{"surfaceId":"main","root":"root"}}

Notes

• canvas.present with a URL works (shows the webpage)
• canvas.navigate works
• Only A2UI push doesn't display