[Bug] Browser-use subagent announce delivery fails on Feishu channel - shows "Agent couldn't generate a response"

[arjankahofmanz-dotcom]

Bug Description

When a browser-use subagent completes a task and tries to auto-announce the result back to the Feishu (飞书/Lark) channel, the user sees the error message:

⚠️ Agent couldn't generate a response. Please try again.

The subagent itself completes successfully and generates a valid response, but the announce delivery step to Feishu fails.

Steps to Reproduce

1. Configure EasyClaw with Feishu as a messaging channel
2. Ask the assistant to perform a browser task (e.g., "打开浏览器，帮我打开DeepSeek的官网")
3. The browser-use subagent spawns and completes the task successfully
4. The subagent's auto-announce delivery to Feishu fails
5. User sees "⚠️ Agent couldn't generate a response" in Feishu DM

Expected Behavior

The subagent's response should be delivered to the Feishu channel normally.

Actual Behavior

The announce delivery fails with "Agent couldn't generate a response" error on the Feishu channel.

Workaround

The main agent can manually relay the subagent's result to the user instead of relying on auto-announce delivery. This works consistently.

Environment

• OS: Windows_NT 10.0.20348 (x64)
• EasyClaw version: 2026.4.14
• Channel: Feishu (飞书)
• Subagent: browser-use
• Model: qwen/qwen3.7-plus (main), various (subagent)

Additional Context

• The issue is specific to the Feishu channel. The same browser-use subagent works fine when delivering to other channels (e.g., webchat/easyclawapp).
• The subagent's task execution is always successful - only the announce/delivery step fails.
• This appears to be a compatibility issue between the browser-use subagent's announce format and the Feishu channel's message handling.