Bug Description

The OpenClaw message tool fails when sending messages through Discord with a schema validation error:

Validation failed for tool "message": - buttons: must have required property 'buttons'

This makes the native Discord integration completely unusable — any inbound Discord message that triggers a reply results in the error "Something went wrong while processing your request. Please try again, or use /new to start a fresh session."

Environment

• OpenClaw version: 2026.4.12 (1c0672b)
• OS: Ubuntu Linux (kernel 6.8.0-107-generic, x64)
• Node: v22.22.0
• Discord channel: enabled via bot token
• Model: Any (reproduces regardless of model)

Reproduction Steps

1. Configure Discord channel with bot token in openclaw.json
2. Enable Discord guild and channel(s)
3. Send any message in a configured Discord channel
4. OpenClaw receives the message and attempts to reply via the message tool
5. Reply fails with the schema validation error

Workaround

Using the Discord REST API directly via curl works fine:

curl -s -X POST \
  -H "Authorization: Bot <TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{"content":"message"}' \
  "https://discord.com/api/v10/channels/<CHANNEL_ID>/messages"

Related Issues

• Discord: asVoice conflicts with required components schema — cannot send voice messages with pre-recorded audio #51447 — Discord asVoice conflicts with required components schema
• [Bug]: Discord components v2 — models lack guidance on media sends, media silently dropped #53269 — Discord components v2 schema issues
• Discord interactive components: reusable:false expires per-button not per-panel, and editMessage broken due to message/content field mismatch #54233 — Discord interactive components broken

Expected Behavior

The message tool should send a plain text reply to Discord without requiring a buttons property when no interactive components are included.